Synthesis and characteristics of thermoplastic elastomer based on polyamide-6

A new class of polyether amide thermoplastic elastomers (TPAE) was synthesized via a three-step polymerization route. In the first step a binary carboxyl terminated polyamide-6 (PA6) with relatively low number-average molecular weight was prepared via a caprolactam hydrolytic ring-opening process. 4,4'-Diphenylmethane diisocyanate (MDI) was reacted with the PA6 to produce PA6-MDI hard segments in the second step. Chain extension of the hard segments with poly(tetramethylene glycol) was the last step to furnish a series of new TPAEs. Structural characterization, physical properties and the effects of reaction conditions on the properties of the copolymer were investigated by infrared spectroscopy, (1)H nuclear magnetic resonance spectroscopy and other analytical techniques. Possible side reactions and phase separation are reported. (C) 2011 Society of Chemical Industry