Japanese Buddhist architecture
Japanese Buddhist architecture is the architecture of Buddhist temples in Japan, consisting of locally developed variants of architectural styles born in China. After Buddhism arrived the continent via Three Kingdoms of Korea in the 6th century, an effort was made to reproduce original buildings as faithfully as possible, but local versions of continental styles were developed both to meet Japanese tastes and to solve problems posed by local weather, more rainy and humid than in China; the first Buddhist sects were Nara's six Nanto Rokushū, followed during the Heian period by Kyoto's Shingon and Tendai. During the Kamakura period, in Kamakura were born the Jōdo and the native Japanese sect Nichiren-shū. At the same time Zen Buddhism arrived from China influencing all other sects in many ways, including architecture; the social composition of Buddhism's followers changed radically with time. In the beginning it was the elite's religion, but it spread from the noble to warriors, merchants and to the population at large.
On the technical side, new woodworking tools like the framed pit saw and the plane allowed new architectonic solutions. Buddhist temples and Shinto shrines share their basic characteristics and differ only in details that the non-specialist may not notice; this similarity is because the sharp division between Buddhist temples and Shinto shrines is recent, dating to the Meiji period's policy of separation of Buddhism and Shinto of 1868. Before the Meiji Restoration it was common for a Buddhist temple to be built inside or next to a shrine, or for a shrine to include Buddhist sub-temples. If a shrine housed a Buddhist temple, it was called a jingū-ji. Analogously, temples all over Japan used to adopt tutelary kami (chinju and built shrines within their precincts to house them. After the forcible separation of temples and shrines ordered by the new government, the connection between the two religions was severed, but continued nonetheless in practice and is still visible today. Buddhist architecture in Japan during the country's whole history has absorbed much of the best available natural and human resources.
Between the 8th and the 16th centuries, it led the development of new structural and ornamental features. For these reasons, its history is vital to the understanding of not only Buddhist architecture itself, but of Japanese art in general. Buddhist architecture in Japan is not native, but was imported from China and other Asian cultures over the centuries with such constancy that the building styles of all Six Dynasties are represented, its history is as a consequence dominated by Chinese and other Asian techniques and styles on one side, by Japanese original variations on those themes on the other. Due to the variety of climates in Japan and the millennium encompassed between the first cultural import and the last, the result is heterogeneous, but several universal features can nonetheless be found. First of all is the choice of materials, always wood in various forms for all structures. Unlike both Western and some Chinese architecture, the use of stone is avoided except for certain specific uses, for example temple podia and pagoda foundations.
The general structure is always the same: columns and lintels support a large and curved roof, while the walls are paper-thin movable and in any case non-carrying. Arches and barrel roofs are absent. Gable and eave curves are gentler than in columnar entasis limited; the roof is the most visually impressive component constituting half the size of the whole edifice. The curved eaves extend far beyond the walls, covering verandas, their weight must therefore be supported by complex bracket systems called tokyō; these oversize eaves give the interior a characteristic dimness, which contributes to the temple's atmosphere. The interior of the building consists of a single room at the center called moya, from which sometimes depart other less important spaces, for example corridors called hisashi. Inner space divisions are fluid, room size can be modified through the use of screens or movable paper walls; the large, single space offered by the main hall can therefore be altered according to the need.
The separation between inside and outside is itself in some measure not absolute as entire walls can be removed, opening the temple to visitors. Verandas appear to be part of the building to an outsider, but part of the external world to those in the temple. Structures are therefore made to a certain extent part of their environment; the use of construction modules keeps proportions between different parts of the edifice constant, preserving its overall harmony. In cases as that of Nikkō Tōshō-gū, where every available space is decorated, ornamentation tends to follow, therefore emphasize rather than hide, basic structures. Being shared by both sacred and profane architecture, these architectonic features made it easy converting a lay building into a temple; this happened for example at Hōryū-ji, where a noblewoman's mansion was transformed into a religious building. Buddhism is not a Japanese native religion, its architecture arrived from the continent via Korea together with the first Buddhists in the 6th century.
