Pine resin

In polymer chemistry and materials science, resin is a "solid or highly viscous substance" of plant or synthetic origin that is typically convertible into polymers. They are often mixtures of organic compounds, principally terpenes. Many plants, particularly woody plants, produce resin in response to injury. The resin acts as a bandage protecting the plant from invading insects and pathogens.

Plants secrete resins and rosins for their protective benefits. They confound a wide range of herbivores, insects, and pathogens, while the volatile phenolic compounds may attract benefactors such as parasitoids or predators of the herbivores that attack the plant.

The resin produced by most plants is composed mainly of terpenes and derivatives. The most common terpenes in resin are the bicyclic terpenes alpha-pinene, beta-pinene, delta-3 carene, and sabinene, the monocyclic terpenes limonene and terpinolene, and smaller amounts of the tricyclic sesquiterpenes, longifolene, caryophyllene and delta-cadinene. Some resins also contain a high proportion of resin acids. The individual components of resin can be separated by fractional distillation. Rosins on the other hand are less volatile and consist, inter alia, of diterpenes.

Notable examples of plant resins include amber, Balm of Gilead, balsam, Canada balsam, Boswellia, copal from trees of Protium copal and Hymenaea courbaril, dammar gum from trees of the family Dipterocarpaceae, Dragon's blood from the dragon trees (Dracaena species), elemi, frankincense from Boswellia sacra, galbanum from Ferula gummosa, gum guaiacum from the lignum vitae trees of the genus Guaiacum, kauri gum from trees of Agathis australis, hashish (Cannabis resin) from Cannabis indica, labdanum from mediterranean species of Cistus, mastic (plant resin) from the mastic tree Pistacia lentiscus, myrrh from shrubs of Commiphora, sandarac resin from Tetraclinis articulata, the national tree of Malta, styrax (a Benzoin resin from various Styrax species), Spinifex resin from Australian Spinifex grasses, and turpentine, distilled from pine resin.

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