1.
Polymer
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A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Because of their range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure, Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. The units composing polymers derive, actually or conceptually, from molecules of low molecular mass. The term was coined in 1833 by Jöns Jacob Berzelius, though with a distinct from the modern IUPAC definition. The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger, Polymers are studied in the fields of biophysics and macromolecular science, and polymer science. Polyisoprene of latex rubber is an example of a polymer. In biological contexts, essentially all biological macromolecules—i. e, proteins, nucleic acids, and polysaccharides—are purely polymeric, or are composed in large part of polymeric components—e. g. Isoprenylated/lipid-modified glycoproteins, where small molecules and oligosaccharide modifications occur on the polyamide backbone of the protein. The simplest theoretical models for polymers are ideal chains, Polymers are of two types, Natural polymeric materials such as shellac, amber, wool, silk and natural rubber have been used for centuries. A variety of natural polymers exist, such as cellulose. Most commonly, the continuously linked backbone of a used for the preparation of plastics consists mainly of carbon atoms. A simple example is polyethylene, whose repeating unit is based on ethylene monomer, however, other structures do exist, for example, elements such as silicon form familiar materials such as silicones, examples being Silly Putty and waterproof plumbing sealant. Oxygen is also present in polymer backbones, such as those of polyethylene glycol, polysaccharides. Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain or network, during the polymerization process, some chemical groups may be lost from each monomer. This is the case, for example, in the polymerization of PET polyester, the distinct piece of each monomer that is incorporated into the polymer is known as a repeat unit or monomer residue. Laboratory synthetic methods are divided into two categories, step-growth polymerization and chain-growth polymerization. However, some methods such as plasma polymerization do not fit neatly into either category
2.
Organic chemistry
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Study of structure includes many physical and chemical methods to determine the chemical composition and the chemical constitution of organic compounds and materials. In the modern era, the range extends further into the table, with main group elements, including, Group 1 and 2 organometallic compounds. They either form the basis of, or are important constituents of, many products including pharmaceuticals, petrochemicals and products made from them, plastics, fuels and explosives. Before the nineteenth century, chemists generally believed that compounds obtained from living organisms were endowed with a force that distinguished them from inorganic compounds. According to the concept of vitalism, organic matter was endowed with a vital force, during the first half of the nineteenth century, some of the first systematic studies of organic compounds were reported. Around 1816 Michel Chevreul started a study of soaps made from various fats and he separated the different acids that, in combination with the alkali, produced the soap. Since these were all compounds, he demonstrated that it was possible to make a chemical change in various fats, producing new compounds. In 1828 Friedrich Wöhler produced the chemical urea, a constituent of urine, from inorganic starting materials. The event is now accepted as indeed disproving the doctrine of vitalism. In 1856 William Henry Perkin, while trying to manufacture quinine accidentally produced the organic dye now known as Perkins mauve and his discovery, made widely known through its financial success, greatly increased interest in organic chemistry. A crucial breakthrough for organic chemistry was the concept of chemical structure, ehrlich popularized the concepts of magic bullet drugs and of systematically improving drug therapies. His laboratory made decisive contributions to developing antiserum for diphtheria and standardizing therapeutic serums, early examples of organic reactions and applications were often found because of a combination of luck and preparation for unexpected observations. The latter half of the 19th century however witnessed systematic studies of organic compounds, the development of synthetic indigo is illustrative. The production of indigo from plant sources dropped from 19,000 tons in 1897 to 1,000 tons by 1914 thanks to the methods developed by Adolf von Baeyer. In 2002,17,000 tons of indigo were produced from petrochemicals. In the early part of the 20th Century, polymers and enzymes were shown to be large organic molecules, the multiple-step synthesis of complex organic compounds is called total synthesis. Total synthesis of natural compounds increased in complexity to glucose. For example, cholesterol-related compounds have opened ways to synthesize complex human hormones, since the start of the 20th century, complexity of total syntheses has been increased to include molecules of high complexity such as lysergic acid and vitamin B12
3.
Carbamate
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A carbamate is an organic compound derived from carbamic acid. A carbamate group, carbamate ester, and carbamic acids are functional groups that are inter-related structurally, carbamate esters are also called urethanes. Carbamic acids are derived from amines, R2NH + CO2 → R2NCO2H Carbamic acid is about as acidic as acetic acid, n-terminal amino groups of valine residues in the α- and β-chains of deoxyhemoglobin exist as carbamates. They help to stabilise the protein, when it becomes deoxyhemoglobin and this stabilizing effect should not be confused with the Bohr effect. The ε-amino groups of the residues in urease and phosphotriesterase also feature carbamate. The carbamate derived from aminoimidazole is an intermediate in the biosynthesis of inosine, carbamoyl phosphate is generated from carboxyphosphate rather than CO2. Perhaps the most important carbamate is the one involved in the capture of CO2 by plants since this process is necessary for their growth, the enzyme ribulose 1, 5-bisphosphate carboxylase/oxygenase fixes a molecule of carbon dioxide as phosphoglycerate in the Calvin cycle. At the active site of the enzyme, a Mg2+ ion is bound to glutamate and aspartate residues as well as a lysine carbamate. The carbamate is formed when an uncharged lysine side chain near the ion reacts with a carbon dioxide molecule from the air, which renders it charged. The so-called carbamate insecticides feature the carbamate ester functional group, included in this group are aldicarb, carbofuran, carbaryl, ethienocarb, fenobucarb, oxamyl, and methomyl. These insecticides kill insects by reversibly inactivating the enzyme acetylcholinesterase, the organophosphate pesticides also inhibit this enzyme, although irreversibly, and cause a more severe form of cholinergic poisoning. Fenoxycarb has a group but acts as a juvenile hormone mimic. The insect repellent icaridin is a substituted carbamate, polyurethanes contain multiple carbamate groups as part of their structure. The urethane in the name refers to these carbamate groups. In contrast, the commonly called urethane, ethyl carbamate, is neither a component of polyurethanes. Urethanes are usually formed by reaction of an alcohol with an isocyanate, commonly, urethanes made by a non-isocyanate route are called carbamates. Polyurethane polymers have a range of properties and are commercially available as foams, elastomers. Typically, polyurethane polymers are made by combining diisocyanates, e. g. Urethane was once produced commercially in the United States as an antineoplastic agent and it was found to be toxic and largely ineffective
4.
Isocyanate
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Isocyanate is the functional group with the formula R–N=C=O. Organic compounds that contain a group are referred to as isocyanates. An isocyanate that has two groups is known as a di-isocyanate. Di-isocyanates are manufactured for reactions with polyols in the production of polyurethanes, isocyanates should not be confused with cyanate esters and isocyanides, whose behaviors are very different. The cyanate functional group is arranged differently from the isocyanate group, isocyanides have the connectivity R-N≡C, lacking the oxygen of the cyanate groups. Isocyanates are produced by treating amines with phosgene, RNH2 + COCl2 → RNCO +2 HCl These reactions proceed via the intermediacy of a carbamoyl chloride, owing to the hazards associated with phosgene, the production of isocyanates requires special precautions. Isocyanates are electrophiles, and as such they are reactive toward a variety of nucleophiles including alcohols, amines, isocyanates react with water to form carbon dioxide, RNCO + H2O → RNH2 + CO2 This reaction is exploited in tandem with the production of polyurethane to give polyurethane foams. The carbon dioxide functions as a blowing agent, isocyanates also can react with themselves. Aliphatic di-isocyanates can form trimers, which are related to cyanuric acid. Isocyanates participate in Diels-Alder reactions, functioning as dienophiles, schmidt reaction, a reaction where a carboxylic acid is treated with ammonia and hydrazoic acid yielding an isocyanate. Curtius rearrangement degradation of an azide to an isocyanate and nitrogen gas. Lossen rearrangement, the conversion of an acid to an isocyanate via the formation of an O-acyl, sulfonyl. A monofunctional isocyanate of industrial significance is methyl isocyanate, which is used in the manufacture of pesticides, lD50s are typically several hundred milligrams per kilogram. Isocyanates are potentially dangerous irritants to the eyes and respiratory tract, methyl isocyanate was the chemical released in the Bhopal disaster causing the death of nearly 4000 people. Polyurethanes have variable curing times, and the presence of free isocyanates in foams vary accordingly, prepared by the Institute of Occupational Medicine for the Health and Safety Executive
5.
Polyol
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A polyol is an alcohol containing multiple hydroxyl groups. In two different technological disciplines the term polyol has a meaning, food science and polymer chemistry. They are also added to chewing gum because they are not broken down by bacteria in the mouth or metabolized to acids, maltitol, sorbitol, xylitol, erythritol, and isomalt are some of the more common types. Sugar alcohols may be formed under reducing conditions from their analogue sugars. In polymer chemistry, polyols are compounds with multiple functional groups available for organic reactions. A molecule with two groups is a diol, one with three is a triol, one with four is a tetrol and so on. Monomeric polyols such as glycerin, pentaerythritol, ethylene glycol and sucrose often serve as the point for polymeric polyols. These materials are referred to as the initiators and reacted with propylene oxide or ethylene oxide to produce polymeric polyols. However, they should not be confused with radical initiators used to promote other polymerization reactions. The functional group used as the point for a polymeric polyol need not be a hydroxyl group. A primary amino group often functions as the point for two polymeric chains, especially in the case of polyether polyols. Polymeric polyols are used to produce other polymers. They are reacted with isocyanates to make polyurethanes used to make mattresses, foam insulation for appliances, home and automotive seats, elastomeric shoe soles, fibers, polymeric polyols are usually polyethers or polyesters. Common polyether diols are polyethylene glycol, polypropylene glycol, and poly glycol, the examples shown below are fairly low molecular weight triols based on glycerin being reacted with propylene oxide, ethylene oxide or a combination of the two. In reality, the chains would not be of length in any one molecule. Polyether polyols account for about 90% of the polymeric polyols used industrially, another class of polymeric polyols is the polyesters. Polyesters are formed by condensation or step-growth polymerization of diols and dicarboxylic acids, alternatively, the hydroxyl group and the carboxylic acid may be within the same molecule, as in the case of caprolactone. The example below is a structure that could be obtained by reacting pentaerythritol with gamma-butyrolactone
6.
