Synthesis of poly(ester-urethane)s from hydroxytelechelic polylactide: Effect of initiators on their physical and degradation properties

A series of poly(l-lactide)-based poly(ester-urethane)s (PEUs) were synthesized by ring-opening polymerization of l-lactide using a variety of diols such as diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol (TetraEG), 1,5-pentanediol (PD), 1,8-octanediol (OD), isopropyl tartrate (TRAiPr) and benzyl tartrate (TRABn) in the presence of Sn(Oct)2, followed by chain extension with hexamethylene diisocyanate (HMDI). The thermal, mechanical, and degradation properties of the resulting PEUs were studied. The crystallinities of the PEUs decreased with increasing diol contents and were also dependent on the kind of the diol unit. The degradabilities of the PEUs with proteinase K were effectively controlled by the kind of diol unit depending on their size and hydrophilicity. The biodegradation of the PEUs in compost also showed strong dependence on the diol units in the PEUs in spite of relatively low diol content (∼3%).