Polyterpenes

Polyterpenes are polymers derived from terpenes, most commonly polymers of isoprene, known as polyisoprenes. In nature, polyterpenes occur as major elastomeric polymers, notably natural rubber, which is cis-1,4-polyisoprene produced by Hevea brasiliensis and related species, and other plant sources. Gutta-percha and balata are also polyterpenes based on 1,4-polyisoprene but with different stereochemistry, giving greater rigidity.

The structure of polyterpenes depends on the linkage geometry. Polymerization of isoprene yields 1,4-linkages; the cis configuration imparts elasticity, while trans linkages yield a stiffer material. The overall properties are influenced by cis/trans content, molecular weight, tacticity, and crosslinking. In nature, rubber is mostly cis, contributing to high elasticity, whereas gutta-percha is predominantly trans and more rigid.

Industrial production of polyterpenes includes the synthesis of polyisoprene from isoprene by emulsion or solution polymerization, using a range of catalysts. Properties can be tuned by controlling molecular weight and microstructure; vulcanization with sulfur or other crosslinkers further enhances strength and elasticity.

Applications include tires, seals, hoses, medical gloves, and other elastomer components. Historically, gutta-percha was used for underwater cables and dental materials. Research into polyterpenes also explores bio-based monomers from other terpenes and blends with natural rubber to improve sustainability and performance.