Reactivity and microstructure in the epoxidation of polybutadiene

Abstract

We investigated the epoxidation of polybutadiene (PB) by peroxy acid generated in situ. Four types of polybutadienes were epoxidized by formic acid–hydrogen peroxide system. The micro structure of each is as follows: (cis%) PB-1(98), (cis:trans:vinyl(pendant)%) PB-2 (9:85:6), PB-4(36:55:9), (cis:vinyl(pendant)%)) PB-3(10:90). The reactivity of the double bond decreased in the following order; trans cis vinyl(pendant). The selectivity of epoxidation decreased as follows; cis vinyl(pendant) trans. The double bonds of PB-1 reacted quantitatively, and the selectivity of the formation of epoxide group was 74%. The ring opening of epoxide group obtained from trans-double bond in PB-2 occurred quickly by reaction with formic acid. The reactivity of PB-3 was lower than that of PB-1, because of the less-substituted double bond. PB-4 showed the same reactivity as PB-1, but gelation was observed when 60% of the double bonds reacted. Thus, we could obtain the product with well-defined structure by reaction of PB with a clearly determined micro structure. This method (formic acid–hydrogen peroxide system) was effective for the functionalization of PB. © 1994, The Society of Polymer Science, Japan. All rights reserved.