|Catalytic Hydrogenation of Diene Rubber and Thermoplastic Elastomer by
Transition Metal and Higher Functioning of the Polymer
Synthetic Rubber Development Department, ASAHI KASEI CHEMICALS, Co., Kawasaki, Kanagawa, Japan
Nippon Gomu Kyokaishi,(2008),81(10),438-444 General Review in Japanese
Several properties and performances of diene rubber and thermoplastic elastomer are improved by catalytic hydrogenation. Generally, heat resistance and weatherability are extremely improved, and polarity, crystallinity and molecular mobility, etc. can be varied after hydrogenation.
Homogeneous catalyst is often used for the hydrogenation of the polydiene because of the higher activity than heterogeneous one, into which the polymer diffusion is rate-determining. Homogeneous catalysts for the hydrogenation of polydiene are roughly classified into three types, (1) Ziegler type (organic-Ni,Co),(2) Metallocen type (Ti),(3) Organo-noble metal type (Rh,Pd,Ru). Although the total number of published reports for the hydrogenation catalyst has been a little decreasing in recent these years, the supported-noble metal type (heterogeneous catalyst) is getting popular recently due to the catalyst recyclability.
Titanocene shows high selectivity for the hydrogenation of 1,2-bond in polybutadiene. Taking advantage of this phenomenon, the selective hydrogenation for rubber and elastomer grade has been developed for the applications of a PP-modification, a pressure sensitive adhesive and a low rolling resistance tire material.
Catalytic Hydrogenation, Transition Metal, Diene, Rubber, Elastomer