Study on Comparison of Continuous and Pulse Microwave Irradiation in Synthesis of Poly(D,L-lactide)

摘要

Poly(D,L-lactide) (PDLLA) with good biodegradability and biocompatibility is confined in large scale production by high energy consumption and low production yield. In this study, continuous microwave irradiation and pulse microwave irradiation were adopted in the preparation of PDLLA by ring-opening polymerization (ROP) of D,L-lactide (DLLA), with stannous octoate (Sn(Oct)2) as catalyst, to reduce energy consumption. Under 10 min of 90 W continuous microwave irradiation, PDLLA with viscosity average molecular weight (M |? ) of 15.92×10 4 g mol -1 and yield of 81.8% was obtained from 1.5 g DLLA. The results demonstrate that continuous microwave irradiation can significantly shorten the ROP time of DLLA and consequently decrease the expended energy. The comparative study also reveales that continuous microwave irradiation has incomparable advantages over pulse microwave irradiation, say nothing of conventional heating, and therefore is preferred in industrial production of PDLLA.