Properties and biodegradation of poly(ethylene adipate) and poly(butylene succinate) containing styrene glycol units

Mechanical and thermal properties together with biodegradability of poly(butylene succinate) (PBS) and poly(ethylene adipate) (PEA) were investigated when phenyl branches were introduced into the aliphatic polyesters by copolymerizing styrene glycol with the diacids and the diols. Increasing content of styrene glycol units decreased Tm, crystallinity and molecular weight of the aliphatic copolyesters, which concurrently decreased the tensile properties. Tg was raised from −47°C for PEA to 30°C for poly(styrene succinate). The copolyesters containing higher content of sytrene glycol units were mineralized faster into CO2 in the modified Sturm test. However, the rate of bond cleavage by an abiotic hydrolysis was nearly independent of the presence of styrene glycol units.