Copolymerization of poly(butylene succinate) with 3-alkoxy-1,2-propanediols

A copolymer of poly(butylene succinate) was produced from dimethyl succinate (1), 1,4-butanediol (2) and 3-alkoxy-1,2-propanediol (3) such as 3-methoxy-1, 2-propanediol (3a), 3-allyloxy-1, 2-propanediol (3b) and 3-octadecyloxy-1, 2-propanediol (3c). Copolymers of high molecular weight were obtained when a small amount of 3 was included, but molecular weight decreased with increasing amount of 3. Copolymers including a small amount of 3 had larger break strain than homopolymer. Although the copolymer including 0.3% 3c possessing an alkyl long chain had the largest break strain, copolymers including more amount of 3c had lower molecular weights and lower break strain because of the low reactivity of secondary alcohol of 3c. To accelerate copolymerization a new method was designed in which diols of 3c are first esterified by succinic anhydride and then copolymerization. When 0-5 mol% of 3c was used in copolymerization by the method, copolymers with M. higher than 60000 were obtained. The copolymer including 5 mol% of 3c showed break stress reached of 833%, and the biodegradation rate of the copolymer was slower than homopolymer.