Preparation of thermal plastic polyurethane-polystyrene block copolymer via UV irradiation polymerization

A facile method is described for preparing thermal plastic polyurethane-polystyrene (PUPS) block copolymer. 2-Hydroxy-2-methyl-1-phenyl-1-propanone (HMPP)-capped polyurethane was synthesized and used as macrophotointiator to prepare PUPS by ultraviolet (UV) irradiation polymerization of styrene. The polymerization process of PUPS block copolymer was monitored by real-time FTIR, 1 H NMR, and GPC, which confirmed the conversion of styrene and formation of PUPS block copolymer. The influence of reaction temperature on styrene conversion was investigated and the results demonstrated the feasibility of preparation of PUPS block copolymer by UV polymerization at ambient temperature. The DSC and TG data revealed a new glass transition temperature and degradable step respectively for PUPS block copolymer induced by polystyrene block compared with neat polyurethane and polyurethane macrophotoinitiator, which further clarified the formation of PUPS block copolymer. The properties measurements showed that the prepared PUPS block copolymer exhibited better tensile strength, hardness and water-resistance than neat polyurethane.