Functional group
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In organic chemistry, functional groups are specific groups of atoms or bonds within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of, however, its relative reactivity can be modified by other functional groups nearby. The atoms of functional groups are linked to other and to the rest of the molecule by covalent bonds. Any subgroup of atoms of a compound also may be called a radical, and if a covalent bond is broken homolytically, Functional groups can also be charged, e. g. in carboxylate salts, which turns the molecule into a polyatomic ion or a complex ion. Complexation and solvation is also caused by interactions of functional groups. In the common rule of thumb like dissolves like, it is the shared or mutually well-interacting functional groups give rise to solubility. For example, sugar dissolves in water because both share the functional group and hydroxyls interact strongly with each other. Combining the names of groups with the names of the parent alkanes generates what is termed a systematic nomenclature for naming organic compounds. In traditional nomenclature, the first carbon atom after the carbon that attaches to the group is called the alpha carbon, the second, beta carbon. IUPAC conventions call for numeric labeling of the position, e. g. 4-aminobutanoic acid, in traditional names various qualifiers are used to label isomers, for example isopropanol is an isomer is n-propanol. The following is a list of functional groups. In the formulas, the symbols R and R usually denote an attached hydrogen, or a side chain of any length. Functional groups, called hydrocarbyl, that only carbon and hydrogen. Each one differs in type of reactivity, there are also a large number of branched or ring alkanes that have specific names, e. g. tert-butyl, bornyl, cyclohexyl, etc. Hydrocarbons may form charged structures, positively charged carbocations or negative carbanions, examples are tropylium and triphenylmethyl cations and the cyclopentadienyl anion. Haloalkanes are a class of molecule that is defined by a carbon–halogen bond and this bond can be relatively weak or quite stable. In general, with the exception of fluorinated compounds, haloalkanes readily undergo nucleophilic substitution reactions or elimination reactions, the substitution on the carbon, the acidity of an adjacent proton, the solvent conditions, etc. all can influence the outcome of the reactivity. Compounds that contain nitrogen in this category may contain C-O bonds, compounds that contain sulfur exhibit unique chemistry due to their ability to form more bonds than oxygen, their lighter analogue on the periodic table
7.
Gasket
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A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. Gaskets allow for mating surfaces on machine parts where they can fill irregularities. Gaskets are commonly produced by cutting from sheet materials, gaskets for specific applications, such as high pressure steam systems, may contain asbestos. However, due to hazards associated with asbestos exposure, non-asbestos gasket materials are used when practical. A few gaskets require an application of sealant directly to the surface to function properly. Some gaskets are made entirely of metal and rely on a surface to accomplish the seal. This is typical of some ring joints or some other metal gasket systems and these joints are known as R-con and E-con compressive type joints. Gaskets are normally made from a material, a sheet such as paper, rubber, silicone, metal, cork, felt, neoprene, nitrile rubber, fiberglass. One of the desirable properties of an effective gasket in industrial applications for compressed fiber gasket material is the ability to withstand high compressive loads. Most industrial gasket applications involve bolts exerting compression well into the 14 MPa range or higher, generally speaking, there are several truisms that allow for better gasket performance. One of the tried and tested is, The more compressive load exerted on the gasket. There are several ways to measure a gasket materials ability to withstand compressive loading, the hot compression test is probably the most accepted of these tests. Most manufacturers of materials will provide or publish the results of these tests. This can lead to a crude, fast and cheap gasket, in previous times the material was compressed asbestos, but in modern times a fibrous material such as graphite is used. These gaskets can fill various different chemical requirements based on the inertness of the material used, non-asbestos gasket sheet is durable, of multiple materials, and thick in nature. Material examples are mineral, carbon or nitrile synthetic rubber, applications using sheet gaskets involve acids, corrosive chemicals, steam or mild caustics. Flexibility and good recovery prevent breakage during installation of a sheet gasket, the idea behind solid material is to use metals which cannot be punched out of sheets but are still cheap to produce. These gaskets generally have a higher level of quality control than sheet gaskets
8.
Steel roller coaster
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A steel roller coaster is a roller coaster that is defined by having a track made of steel. Steel coasters have earned immense popularity in the past 50 years throughout the world, arrow Dynamics first introduced the steel roller coaster to feature tubular track to the thrill industry with their creations of the Matterhorn Bobsleds in 1959 and the Runaway Mine Train in 1966. As of 2006, the oldest operating roller coaster in North America is Little Dipper at Memphis Kiddie Park in Brooklyn. The oldest operating steel rollercoaster in the world is Montaña Suiza at Parque de Atracciones Monte Igueldo and it has been operating since 1928. Steel coasters have a smoother ride than their wooden counterparts and due to their strength rides can have more complex and faster turns. Although some coaster enthusiasts prefer wooden coasters because the ride tosses you around more making the ride feel more dangerous, almost all world records for tallest, fastest, and longest coasters are currently held by steel roller coasters. The fact that fewer supports are needed means steel roller coasters have made a variety of features possible, such as loops, barrel rolls, corkscrews, zero-G rolls. There are different types of coasters, such as flying, inverted, floorless. Kingda Ka at Six Flags Great Adventure – worlds tallest and second fastest roller coaster Leviathan at Canadas Wonderland – the tallest and fastest coaster in Canada. Matterhorn Bobsleds at Disneyland – first tubular steel roller coaster Millennium Force at Cedar Point – first full circuit roller coaster to top 300 ft, the Smiler at Alton Towers - worlds first Infinity coaster and with 14 inversions has the world record for most track inversions. Opened in 2011 Taron at Phantasialand - fastest Launched roller coaster in Europe, wicked Twister at Cedar Point - worlds tallest and fastest inverted roller coaster
9.
Escalator
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An escalator is a vertical transportation device in the form of a moving staircase – a conveyor which carries people between floors of a building. It consists of a chain of individually linked steps. These steps are guided on either side by a pair of tracks which force them to remain horizontal, escalators are used around the world in places where elevators would be impractical. Principal areas of usage include department stores, shopping malls, airports, transit systems, convention centers, hotels, arenas, stadiums, escalators have the capacity to move a large number of people, and they can be placed in the same physical space as a staircase. They have no waiting interval, they can be used to guide people toward main exits or special exhibits, a non-functioning escalator can function as a normal staircase, whereas many other conveyances become useless when they break down. Escalators, like moving walkways, move at constant speeds of around 0. 3–0.6 metres per second, the typical angle of inclination of an escalator to the horizontal is 30 degrees, and the total difference in height can be about 18 metres or more. Modern escalators have single-piece aluminum or stainless steel steps that move on a system of tracks in a continuous loop, escalators have three typical configuration options, parallel, crisscross, and multiple parallel. As a safety measure, escalators are required to have moving handrails that keep pace with the movement of the steps and this helps riders steady themselves, especially when stepping onto the moving stairs. Occasionally, a handrail will move at a different speed from the steps. The loss of synchronization between handrail and step speed can result from slippage and wear, as a result, escalators must have moving handrails that move at the same speed as the moving stairs of the escalator. The direction of movement can be permanently set, or controlled manually depending on the predominant flow of the crowd. In some setups, the direction is controlled by whoever arrives first, a number of factors affect escalator design. These include physical requirements, location, traffic patterns, safety considerations, foremost, physical factors like the vertical and horizontal distance to be spanned must be considered. These factors will determine the length and pitch of the escalator, the building infrastructure must be able to support the heavy components. The escalator should be located where it can be seen by the general public. Furthermore, up and down escalator traffic should be physically separated, traffic patterns must also be anticipated. The escalators must be designed to carry the number of passengers. For example, a single-width escalator traveling at about 0.5 metres per second can move about 2000 people per hour, the carrying capacity of an escalator system must match the expected peak traffic demand
10.
Shopping cart
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Customers can then also use the cart to transport their purchased goods to their cars. In many places in the United States, customers are allowed to leave the carts in designated areas within the parking lot, in many continental European premises, however, coin- operated locking mechanisms are provided to encourage shoppers to return the carts to the correct location after use. The carts can come in sizes, with larger ones able to carry a child. There are also specialized carts designed for two children, and electric mobility scooters with baskets designed for disabled customers, in the United States,24,000 children are injured each year in shopping carts. Some stores both in the USA and internationally have child carrying carts that look like a car or van with a seat where a child can sit equipped with a steering wheel and sometimes a horn. Such Car-Carts may offer protection and convenience by keeping the child restrained, lower to the ground, protected from falling items, shopping carts are usually fitted with four wheels, however if any one wheel jams the cart can become difficult to handle. Most carts in the United States have swivel wheels at the front, while the wheels are fixed in orientation. This difference in design correlates with smaller retail premises in Europe, an alternative to the shopping cart is a small hand-held shopping basket. A customer may prefer a basket for a amount of merchandise. One of the first shopping carts was introduced on June 4,1937, one night, in 1936, Goldman sat in his office wondering how customers might move more groceries. He found a wooden folding chair and put a basket on the seat, Goldman and one of his employees, a mechanic named Fred Young, began tinkering. Their first shopping cart was a frame that held two wire baskets. Since they were inspired by the chair, Goldman called his carts folding basket carriers. Another mechanic, Arthur Kosted, developed a method to mass-produce the carts by inventing an assembly line capable of forming and welding the wire, the cart was awarded patent number 2,196,914 on April 9,1940, titled, Folding Basket Carriage for Self-Service Stores. They advertised the invention as part of a new “No Basket Carrying Plan, Goldman had already pioneered self-serve stores and carts were part of the self-serve retail concept. The invention did not catch on immediately, men found them effeminate, women found them suggestive of a baby carriage. Ive pushed my last baby, an offended woman informed Goldman, instead of baskets, these carts are built to hold the paper bags dispensed by the grocery store. Another shopping cart innovator was Orla Watson, who invented the rear door to allow for nesting in 1946
11.
Elevator
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An elevator or lift is a type of vertical transportation that moves people or goods between floors of a building, vessel, or other structure. Elevators are generally powered by electric motors that either drive traction cables or counterweight systems like a hoist, in agriculture and manufacturing, an elevator is any type of conveyor device used to lift materials in a continuous stream into bins or silos. Several types exist, such as the chain and bucket elevator, grain auger screw conveyor using the principle of Archimedes screw, or the chain, languages other than English may have loanwords based on either elevator or lift. Because of wheelchair access laws, elevators are often a requirement in new multistory buildings. The earliest known reference to an elevator is in the works of the Roman architect Vitruvius, some sources from later historical periods mention elevators as cabs on a hemp rope powered by hand or by animals. In 1000, the Book of Secrets by al-Muradi in Islamic Spain described the use of a lifting device. In the 17th century the prototypes of elevators were located in the buildings of England. Louis XV of France had a flying chair built for one of his mistresses at the Chateau de Versailles in 1743. Ancient and medieval elevators used drive systems based on hoists or winders, the invention of a system based on the screw drive was perhaps the most important step in elevator technology since ancient times, leading to the creation of modern passenger elevators. The first screw drive elevator was built by Ivan Kulibin and installed in Winter Palace in 1793, several years later another of Kulibins elevators was installed in Arkhangelskoye near Moscow. The development of elevators was led by the need for movement of raw materials including coal, the technology developed by these industries and the introduction of steel beam construction worked together to provide the passenger and freight elevators in use today. Starting in the mines, by the mid-19th century elevators were operated with steam power and were used for moving goods in bulk in mines and factories. It elevated paying customers to a height in the center of London. Early, crude steam-driven elevators were refined in the decade, – in 1835 an innovative elevator called the Teagle was developed by the company Frost. The elevator was belt-driven and used a counterweight for extra power, the hydraulic crane was invented by Sir William Armstrong in 1846, primarily for use at the Tyneside docks for loading cargo. These quickly supplanted the steam driven elevators, exploiting Pascals law. A water pump supplied a variable level of pressure to a plunger encased inside a vertical cylinder. Counterweights and balances were used to increase the lifting power of the apparatus
12.
