Synthesis of biodegradable diblock copolymers of glycolide and poly(oxyethylene) using a montmorillonite clay as catalyst

Biodegradable diblock copolymers were prepared from glycolide and poly(oxyethylene) of M-n = 600 (POE 600), 1500 (POE 1500) and 2000 (POE 2000). The copolymerization of glycolide and POE was induced in heterogeneous phase by "Maghnite-H+" under suitable conditions. Maghnite-H+ is a montmorillonite sheet silicate clay exchanged with protons. Various techniques, including H-1 NMR, C-13 NMR, IR, DSC and Ubbelohde viscometer were used to elucidate structural characteristics and thermal properties of the resulting copolymers. The effect of the [glycolide]/[POE] molar ratio on the rate of copolymerization and on intrinsic viscosity of the resulting copolymers was studied. Data showed that the rate of copolymerization and intrinsic viscosity of copolymers increase with increasing [glycolide]/[POE) molar ratio.