Adopted in the wake of the Battle of Shigisan in 587, after that date Buddhist temples began to be constructed. Because of the hostility of supporters of local kami beliefs towards Buddhism, no temple of that period survives, so we don't know what they were like
Tokyo Tokyo Metropolis, one of the 47 prefectures of Japan, has served as the Japanese capital since 1869. As of 2018, the Greater Tokyo Area ranked as the most populous metropolitan area in the world; the urban area houses the seat of the Emperor of Japan, of the Japanese government and of the National Diet. Tokyo forms part of the Kantō region on the southeastern side of Japan's main island and includes the Izu Islands and Ogasawara Islands. Tokyo was named Edo when Shōgun Tokugawa Ieyasu made the city his headquarters in 1603, it became the capital after Emperor Meiji moved his seat to the city from Kyoto in 1868. Tokyo Metropolis formed in 1943 from the merger of the former Tokyo Prefecture and the city of Tokyo. Tokyo is referred to as a city but is known and governed as a "metropolitan prefecture", which differs from and combines elements of a city and a prefecture, a characteristic unique to Tokyo; the 23 Special Wards of Tokyo were Tokyo City. On July 1, 1943, it merged with Tokyo Prefecture and became Tokyo Metropolis with an additional 26 municipalities in the western part of the prefecture, the Izu islands and Ogasawara islands south of Tokyo.
The population of the special wards is over 9 million people, with the total population of Tokyo Metropolis exceeding 13.8 million. The prefecture is part of the world's most populous metropolitan area called the Greater Tokyo Area with over 38 million people and the world's largest urban agglomeration economy; as of 2011, Tokyo hosted 51 of the Fortune Global 500 companies, the highest number of any city in the world at that time. Tokyo ranked third in the International Financial Centres Development Index; the city is home to various television networks such as Fuji TV, Tokyo MX, TV Tokyo, TV Asahi, Nippon Television, NHK and the Tokyo Broadcasting System. Tokyo third in the Global Cities Index; the GaWC's 2018 inventory classified Tokyo as an alpha+ world city – and as of 2014 TripAdvisor's World City Survey ranked Tokyo first in its "Best overall experience" category. As of 2018 Tokyo ranked as the 2nd-most expensive city for expatriates, according to the Mercer consulting firm, and the world's 11th-most expensive city according to the Economist Intelligence Unit's cost-of-living survey.
In 2015, Tokyo was named the Most Liveable City in the world by the magazine Monocle. The Michelin Guide has awarded Tokyo by far the most Michelin stars of any city in the world. Tokyo was ranked first out of all sixty cities in the 2017 Safe Cities Index; the QS Best Student Cities ranked Tokyo as the 3rd-best city in the world to be a university student in 2016 and 2nd in 2018. Tokyo hosted the 1964 Summer Olympics, the 1979 G-7 summit, the 1986 G-7 summit, the 1993 G-7 summit, will host the 2019 Rugby World Cup, the 2020 Summer Olympics and the 2020 Summer Paralympics. Tokyo was known as Edo, which means "estuary", its name was changed to Tokyo when it became the imperial capital with the arrival of Emperor Meiji in 1868, in line with the East Asian tradition of including the word capital in the name of the capital city. During the early Meiji period, the city was called "Tōkei", an alternative pronunciation for the same characters representing "Tokyo", making it a kanji homograph; some surviving official English documents use the spelling "Tokei".
The name Tokyo was first suggested in 1813 in the book Kondō Hisaku, written by Satō Nobuhiro. When Ōkubo Toshimichi proposed the renaming to the government during the Meiji Restoration, according to Oda Kanshi, he got the idea from that book. Tokyo was a small fishing village named Edo, in what was part of the old Musashi Province. Edo was first fortified in the late twelfth century. In 1457, Ōta Dōkan built Edo Castle. In 1590, Tokugawa Ieyasu was transferred from Mikawa Province to Kantō region; when he became shōgun in 1603, Edo became the center of his ruling. During the subsequent Edo period, Edo grew into one of the largest cities in the world with a population topping one million by the 18th century, but Edo was Tokugawa's home and was not capital of Japan. The Emperor himself lived in Kyoto from 794 to 1868 as capital of Japan. During the Edo era, the city enjoyed a prolonged period of peace known as the Pax Tokugawa, in the presence of such peace, Edo adopted a stringent policy of seclusion, which helped to perpetuate the lack of any serious military threat to the city.