Skateboard
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A skateboard is a type of sports equipment or toy used primarily for the activity of skateboarding. It usually consists of a specially designed maplewood board combined with a coating used for making smoother slides. Most skateboards are made with 7 plies of this wood, a skateboard is moved by pushing with one foot while the other remains on the board, or by pumping ones legs in structures such as a bowl or half pipe. A skateboard can also be used by standing on the deck while on a downward slope and allowing gravity to propel the board. If the riders leading foot is their right foot, he/she is said to ride goofy, if the leading foot is their left foot. If the rider is regular but chooses to ride goofy, he/she is said to be riding in switch. Recently, electric skateboards have also appeared and these no longer require the propelling of the skateboard by means of the feet, rather an electric motor propels the board, fed by an electric battery. There is no governing body that declares any regulations on what constitutes a skateboard or the parts from which it is assembled. Historically, the skateboard has conformed both to contemporary trends and to the array of stunts performed by riders/users, who require a certain functionality from the board. Of course, the shape depends largely upon its desired function. Longboards are a type of skateboard with a wheelbase and larger, softer wheels. The two main types of skateboards are the longboard and the shortboard, the shape of the board is also important, the skateboard must be concaved to perform tricks. Longboards are usually faster and are used for cruising and racing. See, Skateboarding The following descriptions cover skateboard parts that are most prevalent in popular, many parts exist with exotic or alternative constructions. A traditional complete skateboard consists of the deck, trucks, wheels, bushings, nuts and bolts to fasten the truck, older decks also included plastic parts such as side, tail, and nose guards. Modern decks vary in size, but most are 7 to 10.5 inches wide, wider decks can be used for greater stability when skateboarding. Standard skateboard decks are usually between 28 and 33 inches long, the underside of the deck can be printed with a design by the manufacturer, blank, or decorated by any other means. Long boards are usually over 36 inches long, plastic penny boards are typically about 22 inches long
13.
Adhesive
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The use of adhesives offers many advantages over binding techniques such as sewing, mechanical fastening, thermal bonding, etc. Adhesives are typically organized by the method of adhesion and these are then organized into reactive and non-reactive adhesives, which refers to whether the adhesive chemically reacts in order to harden. Alternatively they can be organized by whether the raw stock is of natural or synthetic origin, Adhesives may be found naturally or produced synthetically. The earliest human use of substances was approximately 200,000 years ago. The first references to adhesives in literature first appeared in approximately 2000 BCE, the Greeks and Romans made great contributions to the development of adhesives. In Europe, glue was not widely used until the period 1500–1700 CE, from then until the 1900s increases in adhesive use and discovery were relatively gradual. Only since the last century has the development of synthetic adhesives accelerated rapidly, the earliest use of adhesives was discovered in central Italy when two stone flakes partially covered with birch-bark tar and a third uncovered stone from the Middle Pleistocene era were found. This is thought to be the oldest discovered human use of tar-hafted stones, the birch-bark-tar adhesive is a simple, one-component adhesive. Although sticky enough, plant-based adhesives are brittle and vulnerable to environmental conditions, the first use of compound adhesives was discovered in Sibudu, South Africa. The ability to produce stronger adhesives allowed middle stone age humans to attach stone segments to sticks in greater variations, more recent examples of adhesive use by prehistoric humans have been found at the burial sites of ancient tribes. Archaeologists studying the sites found that approximately 6,000 years ago the tribesmen had buried their dead together with food found in clay pots repaired with tree resins. The glue was analyzed as pitch, which requires the heating of tar during its production, the retrieval of this tar requires a transformation of birch bark by means of heat, in a process known as pyrolysis. The first references to adhesives in literature first appeared in approximately 2000 BCE, further historical records of adhesive use are found from the period spanning 1500–1000 BCE. Artifacts from this period include paintings depicting wood gluing operations and a made of wood. Other ancient Egyptian artifacts employ animal glue for bonding or lamination, such lamination of wood for bows and furniture is thought to have extended their life and was accomplished using casein -based glues. The ancient Egyptians also developed starch-based pastes for the bonding of papyrus to clothing, from 1 to 500 AD the Greeks and Romans made great contributions to the development of adhesives. Wood veneering and marquetry were developed, the production of animal and fish glues refined, egg-based pastes were used to bond gold leaves incorporated various natural ingredients such as blood, bone, hide, milk, cheese, vegetables, and grains. The Greeks began the use of slaked lime as mortar while the Romans furthered mortar development by mixing lime with volcanic ash and this material, known as pozzolanic cement, was used in the construction of the Roman Colosseum and Pantheon
14.
Synthetic fiber
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Synthetic fibers is the result of extensive research by scientists to improve on naturally occurring animal and plant fibres. In general, synthetic fibers are created by extruding fiber forming materials through spinnerets into air and water, before synthetic fibres were developed, artificially manufactured fibres were made from polymers obtained from petrochemicals. These fibres are called synthetic or artificial fibres, some fibres are manufactured from plant-derived cellulose. Joseph Swan invented the first synthetic fiber in the early 1880s and his fiber was drawn from a cellulose liquid, formed by chemically modifying the fiber contained in tree bark. In 1885, he unveiled fabrics he had manufactured from his material at the International Inventions Exhibition in London. The next step was taken by Hilaire de Chardonnet, a French engineer and industrialist, who invented the first artificial silk, in the late 1870s, Chardonnet was working with Louis Pasteur on a remedy to the epidemic that was destroying French silkworms. Failure to clean up a spill in the darkroom resulted in Chardonnets discovery of nitrocellulose as a replacement for real silk. Realizing the value of such a discovery, Chardonnet began to develop his new product, unfortunately, Chardonnets material was extremely flammable, and was subsequently replaced with other, more stable materials. The first successful process was developed in 1894 by English chemist Charles Frederick Cross and they named the fiber viscose, because the reaction product of carbon disulfide and cellulose in basic conditions gave a highly viscous solution of xanthate. The first commercial viscose rayon was produced by the UK company Courtaulds Fibers in 1905, the name rayon was adopted in 1924, with viscose being used for the viscous organic liquid used to make both rayon and cellophane. A similar product known as cellulose acetate was discovered in 1865, rayon and acetate are both artificial fibers, but not truly synthetic, being made from wood. Nylon, the first synthetic fiber, was developed by Wallace Carothers and it soon made its debut in the United States as a replacement for silk, just in time for the introduction of rationing during World War II. Its novel use as a material for womens stockings overshadowed more practical uses, such as a replacement for the silk in parachutes, the first polyester fiber was introduced by John Rex Whinfield and James Tennant Dickson, British chemists working at the Calico Printers Association, in 1941. They produced and patented the first polyester fibre which they named Terylene, also known as Dacron, equal to or surpassing nylon in toughness, ICI and DuPont went on to produce their own versions of the fibre. The world production of fibers was 55.2 million tonnes in 2014. Synthetic fibers are made from synthesized polymers or small molecules, the compounds that are used to make these fibers come from raw materials such as petroleum based chemicals or petrochemicals. These materials are polymerized into a long, linear chemical that bond two adjacent carbon atoms, differing chemical compounds will be used to produce different types of fibers. Synthetic fibers account for half of all fiber usage, with applications in every field of fiber
15.
Spandex
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Spandex, Lycra or elastane is a synthetic fiber known for its exceptional elasticity. It is stronger and more durable than natural rubber and it is a polyester-polyurethane copolymer that was invented in 1958 by chemist Joseph Shivers at DuPonts Benger Laboratory in Waynesboro, Virginia. When introduced in 1962, it revolutionized many areas of the clothing industry, the name spandex is an anagram of the word expands. Brand names for spandex include Lycra, Elaspan, Acepora, Creora, INVIYA, ROICA and Dorlastan, Linel, Spandex fibers are produced in four different ways, melt extrusion, reaction spinning, solution dry spinning, and solution wet spinning. All of these include the initial step of reacting monomers to produce a prepolymer. Once the prepolymer is formed, it is reacted further in various ways, the solution dry spinning method is used to produce over 94. 5% of the worlds spandex fibers, and the process has five steps,1. The first step is to produce the prepolymer and this is done by mixing a macroglycol with a diisocyanate monomer. The two compounds are mixed in a vessel to produce a prepolymer. A typical ratio of glycol to diisocyanate is 1,2, the prepolymer is further reacted with an equal amount of diamine. This reaction is known as chain extension reaction, the resulting solution is diluted with a solvent to produce the spinning solution. The solvent helps make the solution thinner and more easily handled, the spinning solution is pumped into a cylindrical spinning cell where it is cured and converted into fibers. In this cell, the solution is forced through a metal plate called a spinneret. This causes the solution to be aligned in strands of liquid polymer, as the strands pass through the cell, they are heated in the presence of a nitrogen and solvent gas. This process causes the polymer to react chemically and form solid strands. As the fibers exit the cell, an amount of solid strands are bundled together to produce the desired thickness, each fiber of spandex is made up of many smaller individual fibers that adhere to one another due to the natural stickiness of their surface. The resulting fibers are treated with a finishing agent which can be magnesium stearate or another polymer. This treatment prevents the fibers sticking together and aids in textile manufacture, the fibers are then transferred through a series of rollers onto a spool. Because of its elasticity and strength, spandex has been incorporated into a range of garments
16.
