POLYMERIZATION AND DEGRADATION OF 1,5-DIOXEPAN-2-ONE

1,5-Dioxepan-2-one was polymerized with stannous 2-ethylhexanoate as initiator and gave high molecular weight polymers, with MW > 150,000. The highest molecular weight was achieved at 110-degrees-C, and full conversion was reached after 20 hours. The polymerization rate increased with temperature. Transesterfication reactions and thermal degradation occurred above 130-degrees-C, which led to a decrease of the molecular weight. Polymerization with anion and cationic initiators led to low molecular weight polymers. Degradation of poly(1,5-dioxepan-2-one) took place by the hydrolysis of ester bonds, and the initial molecular weight decreased by 30% during 46 weeks, starting from MW = 45,000.