The absence of war-inflicted devastation allowed Edo to devote the majority of its resources to rebuilding in the wake of the consistent fires and other devastating natural disasters that plagued the city. However, this prolonged period of seclusion came to an end with the arrival of American Commodore Matthew C. Perry in 1853. Commodore Perry forced the opening of the ports of Shimoda and Hakodate, leading to an increase in the demand for new foreign goods and subsequently a severe rise in inflation. Social unrest mounted in the wake of these higher prices and culminated in widespread rebellions and demonstrations in the form of the "smashing" of rice establishments. Meanwhile, supporters of the Meiji Emperor leveraged the disruption that t
Daibutsuyō is a Japanese religious architectural style which emerged in the late 12th or early 13th century. Together with Wayō and Zenshūyō, it is one of the three most significant styles developed by Japanese Buddhism on the basis of Chinese models. Called tenjikuyō, because it had nothing to do with India it was rechristened by scholar Ōta Hirotarō during the 20th century, the new term stuck. Ōta derived the name from Chōgen's work Tōdai-ji's Daibutsuden. Soon abandoned after its creator's death because it didn't harmonize with Japanese tastes, it nonetheless influenced other building styles with its rational solutions; the combination of wayō and daibutsuyō in particular became so frequent that sometimes it is classed separately by scholars under the name Shin-wayō. This grandiose and monumental style is the antithesis of the traditional wayō style; the Nandaimon at Tōdai-ji and the Amida-dō at Jōdo-ji in Ono are its best extant examples. The style was introduced by priest Chōgen, who in 1180 directed the reconstruction of Tōdai-ji, destroyed during the Genpei war.
Chōgen had just come back from the last of his three travels to China and therefore chose as a basis for the work Song Dynasty architecture. He was supported in his innovative work by first shōgun Minamoto no Yoritomo. Of his work at the temple only three structures remain, the mentioned Nandaimon, which remains the best Daibutsuyō example, the Kaizandō and the Hokkedō; the gate's most characteristic features are the six-tier bracket groups projecting directly out of the columns and connected to each other by ties as long as the facade. During the Edo period the temple's Main Hall, the Daibutsuden, was rebuilt in the style, to which it would give its name. Chōgen built other buildings in this style near and around Nara, of which the Amida-dō at Jōdo-ji in Ono is a good extant example; the style declined after its creator's death because it did not agree with Japanese tastes. Structural elements are treated as design elements, the building's deliberate roughness is supposed to be part of its beauty, but the concept was too alien to Chōgen's contemporaries, was rejected.
The Daibutsuyō style was short-lived but innovative, many of the ideas it introduced were adopted by other styles as well. In particular, during the Muromachi period the traditional Wayō style was so influenced that the mix of the two is sometimes called Shin-wayō. Thick woodwork and imposing general look Use of penetrating tie beamsDuring the Heian period temples were built using only non-penetrating tie beams made to fit around columns and pillars and nailed; the daibutsuyō style and the zenshūyō style replaced them with penetrating tie-beams, which pierced the column, were therefore much more effective against earthquakes. The nageshi was however retained as a purely decorative element. Thick, visible structural elements with decorative functionAs mentioned, many structural elements are left uncovered and have a decorative function. For example, the roof's supporting members are not covered by a ceiling and are therefore visible from within the temple; the Nandaimon's stabilizing bracket ties which run the entire width of the gate are fully visible.
Structural elements are much thicker than in Zen buildings. SashihijikiThe sashihijiki is a bracket arm inserted directly into a pillar instead of resting onto a supporting block on top of a pillar, as was normal in the preceding wayō style. At Tōdai-ji, both the Nandaimon and the Daibutsuden have six sashihijiki one on top of the other.. ŌgidarukiAnother detail unique to this style are the ōgidaruki. The rafters supporting each roof corner spread in a fan-like pattern. KibanaThe tips of each protruding beam ends in a nose-like structure called kibana. Japanese Buddhist architecture - Heian period Wayō Setchūyō Zenshūyō Fletcher, Sir Banister. Sir Banister Fletcher's a history of architecture. Architectural Press. ISBN 0-7506-2267-9. Retrieved 2009-11-11. "JAANUS". Japanese Architecture and Art Net Users System. Nishi, Kazuo. What is Japanese architecture?. Kodansha International. ISBN 4-7700-1992-0. Retrieved 2009-11-11. Young, David. Introduction to Japanese architecture. Periplus Asian architecture. Tuttle Publishing.
