Published: December 1972
For many years natural rubber has been known to consist mainly of hydrocarbon chains in which isoprene units are linked together in a regular cis-1,4 molecular structure. Another natural product, gutta percha, is also known to be a polymer of isoprene, but one having a trans-1,4 structure. The synthesis of polyisoprene by isoprene polymerization had been a goal of chemists for nearly a hundred years, when success in preparing it was announced by three research groups--at Goodrich, Firestone, and Goodyear --all within the same year, 1955.
This report is concerned with isoprene polymerization to produce cis-1,4 polyisoprene, the synthetic "natural" rubber (IR). Two solution type processes are evaluated. One uses a Ziegler type catalyst, and the other uses a lithium alkyl catalyst.
The present report also includes a description and evaluation of a process for converting synthetic cis-1,4 polyisoprene into a latex. Synthetic latices can be prepared that have properties and applications very similar to those of natural rubber latices.
The industry status section is based on U.S. Tariff Commission reports and trade and technical journals. The review of chemistry is based on technical journals as well as reference books. Process information was derived from technical journals, patents, technical bulletins, and reference books.