The effect of molecular weight on thermal properties and degradation behavior of copolymers based on TMC and DTC

Abstract A series of copolymers [P (TMC-co-DTC)] with different molecular weights based on trimethylene carbonate (TMC) and 2, 2′-dimethyltrimethylene carbonate (DTC) were synthesized via ring-opening copolymerization, by adjusting the amount of Sn(Oct)2. The thermal performance showed that the Tg and Td of the obtained amorphous copolymer rose with the increase of molecular weight from 118 to 213 kDa. Then the in vitro enzymatic experiment was carried out in lipase solutions, it could be concluded that the higher the molecular weight, the faster the degradation rate of the P (TMC-co-DTC), which may be related to the stronger hydrophobicity of the high molecular weight sample. Furthermore, the degradation mechanism of P (TMC-co-DTC) was determined to be the surface erosion, due to the result of the unchanged molecular weight during the degradation period. The fact that polycarbonate copolymer produces no acidic compounds in the process of enzymatic degradation had also been confirmed. This study provides confirmation for adjusting the degradation behavior performance of polycarbonate materials by molecular weight to meet the needs of more abundant clinical applications.