Telechelic diols from polyhydroxybutyrate via alcoholysis with ethylene glycol or glycerol

摘要

Controlled degradation of poly-hydroxybutyrate (PHB) can be obtained by alcoholysis with two types of alcohol in the presence of p-toluenesulfonic acid as catalyst. PHB oligomers terminated with free hydroxyl groups were prepared in this way and characterized using NMR, DSC and TG analyses. The degradation proceeds by random chain scission and the molecular weight was decreased by almost two orders of magnitude. The melting temperature, T_m, and the degradation temperature (T_d) of PHB after alcoholysis, investigated by differential scanning calorimetry (DSC) and TG analyses show a decrease in T_m and T_d with decreased molecular weight. Oligomers terminated with free reactive hydroxyl groups and T_m decreased by approximately 22°C are liable to be used in the next step for further modification.