In polymer chemistry and materials science, a resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses mainly on naturally occurring resins.
Insect trapped in resin
Cedar of Lebanon cone showing flecks of resin as used in the mummification of Egyptian Pharaohs
Extremely viscous resin extruding from the trunk of a mature Araucaria columnaris.
The material dripping from an almond tree looks confusingly like resin, but actually is a gum or mucilage, and chemically very different.
Terpenes are a class of natural products consisting of compounds with the formula (C5H8)n for n ≥ 2. Terpenes are major biosynthetic building blocks. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. In plants, terpenes and terpenoids are important mediators of ecological interactions, while some insects use some terpenes as a form of defense. Other functions of terpenoids include cell growth modulation and plant elongation, light harvesting and photoprotection, and membrane permeability and fluidity control.
Many terpenes are derived commercially from conifer resins, such as those made by this pine.
Second- or third-instar caterpillars of Genus Papilio butterflies, like this Papilio glaucus, emit terpenes from their osmeterium.