ISBN 0-7946-0100-6. Retrieved 2010-01-11
Minka are vernacular houses constructed in any one of several traditional Japanese building styles. In the context of the four divisions of society, minka were the dwellings of farmers and merchants; this connotation no longer exists in the modern Japanese language, any traditional Japanese-style residence of an appropriate age could be referred to as minka. Minka are characterised by their roof structure and their roof shape. Minka developed through history with distinctive styles emerging in the Edo period; the term minka means "houses of the people". It covers houses that accommodated a wide variety of people from farmers to village headmen and low level samurai. Minka come in a wide range of styles and sizes as a result of differing geographic and climatic conditions as well as the lifestyle of the inhabitants, they fall into one of four classifications: farmhouses nōka town houses machiya, fishermen's dwellings gyoka and mountain dwellings sanka. Unlike other forms of Japanese architecture, it is the structure rather than the plan, of primary importance to the minka.
Minka are divided up with primary posts that form the basic framework and bear the structural load of the building. Despite the wide variety of minka, there are eight basic forms. The'inverted U' consists of two vertical posts fixed at the top with a horizontal beam; the beam can be fixed to the top of the post either by resting upon it or via a mortise and tenon joint. This latter method is found in minka on the island of Shikoku. The'ladder' has post and beam units connected with larger beams including beams that are closer to the foundation level; this form of structure originated in townhouses of the Edo period. The system allows the irregular placement of posts and, allows flexibility in the plan. With the'umbrella' style, four beams radiate out from a central post; these posts sit at the centre of the square rather than the corners. Minka of this type are found in Shiga Prefecture. The'cross' has two beams at right angles to one another with the posts in the centre of the sides, it is used for small minka that have no other posts erected in the space or for large minka in the earth-floored area.
The style is most found in Shiga and Fukui prefectures.'Parallel crosses' are found in Shizuoka Prefecture and cover an area 5 metres by 10 metres. This system doubles up the ` cross' structure with eight posts; the ` box' structure connects four or more beam units to create a box-like structure. It can be found in Toyama and Ishikawa prefectures. The'interconnected box' can be found in Kyoto and Osaka.'Rising beams' is a form that enables better use of the second storey. It uses beams that rise from the posts to a secondary ridge, below the one formed by the rafters. Thatched roof farmhouses based upon the'rising beam' structure can be further classified into four major types; the yojiro-gumi and the wagoya are rare. The latter of these, the wagoya, is popular for machiya houses. Far more common are the odachi types; the odachi style has rafters and short vertical posts to support the ridge. These posts would have extended to the ground resulting in a row of posts extending down the centre of the house and dividing it.
Although these could be accommodated in the layout of the main house, they were impractical in the earth-floored entrance area—so they were omitted and a special beam structure used instead. This style was in wide use until the Edo period; the sasu style is a simpler triangular shape with a pair of rafters joined at the top to support the ridge pole. The ends of these rafters were sharpened to fit into mortice holes at either end of crossbeam; as this system does not rely on central posts it leaves a more unobstructed plan than the odachi style. There were two main methods for setting out the floor plan of the minka; the kyoma method uses a standard size of tatami mat, whereas the inakama method is based upon column spacing. The kyoma method works well for minka without central columns as the mats and the sliding partitions can be based on a standard size, it was used in minka in eastern Japan. The method has its disadvantages if used with posts because variations in post width can make the prefabrication of the sliding partitions difficult.
The inakama method is based upon the distance between centre of one post and centre of the post adjacent to it and it was used on the eastern side of Japan. The size and decoration of a minka was dependent upon its location and social status of its owner. Minka were influenced by local building techniques and were built with materials that were abundant in the immediate locality. For example, minka in Shizuoka used abundant bamboo for roofs, eaves and floors; when miscanthus reeds were difficult to obtain for thatched roofs, shingles were used instead. Climate had a bearing on construction: In Kyoto in the late Heian and Muromachi periods, roofs were clad in thin wooden shingles so owners would put stones on top to prevent the shingles from flying away in the wind; the social status of the minka owner was indicated by the complexity of the building. For thatched roof minka the nu
A dōjō is a hall or space for immersive learning or meditation. This is traditionally in the field of martial arts, but has been seen in other fields, such as meditation and software development; the term means "place of the Way" in Japanese. The word dōjō originates from Buddhism. Dōjō were adjunct to temples and were formal training place for any of the Japanese arts ending in "-dō", from the Chinese Tao, meaning "way" or "path". Sometimes meditation halls where Zen Buddhists practice zazen meditation were called dōjō; the alternative term zen-do is more specific, more used. European Sōtō Zen groups affiliated with the International Zen Association prefer to use dōjō instead of zendo to describe their meditation halls as did their founding master, Taisen Deshimaru. In Japan, any facility for physical training, including professional wrestling, may be called a dōjō. In the Western world, the term dōjō is used for Japanese martial arts such as aikidō, judō, karate-dō, etc. In American culture, the dojo was popularized by a young Jon Pep.
