Study On The Preparation And Structure-Property Of Thermoplastic Polyamide-6 Elastomer

Thermoplastic elastomer (TPE) is a multifunctional material, which has rubber elasticity at ambient temperature and can be extrusion formed at high temperature. It has elasticity of rubber, melt flow characteristics and reusability of plastics. So, it can be used in many fields such as automobiles, architectures, medical equipments and so on. Polyamide thermoplastic elastomer (TPAE) is a new type of thermoplastic elastomer which has been developed recently. The same as TPU and TPEE, Polyamide thermoplastic elastomer (TPAE) is a kind of block copolymers. Polyamide 6 thermoplastic elastomer is an important product of TPAE. It can be used as plastic and fiber material. Its properties could be adjusted by modification of chemical structure and morphology to meet different kind of requires.A new kind of polyamide 6 thermoplastic elastomer was synthesized by two steps in this article. Firstly, PA6 hard segment with two carboxyl terminal group had been synthesized. Then polyamide 6 thermoplastic elastomer was synthesized by PA6 hard segment and PTMG(Poly tetra-ethylene-glycol) soft segment. Research shows that the optimal reaction conditions of first step are time:5hours; temperature:250℃; air pressure:500-1000Pa; Optimal reaction conditions of second step are time:3hours; temperature:250℃; air pressure:500-1000Pa; catalyst: 1 %weight of PTMG. The highest relative viscosity of product is 1.74 and the lowest rate of extraction in boiling water is 3.6%.In this article, the structure and properties of polyamide elastomer synthesized were studied. IR spectra of product shows that a new ester linkage appeared and -OH group of polyether disappeared. It indicated that the product is a segmented copolymer linked by ester group. The thermal gravimetric analysis (TGA) and DSC curves of the product shows that it can be extruded and molded at 240℃～280℃which is PA6's conventional molding and processing temperature. With the increase in PTMG content, the tensile strength decreased accordingly while breaking elongation increase. But Tg, Tm and rubber plateau of copolymer didn't have evident changes according to DMA and DSC.