Polyaddition of Bifunctional Isoprene Prepolymer Terminated with Hydroxy Groups and Diisocyanates

Hiroaki KOUZAI* and Takashi MITSUMATA

Department of Industrial Chemistry, College of Engineering, Kanto Gakuin University; 1-50-1 Mutsuura-higashi, Kanazawa-ku, Yokohama-shi 236-8501 Japan

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.

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