This is the origin of the phrase “sweep the leg Johnny”. A proper Japanese martial arts dōjō is well cared for by its users. Shoes are not worn in a dōjō. In many styles it is traditional to conduct a ritual cleaning of the dōjō at the beginning and/or end of each training session. Besides the obvious hygienic benefits of regular cleaning it serves to reinforce the fact that dōjō are supposed to be supported and managed by the student body, not the school's instructional staff; this attitude has become lost in many modern dōjō that are founded and run by a small group of people or instructors. In fact, it is not uncommon that in traditional schools, dōjō are used for training at all, instead being reserved for more symbolic or formal occasions; the actual training is conducted outdoors or in a less formal area. Many traditional dōjō follow a prescribed pattern with shomen and various entrances that are used based on student and instructor rank laid out precisely. Students will enter in the lower-left corner of the dōjō with instructors in the upper right corner.
Shomen contains a Shintō shrine with a sculpture, flower arrangement, or other artifacts. The term kamiza means "place of honor" and a related term, kamidana refers to the shrine itself. Other artifacts may be displayed throughout the dōjō, such as kanban that authorize the school in a style or strategy, items such as taiko drums or armor, it is not uncommon to find the name of the dōjō and the dōjō kun displayed prominently at shomen as well. Visitors may have a special place reserved, depending on their station. Weapons and other training gear will be found on the back wall. A honbu dōjō is the central training facility and administrative headquarters of a particular martial arts style; some well-known dōjō located in Japan are: Kodokan Judo Institute Aikikai Hombu Dōjō Noma Dōjō Nakazato Karate Weapons Gym Other names for training halls that are equivalent to "dojo" include the following: Akhara Dojang Gelanggang Heya Kalari Sasaran Wuguan The term dōjō is increasingly used for other forms of immersive-learning space.
The term dōjō is sometimes used to describe the meditation halls where Zen Buddhists practice zazen meditation. The alternative term zen-do is more specific, more used. European Sōtō Zen groups affiliated with the International Zen Association prefer to use dōjō instead of zendo to describe their meditation halls as did their founding master, Taisen Deshimaru. Coding dōjō: a space and associated technique for groups to practice computer programming skills Testing dōjō: a space and time where testers work together on a testing challenge Agile coaching dōjō: a space where a cross-functional team works for up to three months, surrounded by an agile coach and technical subject matter experts, to learn and practice agile and technical practices
East Asian hip-and-gable roof
In East Asian architecture, the hip-and-gable roof consists of a hip roof that slopes down on all four sides and integrates a gable on two opposing sides. It is constructed with two large sloping roof sections in the front and back while each of the two sides is constructed with a smaller roof section; the style has spread across East Asia. The original style and similar styles are found in the traditional architecture of Japan, Vietnam, Tibet, Sri Lanka and Kalmykia, it influenced the style of the bahay na bato of the Philippines. It is known as xiēshān in Chinese, irimoya in Japanese, paljakjibung in Korean. Irimoya arrived from China to Japan in the 6th century; the style was used in the main and lecture halls of a Buddhist temple compound. It started to be used for the honden at shrines during the Japanese Middle Ages, its gable is right above the moya, or core, while the hip covers the hisashi, a veranda-like aisle surrounding the core on one or more sides. It is still in wide use in Buddhist temples and Shinto shrines in Japan, in palaces and folk dwellings.
