Preparation And Study Of The Thermoplastic Polyester Elastomer

In this study, a series of novel multiblock copolymer based on poly (butylene terephthalate)(PBT) as hard segment and poly(tetramethylene ether) glycol (PTMEG) as soft segment was successfully prepared by tetrabutyl titanate (TBT) via monomer method (first transesterification and then polycondensation) and polymeric method as catalyst with type of raw materials in the vacuum reactor.The performance of different molar ratio of1,4-butanediol (BDO):dimethyl terephthalate (DMT) as raw materials to prepare thermoplastic polyester elastomer (PBT-PTMEG) was investigated in this study. It is found that the crystallization of the polyester hard block PBT are reinforced with the increase of BDO:DMT molar ratio, the layered regulatory crystal and interface morphology are promoted by the exaltation of micro-phase separation, the crystallinity, storage modulus, tanδ as wells as the mechanical properties increased with the increase of BDO:DMT molar ratio. When BDO:DMT were more than1.6:1, residual low molecular BDO which crystallized between phase interface and PBT layered crystals greatly impeded micro-phase separation process, and the phase interface area were easily debonding or slipping, therefore, the crystallinity, storage modulus, tanδ and mechanical properties of materials reduced gradually.A further study of series of various hadrness of the PBT-PTMEG polyester elastomer was prepared by adjusting the proportion of hard segment. The results showed that the PBT-PTMEG copolymer molecular chain are consistent with the theoretical values, with the proportion of PBT content increases, material’s average degree of polymerization of the hard segment increased, the micro-phase separation increased too, and thus a corresponding increase in its melting point, glass transition temperature Tg, crystallinity WCPBT and mechanical properties, while the thermal stability of the material remains unchanged, but the intrinsic viscosity value decreased.Finally, the soft/hard segment phase structure was also discoveried in the prepration of PBT-PTMEG via polymeric method.1H-NMR and theoretical estimates showed that the hard segment average degree of polymerization increases with the addition of the PBT, the forward mechanical testing showed that PBT-PTMEG series copolymer prepared via polymeric method value the equal properties of block copolymer prepared via monomer method, but the the polymeric method seemd easier and more suitable for large-scale chemical manufacturing.