Three kinds of polyurethane-polyvinyl thermoplastic elastomers were synthesized by the combination of a two-step synthesis and chain polymerization. Their structures were confirmed by FT-IR and H-1 NMR, and their properties were also characterized. X-ray diffraction studies showed semicrystalline patterns for this type of copolymers. Tensile properties indicated that the copolymers had smaller extensibilities than typical polyurethanes. Thermogravimetric analysis curves displayed a better thermal stability for the copolymers due to their longer hard segments and the 1,1,2,2-tetraphenyl-1,2-ethanediol component. Differential scanning calorimetry studies and dynamic mechanical analysis revealed that this type of copolymers had microphase-separated structures and possessed elastomeric properties. (C) 2000 Elsevier Science Ltd. All rights reserved.