In the last case, it is called moya-zukuri. In Sri Lanka, a style known as the Kandyan roof bears many similarities to the original East Asian hip-and-gable roof; the Kandyan roof is used for religious, royal buildings. Its roots however lie in the traditions of the "Sri Lankan village". Gablet roof
Polystyrene is a synthetic aromatic hydrocarbon polymer made from the monomer styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear and rather brittle, it is an inexpensive resin per unit weight. It is a rather poor barrier to oxygen and water vapour and has a low melting point. Polystyrene is one of the most used plastics, the scale of its production being several million tonnes per year. Polystyrene can be transparent, but can be coloured with colourants. Uses include protective packaging, lids, trays, disposable cutlery and in the making of models; as a thermoplastic polymer, polystyrene is in a solid state at room temperature but flows if heated above about 100 °C, its glass transition temperature. It becomes rigid; this temperature behaviour is exploited for extrusion and for molding and vacuum forming, since it can be cast into molds with fine detail. Polystyrene is slow to biodegrade, it is accumulating as a form of litter in the outdoor environment along shores and waterways in its foam form, in the Pacific Ocean.
Polystyrene was discovered in 1839 by an apothecary from Berlin. From storax, the resin of the American sweetgum tree Liquidambar styraciflua, he distilled an oily substance, a monomer that he named styrol. Several days Simon found that the styrol had thickened into a jelly he dubbed styrol oxide because he presumed an oxidation. By 1845 Jamaican-born chemist John Buddle Blyth and German chemist August Wilhelm von Hofmann showed that the same transformation of styrol took place in the absence of oxygen, they called the product "metastyrol". In 1866 Marcelin Berthelot identified the formation of metastyrol/Styroloxyd from styrol as a polymerisation process. About 80 years it was realized that heating of styrol starts a chain reaction that produces macromolecules, following the thesis of German organic chemist Hermann Staudinger; this led to the substance receiving its present name, polystyrene. The company I. G. Farben began manufacturing polystyrene in Ludwigshafen, about 1931, hoping it would be a suitable replacement for die-cast zinc in many applications.
Success was achieved when they developed a reactor vessel that extruded polystyrene through a heated tube and cutter, producing polystyrene in pellet form. In 1941, Dow Chemical invented a Styrofoam process. Before 1949, chemical engineer Fritz Stastny developed pre-expanded PS beads by incorporating aliphatic hydrocarbons, such as pentane; these beads are the raw material for extruding sheets. BASF and Stastny applied for a patent, issued in 1949; the moulding process was demonstrated at the Kunststoff Messe 1952 in Düsseldorf. Products were named Styropor; the crystal structure of isotactic polystyrene was reported by Giulio Natta. In 1954, the Koppers Company in Pittsburgh, developed expanded polystyrene foam under the trade name Dylite. In 1960, Dart Container, the largest manufacturer of foam cups, shipped their first order. In chemical terms, polystyrene is a long chain hydrocarbon wherein alternating carbon centers are attached to phenyl groups. Polystyrene's chemical formula is n; the material's properties are determined by short-range van der Waals attractions between polymers chains.
Since the molecules consist of thousands of atoms, the cumulative attractive force between the molecules is large. When heated, the chains are able to take on a higher degree of conformation and slide past each other; this intermolecular weakness confers elasticity. The ability of the system to be deformed above its glass transition temperature allows polystyrene to be softened and molded upon heating. Extruded polystyrene is about as strong as an unalloyed aluminium but much more flexible and much less dense. Polystyrene results. In the polymerisation, the carbon–carbon π bond of the vinyl group is broken and a new carbon–carbon σ bond is formed, attaching to the carbon of another styrene monomer to the chain; the newly formed σ bond is stronger than the π bond, broken, thus it is difficult to depolymerize polystyrene. About a few thousand monomers comprise a chain of polystyrene, giving a molecular weight of 100,000–400,000; each carbon of the backbone has tetrahedral geometry, those carbons that have a phenyl group attached are stereogenic.
If the backbone were to be laid as a flat elongated zig-zag chain, each phenyl group would be tilted forward or backward compared to the plane of the chain. The relative stereochemical relationship of consecutive phenyl groups determines the tacticity, which has an effect on various physical properties of the material; the diastereomer where all of the phenyl groups are on the same side is called isotactic polystyrene, not produced commercially. The only commercially important form of polystyrene is atactic, in which the phenyl groups are randomly distributed on both sides of the polymer chain; this random positioning prevents the chains from aligning with sufficient regularity to achieve any crystallinity. The plastic has a glass transition temperature Tg of ~90 °C. Polymerisation is initiate