Carpet
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A carpet is a textile floor covering typically consisting of an upper layer of pile attached to a backing. The pile was made from wool, but, since the 20th century, synthetic fibers such as polypropylene, nylon or polyester are often used. The pile usually consists of twisted tufts which are typically heat-treated to maintain their structure, Carpets can be made in any colour by using differently dyed fibers. Carpets can have different types of patterns and motifs used to decorate the surface. In the 2000s, carpets are used in industrial and commercial establishments such as stores and hotels. Carpet is commonly made in widths of 12 feet and 15 feet in the USA,4 m and 5 m in Europe. Wall-to-wall carpet is distinguished from rugs or mats, which are loose-laid floor coverings, as wall-to-wall carpet is fixed to the floor, child labour has often been used in Asia for hand knotting rugs. The term carpet comes from Old French carpite, one derivation of the term states that the French term came from the Old Italian carpita, from the verb carpire meaning to pluck. The Online Etymology Dictionary states that the carpet was first used in English in the late 13th century, with the meaning coarse cloth. The Online Etymology Dictionary states that the term comes, the meaning of the term carpet shifted in the 15th century to refer to floor coverings. The term carpet is used interchangeably with the term rug. Some sources define a carpet as stretching from wall to wall, another definition treats rugs as of lower quality or of smaller size, with carpets quite often having finished ends. A third common definition is that a carpet is fixed in place while a rug is simply laid out on the floor. Historically, the carpet was also applied to table and wall coverings. The term rug was first used in English in the 1550s, the term is of. Scandinavian origin, compare Norwegian dialectal rugga coarse coverlet, from Old Norse rogg shaggy tuft, from Proto-Germanic *rawwa-, perhaps related to rag and rough. The meaning of rug. evolved to coverlet, wrap, then mat for the floor, the carpet is produced on a loom quite similar to woven fabric. The pile can be plush or Berber, plush carpet is a cut pile and Berber carpet is a loop pile. There are new styles of carpet combining the two styles called cut and loop carpeting, normally many colored yarns are used and this process is capable of producing intricate patterns from predetermined designs
17.
IG Farben
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IG Farben was a German chemical and pharmaceutical industry conglomerate. Its name is taken from Interessen-Gemeinschaft Farbenindustrie AktienGesellschaft, the company was formed in 1925 from a number of major chemical companies that had been working together closely since World War I. During its heyday, IG Farben was both the largest company in Europe overall and the largest chemical and pharmaceutical company in the world, IG Farben scientists made fundamental contributions to all areas of chemistry and the pharmaceutical industry. Notably IG Farben scientists discovered the first antibiotic, fundamentally reformed medical research, otto Bayer discovered the polyaddition for the synthesis of polyurethane in 1937. Several IG Farben scientists were awarded Nobel Prizes, Carl Bosch and Friedrich Bergius were awarded the Nobel Prize in Chemistry in 1931 in recognition of their contributions to the invention and development of chemical high pressure methods. Gerhard Domagk was awarded the Nobel Prize in Physiology or Medicine in 1939 for the discovery of the effects of prontosil. Kurt Alder was awarded the Nobel Prize in Chemistry in 1950 for his discovery, following the Nazi takeover of Germany, the company became embroiled in the Nazi regimes policies as a large government contractor. In 1951, IG Farben was split into its four largest original constituent companies, the current main successor companies are AGFA, BASF, Bayer and Sanofi. IG Farben was founded on 9 December 1925, as a merger of the six companies. Weiler Ter Meer At the beginning of the 20th century, the German chemical industry dominated the market for synthetic dyes. Weiler-ter Meer concentrated on high-quality specialty dyes, in 1913, these eight firms produced almost 90% of the world supply of dyestuffs and sold about 80% of their production abroad. Because of this situation, the economic historian Alfred Chandler called the German dye companies the worlds first truly managerial industrial enterprises. With the world market for synthetic dyes and other chemical products dominated by the German industry, although cartels were attempted, they lasted at most for a few years. Others argued for the formation of a pool or Interessen-Gemeinschaft. In contrast, the chairman of Bayer, Carl Duisberg, argued for a merger. During a trip to the United States in the spring of 1903 he had visited several of the large American trusts such as Standard Oil, U. S. Steel, International Paper and Alcoa. In 1904, after having returned to Germany he proposed a merger of the producers of dye and pharmaceuticals in a memorandum to Gustav von Brüning. Hoechst and several pharmaceutical firms refused to join, instead, Hoechst and Cassella made an alliance based on mutual equity stakes in 1904
18.
Condensation polymer
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Types of condensation polymers include polyamides, polyacetals and polyesters. Condensation polymerization, a form of step-growth polymerization, is a process by which two molecules join together, resulting in loss of molecules which are often water. The type of end product resulting from a condensation polymerization is dependent on the number of end groups of the monomer which can react. Monomers with only one reactive group terminate a growing chain, linear polymers are created using monomers with two reactive end groups and monomers with more than two end groups give three-dimensional polymers which are crosslinked. Dehydration synthesis often involves joining monomers with an -OH group and a freely ionized -H on either end, normally, two or more different monomers are used in the reaction. The bonds between the group, the hydrogen atom and their respective atoms break forming water from the hydroxyl and hydrogen. Polyester is created through ester linkages between monomers, which involve the functional groups carboxyl and hydroxyl, nylon is another common condensation polymer. It can be manufactured by reacting di-amines with carboxyl derivatives, in this example the derivative is a di-carboxylic acid, but di-acyl chlorides are also used. Proteins are condensation polymers made from amino acid monomers, carbohydrates are also condensation polymers made from sugar monomers such as glucose and galactose. Condensation polymerization is used to form simple hydrocarbons. This method, however, is expensive and inefficient, so the polymer of ethene is generally used. Condensation polymers, unlike addition polymers, may be biodegradable, the peptide or ester bonds between monomers can be hydrolysed by acid catalysts or bacterial enzymes breaking the polymer chain into smaller pieces. The most commonly known condensation polymers are proteins, fabrics such as nylon, silk, biopolymer Polyester Polyamide Polymers - Virtual Text of Organic Chemistry, William Reusch
19.
Wallace Carothers
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Wallace Hume Carothers was an American chemist, inventor and the leader of organic chemistry at DuPont, credited with the invention of nylon. Carothers was a leader at the DuPont Experimental Station laboratory, near Wilmington, Delaware. Carothers was an organic chemist who, in addition to first developing nylon, after receiving his Ph. D. he taught at several universities before he was hired by DuPont to work on fundamental research. He married Helen Sweetman on February 21,1936, Carothers had been troubled by periods of depression since his youth. Despite his success with nylon, he felt that he had not accomplished much and had run out of ideas and his daughter, Jane, was born on November 27,1937. Carothers was born on April 27,1896 in Burlington, Iowa, to Ira and he was the oldest of four children. He had one brother and two sisters, John, Isobel and Elizabeth, as a youth, Carothers was fascinated by tools and mechanical devices and spent many hours experimenting. He attended public school in Des Moines, Iowa, where he was known as a conscientious student, in September 1915, he entered Tarkio College in Missouri. Although he initially majored in English, he switched to chemistry under the influence of Arthur Pardee and he graduated from Tarkio in 1920 at the age of 24 with a bachelor of science degree. Then he went to the University of Illinois for his master of arts degree, during the 1921–22 school year, Carothers held a one-year appointment as a chemistry instructor at the University of South Dakota. It was at the University of South Dakota that he began his independent research that resulted in an article accepted by the Journal of the American Chemical Society, in this paper he measured physical properties of phenylisocyanate and of diazobenzene-imide. He went back to the University of Illinois to study for his Ph. D. under Roger Adams and his degree was awarded in 1924. He specialized in organic chemistry and minored in chemistry and mathematics. He worked as an assistant during 1922–1923 and received the Carr Fellowship for 1923–24. This was the most prestigious award offered by the university at that time and he was initiated into Alpha Chi Sigma in 1926 as a member of Zeta Chapter at the University of Illinois. Carothers stayed at the University of Illinois for two years as an instructor in organic chemistry, in 1926 Carothers moved to Harvard University. Again he was an instructor in organic chemistry, conant, who became President of Harvard College in 1933, said of Carothers, In his research, Dr. Carothers showed even at this time the high degree of originality which marked his later work. He was never content to follow the path or to accept the usual interpretations of organic reactions
20.
Polyester
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Polyester is a category of polymers that contain the ester functional group in their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate, polyesters include naturally occurring chemicals, such as in the cutin of plant cuticles, as well as synthetics through step-growth polymerization such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not and this material is used very widely in clothing. Depending on the structure, polyester can be a thermoplastic or thermoset. There are also polyester resins cured by hardeners, however, the most common polyesters are thermoplastics, industrial polyester fibers, yarns and ropes are used in car tire reinforcements, fabrics for conveyor belts, safety belts, coated fabrics and plastic reinforcements with high-energy absorption. Polyester fiber is used as cushioning and insulating material in pillows, comforters, Polyester fabrics are highly stain-resistant— in fact, the only class of dyes which can be used to alter the color of polyester fabric are what are known as disperse dyes. Polyester fibers are spun together with natural fibers to produce a cloth with blended properties. Cotton-polyester blends can be strong, wrinkle and tear-resistant, and reduce shrinking, synthetic fibers in polyester also create materials with water, wind and environmental resistance compared to plant-derived fibers. Disadvantages of cotton and polyester blends include being less breathable than cotton and they are also less fire resistant and can melt when ignited. Polyester blends have been renamed so as to suggest their similarity or even superiority to natural fibers. Polyesters are also used to make bottles, films, tarpaulin, canoes, liquid crystal displays, holograms, filters, dielectric film for capacitors, film insulation for wire, polyesters are widely used as a finish on high-quality wood products such as guitars, pianos and vehicle/yacht interiors. Thixotropic properties of spray-applicable polyesters make them ideal for use on open-grain timbers, as they can quickly fill wood grain, cured polyesters can be sanded and polished to a high-gloss, durable finish. Liquid crystalline polyesters are among the first industrially used liquid crystal polymers and they are used for their mechanical properties and heat-resistance. These traits are important in their application as an abradable seal in jet engines. Polyesters as thermoplastics may change shape after the application of heat, while combustible at high temperatures, polyesters tend to shrink away from flames and self-extinguish upon ignition. Polyester fibers have high tenacity and E-modulus as well as low water absorption and they are used in the liquid state as casting materials, in sheet molding compounds, as fiberglass laminating resins and in non-metallic auto-body fillers. They are also used as the polymer matrix in pre-pregs. Fiberglass-reinforced unsaturated polyesters find wide application in bodies of yachts and as parts of cars
21.
