A novel approach to the preparation of thermoplastic polyurethane elastomer and polyamide 6 blends by in situ anionic ring-opening polymerization of ε-caprolactam

Blends of thermoplastic polyether-based urethane elastomer (TPEU) and monomer casting polyamide 6 (MCPA6) were prepared using epsilon-caprolactam as reactive solvent, with caprolactam sodium as a catalyst in the presence of TPEU, with TPEU content varying from 2.5% to 10% by weight. In situ anionic ring-opening polymerization and in situ compatibilization to prepare TPEU/MCPA6 blends were carried out in one step. The TPEU chains, which underwent thermal dissociation in amine solvents to bear isocyanate groups, acted as macroactivator to initiate MCPA6 chain growth from the TPEU chains and form graft copolymers of TPEUco-MCPA6 to improve compatibility between TPEU and MCPA6. The structure and thermal properties were characterized by means of Fourier transform infrared spectroscopy, H-1-NMR spectroscopy, differential scanning calorimetry and scanning electron microscopy. (c) 2006 Society of Chemical Industry.