Synthesis of poly[(5-benzyloxy-trimethylene carbonate)-co-(5,5-dimethyl-trimethylene carbonate)] catalyzed by immobilized lipase on silica particles with different size

Porcine pancreas lipase (PPL) immobilized on silica particles with different size were prepared and employed successfully for ring-opening co-polymerization of 5-benzyloxy-trimethylene carbonate (BTMC) with 5,5-dimethyl-trimethylene carbonate (DTC) for the first time. Three kinds of silica particles with different sizes (150-250, 75-150 and 1 μm) were selected as carriers for enzyme immobilization. The structure of copolymers were confirmed by ¹H and ¹³C NMR which showed no decarboxylation occurrence during the polymerization. The (M_n) of poly(BTMC-co-DTC) decreased rapidly with the increasing of immobilized PPL concentration. The carrier size of immobilized PPL affected both the catalytic activity and the polymer yield. The highest molecular weight (M_n=26,400) of poly(BTMC-co-DTC) was obtained at around 0.1% concentration of immobilized PPL on silica particles with size of 75-150 μm.