World War II
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World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945, although related conflicts began earlier. It involved the vast majority of the worlds countries—including all of the great powers—eventually forming two opposing alliances, the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. Marked by mass deaths of civilians, including the Holocaust and the bombing of industrial and population centres. These made World War II the deadliest conflict in human history, from late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, and formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Poland, Finland, Romania and the Baltic states. In December 1941, Japan attacked the United States and European colonies in the Pacific Ocean, and quickly conquered much of the Western Pacific. The Axis advance halted in 1942 when Japan lost the critical Battle of Midway, near Hawaii, in 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained all of its territorial losses and invaded Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in South Central China and Burma, while the Allies crippled the Japanese Navy, thus ended the war in Asia, cementing the total victory of the Allies. World War II altered the political alignment and social structure of the world, the United Nations was established to foster international co-operation and prevent future conflicts. The victorious great powers—the United States, the Soviet Union, China, the United Kingdom, the Soviet Union and the United States emerged as rival superpowers, setting the stage for the Cold War, which lasted for the next 46 years. Meanwhile, the influence of European great powers waned, while the decolonisation of Asia, most countries whose industries had been damaged moved towards economic recovery. Political integration, especially in Europe, emerged as an effort to end pre-war enmities, the start of the war in Europe is generally held to be 1 September 1939, beginning with the German invasion of Poland, Britain and France declared war on Germany two days later. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or even the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred simultaneously and this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935. The British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the forces of Mongolia and the Soviet Union from May to September 1939, the exact date of the wars end is also not universally agreed upon. It was generally accepted at the time that the war ended with the armistice of 14 August 1945, rather than the formal surrender of Japan
22.
Toluene diisocyanate
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Toluene diisocyanate is an organic compound with the formula CH3C6H32. Two of the six isomers are commercially important,2, 4-TDI and 2. 2, 4-TDI is produced in the state, but TDI is often marketed as 80/20. It is produced on a scale, accounting for 34. 1% of the global isocyanate market in 2000. Approximately 1.4 billion kilograms were produced in 2000,2, 4-TDI is prepared in three steps from toluene via dinitrotoluene and 2, 4-diaminotoluene. Finally, the TDA is subjected to phosgenation, i. e. treatment with phosgene to form TDI and this final step produces HCl as a byproduct and is a major source of industrial hydrochloric acid. Distillation of the crude TDI mixture produces an 80,20 mixture of 2, 4-TDI and 2, 6-TDI, known as TDI. Differentiation or separation of the TDI can be used to produce pure 2, 4-TDI, the isocyanate functional groups in TDI react with hydroxyl groups to form carbamate links. The two isocyanate groups in TDI react at different rates, The 4-position is approximately four times more reactive than the 2-position,2, 6-TDI is a symmetrical molecule and thus has two isocyanate groups of similar reactivity, similar to the 2-position on 2, 4-TDI. However, since both groups are attached to the same aromatic ring, reaction of one isocyanate group will cause a change in the reactivity of the second isocyanate group. It is used in the production of polyurethane foams The LD50 for TDI is 5800 mg/kg for oral contact. Despite the indicated low toxicity, TDI is classified as “very toxic” by the European Community, in the United States, the Occupational Safety and Health Administration has set a permissible exposure limit with a ceiling at 0. This chemical was one of many that two massive explosions in a chemical warehouse stationed in Tianjin, China on August 13,2015. All major producers of TDI are members of the International Isocyanate Institute, whose aim is the promotion of the handling of TDI in the workplace, community
23.
Elastomer
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An elastomer is a polymer with viscoelasticity and very weak inter-molecular forces, generally having low Youngs modulus and high failure strain compared with other materials. The term, which is derived from elastic polymer, is used interchangeably with the term rubber. Each of the monomers which link to form the polymer is made of carbon. Elastomers are amorphous polymers existing above their glass transition temperature, so that considerable segmental motion is possible, at ambient temperatures, rubbers are thus relatively soft and deformable. Their primary uses are for seals, adhesives and molded flexible parts, application areas for different types of rubber are manifold and cover segments as diverse as tires, shoe soles, and dampening and insulating elements. The importance of rubbers can be judged from the fact that global revenues are forecast to rise to US$56 billion in 2020, Rubber like solids with elastic properties are called elastomers. Polymer chains are held together in elastomers by weakest intermolecular forces and this weak binding forces permit the polymers to be stretched. Natural rubber, neoprene rubber, buna-s and buna-n are elastomers, elastomers are usually thermosets but may also be thermoplastic. The long polymer chains cross-link during curing, i. e. vulcanizing, the molecular structure of elastomers can be imagined as a spaghetti and meatball structure, with the meatballs signifying cross-links. The elasticity is derived from the ability of the chains to reconfigure themselves to distribute an applied stress. The covalent cross-linkages ensure that the elastomer will return to its original configuration when the stress is removed, as a result of this extreme flexibility, elastomers can reversibly extend from 5-700%, depending on the specific material. Without the cross-linkages or with short, uneasily reconfigured chains, the stress would result in a permanent deformation. Temperature effects are present in the demonstrated elasticity of a polymer. It is also possible for a polymer to exhibit elasticity that is not due to covalent cross-links, butyl rubber Halogenated butyl rubbers Styrene-butadiene Rubber Nitrile rubber, also called Buna N rubbers Hydrogenated Nitrile Rubbers Therban and Zetpol. One should go through all differentiation while editing between Plastics and articles thereof and Rubber and articles thereof
24.
Hexamethylene diisocyanate
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Hexamethylene diisocyanate is an organic compound in the class known as isocyanates. More specifically, it is an aliphatic diisocyanate and it is produced in relatively small quantities, accounting for only 3. 4% of the global diisocyanate market in the year 2000. Aliphatic diisocyanates are used in applications, such as enamel coatings which are resistant to abrasion and degradation from ultraviolet light. These properties are desirable in, for instance, the exterior paint applied to aircraft
25.
1,4-Butanediol
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1, 4-Butanediol, colloquially known as BD, is the organic compound with the formula HOCH2CH2CH2CH2OH. It is a viscous liquid. It is one of four isomers of butanediol. In its industrial synthesis, acetylene reacts with two equivalents of formaldehyde to form 1, 4-butynediol and this type of acetylene-based process is illustrative of what is known as Reppe chemistry, after German chemist Walter Reppe. This route is used by BASF and Ashland/ISP, lyondellBasell manufactures 1, 4-butanediol in a multi-step process without the use of acetylene. First, propylene oxide is converted to allyl alcohol, the allyl alcohol is then hydroformylated to 4-hydroxybutyraldehyde. Hydrogenation of this aldehyde yields 1, 4-butanediol and it is also manufactured on an industrial scale from maleic anhydride in the Davy process, which is first converted to the methyl maleate ester, then hydrogenated. Other routes are from butadiene, allyl acetate and succinic acid, a biological route to BDO has been commerciallized that uses a genetically modified organism. 1, 4-Butanediol is used industrially as a solvent and in the manufacture of some types of plastics, elastic fibers, in organic chemistry,1, 4-butanediol is used for the synthesis of γ-butyrolactone. In the presence of acid and high temperature, it dehydrates to the important solvent tetrahydrofuran. At about 200 °C in the presence of soluble ruthenium catalysts, world production of 1, 4-butanediol was claimed to be about one million metric tons per year and market price is about 2,000 USD per ton. In 2013, worldwide production was claimed to be billions of lbs, almost half of it is dehydrated to tetrahydrofuran to make fibers such as Spandex. 1, 4-Butanediol is also used as a drug known by some users as One Comma Four, Liquid Fantasy. It exerts effects similar to γ-hydroxybutyrate, which is a product of 1. When mixed with other drugs, misuse of 1, 4-butanediol has resulted in addiction, while co-administration of ethanol and GHB already poses serious risks, co-administration of ethanol with 1, 4-butanediol will interact considerably and has many other potential risks. This is because the enzymes that are responsible for metabolizing alcohol also metabolize 1. 1, 4-Butanediol seems to have two types of pharmacological actions, One should note that the study arrived at this conclusion based on the finding that 1, 4-butanediol co-administered with ethanol led to potentiation of some of the behavioral effects of ethanol. However, potentiation of ethanols effects may simply be caused by competition for the alcohol dehydrogenase and acetaldehyde dehydrogenase enzymes with co-administered 1, the shared metabolic rate-limiting steps thus leads to slowed metabolism and clearance for both compounds including ethanols known toxic metabolite acetaldehyde
26.
DuPont
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In the 20th century, DuPont developed many polymers such as Vespel, neoprene, nylon, Corian, Teflon, Mylar, Kapton, Kevlar, Zemdrain, M5 fiber, Nomex, Tyvek, Sorona, Corfam, and Lycra. DuPont developed Freon for the refrigerant industry, and later more environmentally friendly refrigerants and it also developed synthetic pigments and paints including ChromaFlair. In 2014, DuPont was the fourth largest chemical company based on market capitalization. Its stock price is a component of the Dow Jones Industrial Average, DuPont was founded in 1802 by Éleuthère Irénée du Pont, using capital raised in France and gunpowder machinery imported from France. It began as a manufacturer of gunpowder, as du Pont noticed that the industry in North America was lagging behind Europe, the Eleutherian Mills site is now a museum and a National Historic Landmark. DuPont continued to expand, moving into the production of dynamite, in 1902, DuPonts president, Eugene du Pont, died, and the surviving partners sold the company to three great-grandsons of the original founder. Charles Lee Reese was appointed as director and the company began centralizing their research departments, the company subsequently purchased several smaller chemical companies, and in 1912 these actions gave rise to government scrutiny under the Sherman Antitrust Act. The courts declared that the dominance of the explosives business constituted a monopoly. The court ruling resulted in the creation of the Hercules Powder Company, at the time of divestment, DuPont retained the single base nitrocellulose powders, while Hercules held the double base powders combining nitrocellulose and nitroglycerine. DuPont subsequently developed the Improved Military Rifle line of smokeless powders, in 1910, DuPont published a brochure entitled Farming with Dynamite. DuPont also established two of the first industrial laboratories in the United States, where began the work on cellulose chemistry, lacquers. DuPont Central Research was established at the DuPont Experimental Station, across the Brandywine Creek from the powder mills. In 1914, Pierre S. du Pont invested in the automobile industry. The following year he was invited to sit on GMs board of directors, the DuPont company would assist the struggling automobile company further with a $25 million purchase of GM stock. In 1920, Pierre S. du Pont was elected president of General Motors, under du Ponts guidance, GM became the number one automobile company in the world. However, in 1957, because of DuPonts influence within GM, in the 1920s, DuPont continued its emphasis on materials science, hiring Wallace Carothers to work on polymers in 1928. Carothers invented neoprene, a rubber, the first polyester superpolymer. The invention of Teflon followed a few years later, DuPont introduced phenothiazine as an insecticide in 1935
27.
