Synthesis and properties of poly(butylene succinate) with N‐hexenyl side branches

N ‐hexenyl side branches were introduced into poly(butylene succinate) (PBS) by polymerization of succinic acid (SA) with 1,4‐butanediol (BD) in the presence of 7‐octene‐1,2‐diol (OD). Thermal properties and biodegradability of the aliphatic polyesters were investigated before and after epoxidation of the pendant double bonds. The glass‐transition temperature ( T g ) decreased with the branching density to give a minimum at 0.03 mol of branching units per mole of structural units. Thereafter, T g increased due to the in situ crosslinking of the unsaturated groups during the differential scanning calorimetry (DSC) measurements. N ‐Hexenyl side branches decreased melting temperature ( T m ) more significantly than ethyl side branches, but the effect was on par with that by n ‐octyl branches. Epoxidation of the double bonds decreased T m and melting enthalpy (Δ H m ), but increased T g of the aliphatic polyester. Biodegradability was enhanced to some extent by the presence of n ‐hexenyl side branches. However, the epoxidation of the unsaturated groups did not notably affect the biodegradability.