Preparation of monodisperse polylactide microspheres by dispersion polymerization using a polymeric stabilizer with hydroxy groups

Monodisperse poly(D,L-lactide) (PDLLA) microspheres have been prepared by dispersion polymerization of D,L-lactide with a synthetic polymeric stabilizer. The polymerization is carried out in xylene/heptane (1:2, v/v) at 368 K for 3 h with poly[(dodecyl methacrylate)-co-(2- hydroxyethyl methacrylate)] (P(DMA-co-HEMA)). P(DMA-co-HEMA) has hydroxy groups as an initiation group for pseudoanionic dispersion polymerization. The particle diameter and the coefficient of variation concerning the diameter distribution of the obtained PDLLA microspheres are 3.9 μm and 4.3%, respectively. In addition, from the results of dynamic light scattering measurements, it is found that P(DMA-co-HEMA) and the PDLLA-grafted copolymer form a micellar structure in solution.