Polytetrahydrofuran
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Polytetrahydrofuran, also called poly glycol or poly, is a chemical compound with formula nOH2 or HO-n-H. It can be viewed as a polymer of tetrahydrofuran, or as the derived from 1. The product is available as polymers of low average molecular weights. In this form it is a waxy solid that melts between 20 and 30 °C. The commercial product can be processed further into polymers with molecular weights of 40,000, the product is sold under various trade names including Terathane from Invista and PolyTHF from BASF. The BASF plant in Ludwigshafen at one point was producing 250,000 metric tons per year, the main use of polytetrahydrofuran is to make elastic fibers such as spandex for stretchable fabrics and for polyurethane resins. The latter are polyurethane prepolymers dissolved in solvent and they are used in the manufacture of artificial leather. These elastomers are either made by reacting PTMEG with diisocyanates. Polytetrahydrofuran is commonly prepared by acid-catalyzed polymerization of tetrahydrofuran, the starting material is natural gas, which is converted to acetylene, then reacted with formaldehyde to make butynediol and then butanediol. The latter is turned into tetrahydrofuran by action of a catalyst and then polymerized
28.
BASF
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BASF SE is a German chemical company and the largest producer in the world. Its headquarters is located in Ludwigshafen, Germany, BASF has customers in over 200 countries and supplies products to a wide variety of industries. Despite its size and global presence, BASF has received little public attention since abandoning its consumer product lines in the 1990s. At the end of 2015, the company employed more than 122,000 people, in 2015, BASF posted sales of €70.4 billion and income from operations before special items of about €6.7 billion. The company is expanding its international activities with a particular focus on Asia. Between 1990 and 2005, the company invested €5.6 billion in Asia, for example in sites near Nanjing and Shanghai, China, BASF is listed on the Frankfurt Stock Exchange, London Stock Exchange, and Zurich Stock Exchange. The company delisted its ADR from the New York Stock Exchange in September 2007, the company is a component of the Euro Stoxx 50 stock market index. BASF was founded on 6 April 1865 in Mannheim, in the German-speaking country of Baden by Friedrich Engelhorn and it had been responsible for setting up a gasworks and street lighting for the town council in 1861. The gasworks produced tar as a byproduct, and Engelhorn used this for the production of dyes, BASF was set up in 1865 to produce other chemicals necessary for dye production, notably soda and acids. In 1866 the dye production processes were also moved to the BASF site, BASF recruited Heinrich Caro, a German chemist with experience of the dyestuffs industry in England, to be the first head of research. Caro developed a synthesis for alizarin, and applied for a British patent on 25 June 1869, coincidentally Perkin applied for a virtually identical patent on 26 June 1869, and the two companies came to a mutual commercial agreement about the process. In 1901, some 80% of the BASF production was dyestuffs, sodium carbonate was produced by the Leblanc process until 1880, when the much cheaper Solvay process became available. BASF ceased to make its own and bought it from the Solvay company thereafter, sulfuric acid was initially produced by the lead chamber process, but in 1890 a unit using the contact process was brought on stream, producing the acid at higher concentration and at lower cost. This followed extensive research and development by Rudolf Knietsch, for which he received the Liebig Medal in 1904, BASF also acquired and began mining anhydrite for gypsum at the Kohnstein in 1917. In 1925, BASF merged with Bayer, Hoechst and three companies to form I. G. Farben played a role in the Nazi economy. During World War II, the company manufactured poison gas, Zyklon B, used at camps and employed forced. Several company directors and senior managers were tried for war crimes and crimes against humanity, as a result of this monopoly, BASF was able to start operations at a new site in Leuna in 1916, where explosives were produced during the First World War
29.
Dow Chemical Company
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The Dow Chemical Co. commonly referred to as Dow, is an American multinational chemical corporation headquartered in Midland, Michigan, United States. As of 2007, it is the second-largest chemical manufacturer in the world by revenue and as of February 2009 and it ranked second in the world by chemical production in 2014. Dow manufactures plastics, chemicals, and agricultural products, with a presence in about 160 countries, it employs about 54,000 people worldwide. The company has seven different major operating segments, with a variety of products made by each one. Dows 2012 sales totaled approximately $57 billion, Dow has been called the chemical companies chemical company in that most of its sales are to other industries rather than end-users. Dow sells directly to end-users primarily in the human and animal health, Dow is a member of the American Chemistry Council. Dow is a producer of plastics, including polystyrene, polyurethane, polyethylene, polypropylene. It is also a producer of ethylene oxide, various acrylates, surfactants. It produces agricultural chemicals including the pesticide Lorsban and consumer products including Styrofoam, some Dow consumer products including Saran wrap, Ziploc bags and Scrubbing Bubbles were sold to S. C. Johnson & Son in 1997. Performance plastics make up 25 percent of Dows sales, with products designed for the automotive. The plastics include polyolefins such as polyethylene and polypropylene, as well as used to produce Styrofoam insulating material. Dow manufactures epoxy resin intermediates including bisphenol A and epichlorohydrin, major product lines include nitroparaffins, such as nitromethane, used in the pharmaceutical industry and manufactured by ANGUS Chemical Company, a wholly owned subsidiary of The Dow Chemical Co. Important polymers include Dowex ion exchange resins, acrylic and polystyrene latex, specialty chemicals are used as starting materials for production of agrochemicals and pharmaceuticals. Dow Water and Process Solutions is a unit which manufactures Filmtec reverse osmosis membranes which are used to purify water for human use in the Middle East. The technology was used during the 2000 Summer Olympics and 2008 Summer Olympics, agricultural Sciences provides 7 percent of sales and is responsible for a range of insecticides, herbicides and fungicides. Genetically modified plant seeds are also an important, growing area, Dow AgroSciences sells seeds commercially under the following brands, Mycogen, Atlas, PhytoGen and Hyland Seeds in Canada. Basic plastics end up in everything from diaper liners to beverage bottles, products are based on the three major polyolefins – polystyrene, polyethylene and polypropylene. Basic chemicals are used internally by Dow as raw materials and are sold worldwide
30.
Union Carbide
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Union Carbide Corporation is a wholly owned subsidiary of Dow Chemical Company. It currently employs more than 2,400 people, Union Carbide produces chemicals and polymers that undergo one or more further conversions by customers before reaching consumers. Some are high-volume commodities and others are specialty products meeting the needs of smaller markets, markets served include paints and coatings, packaging, wire and cable, household products, personal care, pharmaceuticals, automotive, textiles, agriculture, and oil and gas. The company is a component of the Dow Jones Industrial Average. Union Carbide was 50. 9% stakeholder in Union Carbide India Limited, before divesting them, the chemical giant owned consumer products Eveready and Energizer batteries, Glad bags and wraps, Simoniz car wax, and Prestone antifreeze. The company divested other businesses before being acquired by Dow Chemical on February 6,2001, including chemicals, polyurethane intermediates, industrial gases. In 1920 the company set up a division which manufactured ethylene glycol for use as automotive antifreeze. The company continued to acquire related chemical producers, including the Bakelite Corporation in 1939, the company changed its name to Union Carbide Corporation in 1957 and was often referred to as Carbide. It operated Oak Ridge National Laboratory from 1947 until the late 1970s, r&D activities has been centered at the Technical Center near Charleston, West Virginia. The Aerospace Materials Department was established for the mentioned purposes within the companys Carbon Products Division, ucar batteries was Carbides industrial and consumer zinc chloride battery business. The business including Energizer alkaline batteries was sold to Ralston Purina in 1986, after the Bhopal disaster, Union Carbide was the subject of repeated takeover attempts. In order to pay off its debt, Carbide sold many of its most familiar such as Glad Trashbags. Dow Chemical announced the purchase of Carbide in 1999 for $8.89 billion in stock, the Hawks Nest Tunnel disaster took place between 1927 and 1932 in a West Virginia tunnel project led by Union Carbide. During the construction of the tunnel, workers found the mineral silica and were asked to mine it for use in electroprocessing steel, the workers were not given masks or breathing equipment to use while mining. Due to silica dust exposure, many workers developed silicosis, a lung disease. According to a marker on site, there were 109 admitted deaths, a congressional hearing placed the death toll at 476. In the early 1960s, Union Carbide Corporation began mining a newly identified outcrop of chrysotile asbestos fibers near King City, the fibers were sold under the brand name Calidria, a combination of Cal and Idria. These fibers were sold in large quantities for a variety of purposes
31.
Monsanto
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Monsanto Company is a publicly traded American multinational agrochemical and agricultural biotechnology corporation. It is headquartered in Creve Coeur, Greater St. Louis, Monsanto is a leading producer of genetically engineered seed and Roundup, a glyphosate-based herbicide. Notable achievements by Monsanto include research on catalytic asymmetric hydrogenation and the first mass-produced light emitting diodes in addition to its work on genetic engineering, Monsanto was one of four groups to introduce genes into plants, and was among the first to conduct field trials of genetically modified crops. Monsanto was one of the first companies to apply the biotechnology industry business model to agriculture, in this business model, companies recoup R&D expenses by exploiting biological patents. Monsantos roles in agricultural changes, biotechnology products and lobbying of government agencies, the company once manufactured controversial products such as the insecticide DDT, PCBs, Agent Orange and recombinant bovine growth hormone. Its seed patenting model was criticized as biopiracy and a threat to biodiversity, in September 2016 Monsanto agreed to accept Bayers offer to purchase the company for $66 billion, pending regulatory approval. In 1901 Monsanto was founded in St. Louis, Missouri, the founder was John Francis Queeny, a 30‑year veteran of the nascent pharmaceutical industry. He funded the firm with his own money and capital from a soft drink distributor and he used his wifes maiden name for the company. The companys first products were commodity food additives, such as the sweetener saccharin, caffeine. Monsanto expanded to Europe in 1919 in a partnership with Graessers Chemical Works at Cefn Mawr, the venture produced vanillin, aspirin and its raw ingredient salicylic acid and later rubber processing chemicals. In the 1920s, Monsanto expanded into basic industrial chemicals such as sulfuric acid, queenys son Edgar Monsanto Queeny took over the company in 1928. In 1926 the company founded and incorporated a town called Monsanto in Illinois and it was formed to provide minimal regulation and low taxes for Monsanto plants at a time when local jurisdictions had most of the responsibility for environmental rules. It was renamed in honor of Leo Sauget, its first village president, in 1935, Monsanto bought the Swann Chemical Company in Anniston, Alabama, and thereby entered the business of producing PCBs. In 1936, Monsanto acquired Thomas & Hochwalt Laboratories in Dayton, Ohio, to acquire the expertise of Charles Allen Thomas, the acquisition became Monsantos Central Research Department. Thomas spent the rest of his career at Monsanto, serving as President and they urged Thomas to become co-director of the Manhattan Project at Los Alamos with Robert Oppenheimer, but Thomas was reluctant to leave Dayton and Monsanto. He joined the NDRC, and Monsantos Central Research Department began to conduct related research, to that end, Monsanto operated the Dayton Project, and later Mound Laboratories, and assisted in the development of the first nuclear weapons. In 1946, Monsanto developed and marketed All laundry detergent, which sold to Lever Brothers in 1957. In 1947, its factory was destroyed in the Texas City Disaster
32.
