Polyaddition of Bifunctional Isoprene Prepolymer Terminated with Hydroxy Groups and Diisocyanates

Abstract

Isoprene prepolymer having hydroxy groups at their both ends were synthesized in about 75% yields by the solution polymerization of isoprene initiated by sodium naphthalene to living prepolymers, with subsequent treating with dry oxygen stream. Molecular weights of these prepolymers are 1300–1500 and numbers of hydroxy groups are 2.0–2.15 per one molecule. The polyaddition reaction of isoprene prepolymers having hydroxy groups and diisocyanates was also investigated. Besides of anisole, as the reaction medium, N,N-dimethyformamide and dimethyl sulfoxide can be used. The polymer thus obtained was yellow sponge rubber-like and insoluble in common organic solvents. The glass transition temperature of the polymer which synthesized by the methyl (S)-2,6-diisocyanatohexanoate was 73–78 °C.