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A High Efficiency PDMS-Based Stabilizer for Dispersion Polymerization of L-lactide in Supercritical Carbon Dioxide

Dispersion polymerization of lactides and lactones has been studied and has received a great deal of attention used to prepare biodegradable polymers in supercritical carbon dioxide (ScCO2). The triblock copolymers of poly(ϵ-caprolactone) PCL-polydimethylsiloxane (PDMS)-poly(ϵ-caprolactone) PCL by the feed ratio of 1:2:1 and 1:3:1, respectively were synthesized to be used as the stabilizers in the dispersion polymerization of L-lactide. The fine poly(L-lactide) (PLLA) powders were obtained at the concentrations of 3% to 5%w/w (stabilizer/monomer). The results demonstrated that the triblock copolymers were the effective stabilizers for the dispersion polymerization of L-lactide. It was also found that the cooling process had a significant effect on the particle size of the fine powders. In order to obtain the best PLLA powders, it would be necessary to use the cooling process with stirring.