Bayer
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Bayer AG, German pronunciation, ) is a German multinational chemical, pharmaceutical and life sciences company. It is headquartered in Leverkusen, where its sign is a landmark. Bayers primary areas of business include human and veterinary pharmaceuticals, consumer products, agricultural chemicals and biotechnology products. The company is a component of the Euro Stoxx 50 stock market index, the companys motto is science for a better life. Bayers first and best known product was aspirin, there is a dispute about what scientist at Bayer made the most important contributions to it, Bayer trademarked the name heroin for the drug diacetylmorphine and marketed it as a cough suppressant and non-addictive substitute for morphine from 1898 to 1910. Bayer also introduced phenobarbital, prontosil, the first widely used antibiotic and the subject of the 1939 Nobel Prize in Medicine, the antibiotic Cipro, in 2014 Bayer bought MSDs consumer business, with brands such as Claritin, Coppertone and Dr. Scholls. Its BayerCropscience business develops genetically modified crops and pesticides and its materials science division makes polymers like polyurethanes and polycarbonate. Bayer was founded in Barmen in 1863 and it was part of IG Farben, the worlds largest chemical and pharmaceutical company, from 1925 to 1952, and then again became an independent company. The company played a key role in the Wirtschaftswunder during the early Cold War, Bayer acquired Schering in 2006 and announced its acquisition of Monsanto in 2016, the merger is still pending approval. Bayer AG was founded in Barmen, Germany in 1863 by Friedrich Bayer and his partner, the companys corporate logo, the Bayer cross, was introduced in 1904. It consists of the horizontal word BAYER crossed with the vertical word BAYER, an illuminated version of the logo is a landmark in Leverkusen, the location of Bayer AGs headquarters. Bayers first major product was acetylsalicylic acid, a modification of salicylic acid or salicin and it is now widely used in the US, UK, and France for all brands of the drug. However, it is still a trademark of Bayer in more than 80 other countries, including Canada, Mexico, Germany. As of 2011, approximately 40 thousand tons of aspirin are produced each year and 10 to 20 billion tablets are taken in the U. S. alone each year for prevention of cardiovascular events. It is on the WHO Model List of Essential Medicines, the most important medications needed in a health system. There has been controversy over the roles played by Bayer scientists in the development of aspirin, Arthur Eichengrün, a Bayer chemist, claimed to be the first to discover an aspirin formulation which did not have the unpleasant side effects of nausea and gastric pain. Eichengrün also claimed that he invented the name aspirin and was the first person to use the new formulation to test its safety, Bayer contends that aspirin was discovered by Felix Hoffmann to alleviate the sufferings of his father, who had arthritis. Various sources support the conflicting claims, most mainstream historians attribute the invention of aspirin to Felix Hoffmann and/or Arthur Eichengrün
33.
Chlorofluorocarbon
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A chlorofluorocarbon is an organic compound that contains only carbon, chlorine, and fluorine, produced as volatile derivative of methane, ethane, and propane. They are also known by the DuPont brand name Freon. The most common representative is dichlorodifluoromethane, many CFCs have been widely used as refrigerants, propellants, and solvents. As in simpler alkanes, carbon in the CFCs bonds with tetrahedral symmetry, because the fluorine and chlorine atoms differ greatly in size and effective charge from hydrogen and from each other, the methane-derived CFCs deviate from perfect tetrahedral symmetry. The physical properties of CFCs and HCFCs are tunable by changes in the number, in general they are volatile, but less so than their parent alkanes. The decreased volatility is attributed to the molecular polarity induced by the halides, thus, methane boils at −161 °C whereas the fluoromethanes boil between −51.7 and −128 °C. The CFCs have still higher boiling points because the chloride is even more polarizable than fluoride, because of their polarity, the CFCs are useful solvents, and their boiling points make them suitable as refrigerants. The densities of CFCs are higher than their corresponding alkanes, in general the density of these compounds correlates with the number of chlorides. CFCs and HCFCs are usually produced by halogen exchange starting from chlorinated methanes and ethanes, the chlorine atom, written often as Cl. behaves very differently from the chlorine molecule. The radical Cl. is long-lived in the atmosphere, where it catalyzes the conversion of ozone into O2. Ozone absorbs UV-B radiation, so its depletion allows more of high energy radiation to reach the Earths surface. Bromine atoms are more efficient catalysts, hence brominated CFCs are also regulated. Applications exploit the low toxicity, low reactivity, and low flammability of the CFCs and HCFCs, every permutation of fluorine, chlorine, and hydrogen based on methane and ethane has been examined and most have been commercialized. Furthermore, many examples are known for higher numbers of carbon as well as related compounds containing bromine, uses include refrigerants, blowing agents, propellants in medicinal applications, and degreasing solvents. Billions of kilograms of chlorodifluoromethane are produced annually as precursor to tetrafluoroethylene, chlorofluorocarbons, when derived from methane and ethane these compounds have the formulae CClmF4−m and C2ClmF6−m, where m is nonzero. Hydrofluorocarbons, when derived from methane, ethane, propane, and butane, these compounds have the respective formulae CFmH4−m, C2FmH6−m, C3FmH8−m, and C4FmH10−m, a numbering system is used for fluorinated alkanes, prefixed with Freon-, R-, CFC-, and HCFC-. The rightmost value indicates the number of atoms, the next value to the left is the number of hydrogen atoms plus 1. Thus, Freon-12 indicates a methane derivative containing two fluorine atoms and no hydrogen, another, easier equation that can be applied to get the correct molecular formula of the CFC/R/Freon class compounds is this to take the numbering and add 90 to it
34.
Methylene diphenyl diisocyanate
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Methylene diphenyl diisocyanate, most often abbreviated as MDI, is an aromatic diisocyanate. Three isomers are common, varying by the positions of the groups around the rings,2, 2-MDI,2, 4-MDI. The 4,4 isomer is most widely used, and is known as 4. This isomer is known as Pure MDI. MDI reacts with polyols in the manufacture of polyurethane and it is the most produced diisocyanate, accounting for 61. 3% of the global market in the year 2000. Total world production of MDI and polymeric MDI is over 5 million tonnes per year, the largest producer is Covestro followed closely by Yantai Wanhua. Other major producers are BASF, BorsodChem, Dow, Huntsman, Nippon Polyurethane Industry, all major producers of MDI are members of the International Isocyanate Institute, whose aim is the promotion of the safe handling of MDI and TDI in the workplace, community and environment. The isomer ratio is determined by the composition of the diamine. Distillation of the MDI mixture gives polymeric MDI and an MDI isomer mixture which has a low 2,4 isomer content, further purification entails fractionation of the MDI isomer mixture. The positions of the groups influences their reactivity. In 4, 4-MDI, the two groups are equivalent but in 2, 4-MDI the two groups display highly differing reactivities. The group at the 4-position is approximately four times more reactive than the group at the 2-position due to steric hindrance, the major application of 4, 4-MDI is the production of rigid polyurethane. Typically, one tonne of polyurethane foam needs 0.616 tonne of MDI and 0.386 tonne of polyol and these rigid polyurethane foams are good thermal insulators and used in nearly all freezers and refrigerators worldwide, as well as buildings. Typical polyols used are polyethylene adipate and poly glycol,4, 4-MDI is also used as an industrial strength adhesive, which is available to end consumers as various high-strength bottled glue preparations. MDI is the least hazardous of the commonly available isocyanates but is not benign and its very low vapour pressure reduces its hazards during handling compared to the other major isocyanates. However, it, like the other isocyanates, is an allergen, persons developing sensitivity to isocyanates may have dangerous systemic reactions to extremely small exposures, including respiratory failure. Handling MDI requires strict engineering controls and personal protective equipment, compared to other organic cyanates, MDI has a relatively low human toxicity. It is a potentially violently reactive material towards water and other nucleophiles
35.
Polyisocyanurate
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Polyisocyanurate, also referred to as PIR, polyiso, or ISO, is a thermoset plastic typically produced as a foam and used as rigid thermal insulation. Its chemistry is similar to polyurethane except that the proportion of methylene diphenyl diisocyanate is higher, catalysts and additives used in PIR formulations also differ from those used in PUR. The reaction of MDI and polyol takes place at higher temperatures compared with the temperature for the manufacture of PUR. At these elevated temperatures and in the presence of catalysts, MDI will first react with itself, producing a stiff, ring molecule. Remaining MDI and the tri-isocyanate react with polyol to form a poly polymer. PIR typically has an MDI/polyol ratio, also called its index, by comparison PUR indices are normally around 100. As the index increases material stiffness but also brittleness also increase, depending on the product application greater stiffness, chemical and/or thermal stability may be desirable. As such PIR manufacturers can offer multiple products with identical densities, PIR is typically produced as a foam and used as rigid thermal insulation. Its thermal conductivity has a value of 0.16 BTU*in/hr*ft2*°F depending on the perimeter. PIR foam panels laminated with pure embossed aluminium foil are used for fabrication of pre-insulated duct that is used for heating, ventilation and air conditioning systems. Prefabricated PIR sandwich panels are manufactured with corrosion-protected, corrugated steel facings bonded to a core of PIR foam and used extensively as roofing insulation, other typical uses for PIR foams include industrial and commercial pipe insulation, and carving/machining media. Effectiveness of the insulation of a building envelope can be compromised by gaps resulting from shrinkage of individual panels, manufacturing criteria require that shrinkage be limited to less than 1%. Multiple layers with staggered joints, ship lapped or tongue & groove joints greatly reduce these problems, PIR insulation can be a mechanical irritant to skin, eyes, and upper respiratory system during fabrication. Polyisocyanurate Insulation Manufacturers Association Polyisocyanurate Insulation energy savings, by Center for the Polyurethanes Industry
36.
