the present disclosure is directed to polymer blends comprising a biopolymer and a substituted or unsubstituted aliphatic polyester . the aliphatic polyester comprises repeating units derivable from a substituted or unsubstituted aliphatic diacid , repeating units derivable from a substituted or unsubstituted aliphatic diol , and one or two terminator units derivable from a substituted or unsubstituted aliphatic alcohol . the polymer blends disclosed herein provide improved flexibility , and are useful , for example , in the production of packaging materials , industrial products , durable goods , and the like .