Design and Synthesis of New Biodegradable Copolyesters

Abstract

To develop new useful biodegradable polymers from easily available raw materials, various copolyesters were designed and synthesized, and their properties and biodegradability were evaluated. Triblock copolymers, PLLA-b-P(CL-r-DLLA)-b-PLLA, consisting of poly(L-lactide)(PLLA)and poly(ε-caprolactone-r-DL-lactide)(P(CL-r-DLLA))blocks, showed excellent properties as thermoplastic elastomers. Triblock copolymers consisting of PLLA and aliphatic polyesters synthesized by the polycondensation of 3-methyl-1,3-propanediol and aliphatic dicarboxylic acids showed high biodegradability in seawater. Sequence-controlled copolyesters composed of terephthalic acid, ethylene glycol, and hydroxy acid such as glycolic acid and L-lactic acid with high melting point and biodegradability in seawater were developed. Sequence-controlled poly(ester-amide)s composed of diol, dicarboxylic acid, and γ-aminobutyric acid components showed improved thermal stability compared to polyamide 4, and the poly(ester-amide)s containing short diols and aliphatic dicarboxylic acids showed high biodegradability.