Combustibility and flammability
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Combustibility is a measure of how easily a substance will set on fire, through fire or combustion. This is an important property to consider when a substance is used for construction or is being stored and it is also important in processes that produce combustible substances as a by-product. Special precautions are required for substances that are easily combustible. These measures may include installation of fire sprinklers or storage remote from possible sources of ignition, substances with low combustibility may be selected for construction where the fire risk needs to be reduced, such as apartment buildings, houses, or offices. If combustible resources are used there is chance of fire accidents. Fire resistant substances are preferred for building materials and furnishings, for an Authority Having Jurisdiction, combustibility is defined by the local code. BS 476-4,1970 defines a test for combusibility in which 3 specimens of a material are heated in a furnace, otherwise, the material shall be deemed combustible. Various countries have tests for determining noncombustibility of materials, most involve the heating of a specified quantity of the test specimen for a set duration. Usually, the material cannot support combustion and must not undergo a loss of mass. In Canada, for instance, firewalls must be made of concrete, in building construction, buildings are typically divided into combustible and noncombustible ones. Combustible structures have more stringent limits on building height and area. A number of industrial processes produce combustible dust as a by-product, the most common being wood dust. In addition to wood, combustible dusts include metals, especially magnesium, titanium and aluminum, there are at least a 140 known substances that produce combustible dust. While the particles in a combustible dusts may be of any size, as of 2012, the United States Occupational Safety and Health Administration has yet to adopt a comprehensive set of rules on combustible dust. When suspended in air, the particles of combustible dust present a potential for explosions. Accumulated dust, even when not suspended in air, remains a fire hazard, collectors designed to reduce airborne dust account for more than 40 percent of all dust explosions. Other important processes are grinding and pulverizing, transporting powders, filing silos and containers, investigation of 200 dust explosions and fires, between 1980 to 2005, indicated approximately 100 fatalities and 600 injuries. In January 2003, a powder explosion and fire at the West Pharmaceutical Services plant in Kinston, North Carolina resulted in the deaths of six workers
37.
Thermoplastic
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A thermoplastic, or thermosoftening plastic, is a plastic material, a polymer, that becomes pliable or moldable above a specific temperature and solidifies upon cooling. Most thermoplastics have a molecular weight. The polymer chains associate through intermolecular forces, which weaken rapidly with increased temperature, thermoplastics differ from thermosetting polymers, which form irreversible chemical bonds during the curing process. Thermosets do not melt, but decompose and do not reform upon cooling, above its glass transition temperature and below its melting point, the physical properties of a thermoplastic change drastically without an associated phase change. Some thermoplastics do not fully crystallize below the transition temperature. Amorphous and semi-amorphous plastics are used when high optical clarity is necessary, amorphous and semi-amorphous plastics are less resistant to chemical attack and environmental stress cracking because they lack a crystalline structure. Brittleness can be decreased with the addition of plasticizers, which increases the mobility of amorphous chain segments to effectively lowers the transition temperature. Modification of the polymer through copolymerization or through the addition of side chains to monomers before polymerization can also lower it. Naval Research Laboratory developed thermoplastic armor, that can be repaired in the field by a user via tools for pressing irons, acrylic, a polymer called poly, is also known by trade names such as Lucite, Perspex and Plexiglas. It serves as a substitute for glass for items such as aquariums, motorcycle helmet visors, aircraft windows, viewing ports of submersibles. It is extensively used to make signs, including lettering and logos, in medicine, it is used in bone cement and to replace eye lenses. Acrylic paint consists of PMMA particles suspended in water, acrylonitrile butadiene styrene is a terpolymer synthesized from styrene and acrylonitrile in the presence of polybutadiene. ABS is a material that exhibits high impact resistance and mechanical toughness. It poses few risks to health under normal handling. It is used in consumer products, such as toys, appliances. Nylon belongs to a class of polymers called polyamides and it has served as a substitute mainly for hemp, cotton and silk, in products such as parachutes, cords, sails, flak vests and womens clothing. Nylon fibers are useful in making fabrics, rope, carpets and musical strings, whereas in bulk form, Nylon is used for mechanical parts including machine screws, gears, in addition, it is used in the manufacture of heat-resistant composite materials. Polylactic acid is a biodegradable thermoplastic aliphatic polyester derived from renewable resources, such as starch, tapioca roots, chips or starch
38.
Mica
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The mica group of sheet silicate minerals includes several closely related materials having nearly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition, the nearly perfect cleavage, which is the most prominent characteristic of mica, is explained by the hexagonal sheet-like arrangement of its atoms. The word mica is derived from the Latin word mica, meaning a crumb, and probably influenced by micare, to glitter. Chemically, micas can be given the general formula X2Y4–6Z8O204 in which X is K, Na, or Ca or less commonly Ba, Rb, or Cs, Y is Al, Mg, or Fe or less commonly Mn, Cr, Ti, Li, etc. Z is chiefly Si or Al, but also may include Fe3+ or Ti, structurally, micas can be classed as dioctahedral and trioctahedral. If the X ion is K or Na, the mica is a common mica, whereas if the X ion is Ca, mica is widely distributed and occurs in igneous, metamorphic and sedimentary regimes. Large crystals of mica used for various applications are typically mined from granitic pegmatites, until the 19th century, large crystals of mica were quite rare and expensive as a result of the limited supply in Europe. However, their price dramatically dropped when large reserves were found and mined in Africa, the largest documented single crystal of mica was found in Lacey Mine, Ontario, Canada, it measured 10 ×4.3 ×4.3 m and weighed about 330 tonnes. Similar-sized crystals were found in Karelia, Russia. The British Geological Survey reported that as of 2005, Koderma district in Jharkhand state in India had the largest deposits of mica in the world. China was the top producer of mica with almost a third of the share, closely followed by the US, South Korea. Large deposits of mica were mined in New England from the 19th century to the 1970s. Large mines existed in Connecticut, New Hampshire, and Maine, scrap and flake mica is produced all over the world. In 2010, the producers were Russia, Finland, United States, South Korea, France. The total production was 350,000 t, although no data were available for China. Most sheet mica was produced in India and Russia, flake mica comes from several sources, the metamorphic rock called schist as a byproduct of processing feldspar and kaolin resources, from placer deposits, and from pegmatites. Sheet mica is considerably less abundant than flake and scrap mica, the most important sources of sheet mica are pegmatite deposits. Sheet mica prices vary with grade and can range from less than $1 per kilogram for low-quality mica to more than $2,000 per kilogram for the highest quality, the mica group represents 37 phyllosilicate minerals that have a layered or platy texture
39.
Thermal expansion
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Thermal expansion is the tendency of matter to change in shape, area, and volume in response to a change in temperature. Temperature is a function of the average molecular kinetic energy of a substance. When a substance is heated, the energy of its molecules increases. Thus, the molecules begin vibrating/moving more and usually maintain an average separation. Materials which contract with increasing temperature are unusual, this effect is limited in size, the degree of expansion divided by the change in temperature is called the materials coefficient of thermal expansion and generally varies with temperature. If an equation of state is available, it can be used to predict the values of the expansion at all the required temperatures and pressures. A number of contract on heating within certain temperature ranges. For example, the coefficient of expansion of water drops to zero as it is cooled to 3. Also, fairly pure silicon has a coefficient of thermal expansion for temperatures between about 18 and 120 Kelvin. Unlike gases or liquids, solid materials tend to keep their shape when undergoing thermal expansion, in general, liquids expand slightly more than solids. The thermal expansion of glasses is higher compared to that of crystals, at the glass transition temperature, rearrangements that occur in an amorphous material lead to characteristic discontinuities of coefficient of thermal expansion and specific heat. These discontinuities allow detection of the transition temperature where a supercooled liquid transforms to a glass. Absorption or desorption of water can change the size of common materials. Common plastics exposed to water can, in the long term, the coefficient of thermal expansion describes how the size of an object changes with a change in temperature. Specifically, it measures the change in size per degree change in temperature at a constant pressure. Several types of coefficients have been developed, volumetric, area, which is used depends on the particular application and which dimensions are considered important. For solids, one might only be concerned with the change along a length, the volumetric thermal expansion coefficient is the most basic thermal expansion coefficient, and the most relevant for fluids. In general, substances expand or contract when their temperature changes, substances that expand at the same rate in every direction are called isotropic
40.
Pontiac Fiero
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The Pontiac Fiero is a mid-engined sports car built by Pontiac from 1983 to 1988. The Fiero was designed by George Milidrag and Hulki Aldikacti as a sports car, the Fiero was the first two-seater Pontiac since the 1926 to 1938 coupes, and also the first and only mass-produced mid-engine sports car by a U. S. manufacturer. Many technologies incorporated in the Fiero design such as body panels were radical for their time. Other features included hidden headlamps and, initially, integrated stereo speakers within the driver and passenger headrests. A total of 370,168 Fieros were produced over the short production run of five years. At the time, its reputation suffered from criticisms over performance, the word fiero means very proud in Italian, and wild, fierce, or ferocious in Spanish. Alternative names considered for the car were Sprint, P3000, Pegasus, Fiamma, Sunfire, the Fiero 2M4 was on Car and Driver magazines Ten Best list for 1984. The 1984 Fiero was the Official Pace Car of the Indianapolis 500 for 1984, the Fiero was conceived as a small, two-seat sports car with all new suspension and V6 engine. These figures are U. S. Environmental Protection Agency test-circuit results, published by Pontiac and it was impressive mileage for a 2.5 L engine of the period, and still good by todays standards, but the three-speed automatic reduced highway mileage to only 32 mpg‑US. With respect to economy, the Fiero was intended to appeal to a market niche for which the Corvette with its V8 engine was unsuitable. A mid-engine layout was chosen as a way to reduce both aerodynamic drag and vehicle weight to improve fuel efficiency, and also for its handling, traction. However, the sports car potential of the layout was not realized when the Fiero debuted. As a cost-saving measure commonly employed at GM, the tires, brakes, as a result, the handling and cornering abilities of the initial Fiero were merely on par with other contemporary sporty coupes. As drivers attempted to run the engine at greater RPM than it was designed for. The public had high expectations for the Fiero with its layout and aggressive styling. While initially garnering good reviews for its handling, the Fiero soon received negative reviews from automotive critics who expected higher performance from a mid-engine two-seater. Despite the critical press, the Fiero sold well and although Pontiac operated three shifts at the factory during 1984, they could not keep up with initial demand. The front suspension was derived from the Chevette, and Chevette enthusiasts found that they could upgrade their undersized front brakes, by 1985, the oil crisis was long past and demand developed for a Fiero having more engine power and better sports car performance
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