English Abstract

Effects of Annealing Temperature on the Micro-Aggregation Structure and Properties for Thermoplastic Polyurethane Elastomers Satoshi YAMASAKI Graduate School of Science and Technology R&D Center, Mitsui Takeda Chemicals, Inc., Sodegaura, Japan Daisuke NISHIGUCHI R&D Center, Mitsui Takeda Chemicals, Inc., Sodegaura, Japan Ken KOJIO Faculty of Engineering, Nagasaki University, Nagasaki, Japan Mutsuhisa FURUKAWA Graduate School of Science and Technology Nippon Gomu Kyokaishi,(2006),79(1),3-9 Original Paper in Japanese Abstract The effects of annealing temperature on the micro-aggregation structure, the mechanical and melting properties of thermoplastic polyurethane elastomer (TPU) were investigated. TPU was composed of poly{(tetramethylene adipate)-co-(hexamethylene adipate)} glycol, 4,4'-diphenylmethane diisocyanate and 1,4-butanediol units. The TPU sheets prepared by injection molding were annealed at various temperatures from 23 to 120 for 4 h. Differential scanning calorimetry, pulsed nuclear magnetic resonance and dynamic viscoelastic measurements revealed that the degree of micro-phase separation of the TPUs became stronger with increasing annealing temperature owing to the progress of the formation of well-organized hard segment domains. Dynamic storage modulus of the rubbery increasing annealing temperature, respectively. The temperature sweep experiments for molten TPUs indicated that the critical gel temperature at intersection between G' and G", increased with increasing annealing temperature. In addition, the TPUs showed the strain hardening of uniaxial elongation viscosity with increasing annealing temperature owing to residual hard segment domains at the operating temperature. It was revealed that the formation of well-organized hard segment domains by annealing strongly influences on not only mechanical properties but also melting ones of the TPUs. (Received on June 28, 2005) (Accepted on November 11, 2005) Keywords: Thermoplastic polyurethane elastomers, Annealing temperature, Micro-aggregation structure, Mechanical properties, Melting properties, Critical gel temperature, Uniaxial elongational viscosity, Strain hardening

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