Synthesis, Chain Extension and Enzymatic Degradation of Aliphatic-Based Polyesters Containing an Aromatic Unit

Abstract

The synthesis, chain extension, and enzymatic degradation of aliphatic-based polyesters containing an aromatic unit were carried out in the present study. The polyesters were initially prepared by the polycondensation of diesters [aliphatic dimethyl adipate (DMA) and aromatic dimethyl terephthalate (DMT)] with 1, 4-butanediol (BD) using the Ti (O-i-Pr) 4 catalyst. The polyesters with number-average molecular weights (Mn) of 10, 00016, 000 were obtained in good yields. Melting temperatures (Tm) of DMT/DMA/BD polyesters with DMT content>ca. 40mol% (viz., DMT/DMA≥40/60) considerably exceeded that of the DMA/BD polyester. To obtain higher molecular weight polymers, chain extension reactions of the polyesters were carried out using hexamethylene diisocyanate (HDI) as a chain extender. Mn of chain extended polyesters consequently increased 24 times as much. The mechanical (here, tensile) properties of chain extended polyesters, particularly at DMT content of 40mol%, improved very much. The enzymatic degradation of the polyesters by lipoprotein lipase decreased with DMT content, though degradation proceeded slowly but steadily.