Preparation and Characterization of High Molecular Weight Thermoplastic Polyetherester Elastomers Using Chain Extender

Thermoplastic polyetherester elastomer (TPEE) based on poly(butylene terephthalate) (PBT) as a hard segment and poly(tetramethylene ether glycol terephthalate) (PTMGT) as a soft segment was synthesized with hard segment content (HSC) 35 wt%. The high molecular weight TPEE copolymer was successfully prepared by using MDI as a chain extender from the TPEE synthesized. The intrinsic viscosity of the TPEE copolymer containing 3 wt% of MDI increased from 1.56 dl/g to 2.13 dl/g and the melt index decreased from 54.2 g/min to 11.5 g/min. The breaking stress of TPEE-MDI monofilament increased with MDI content and the breaking strain decreased with increasing MDI content. However, it is noticeable that the breaking stress of TPEE-MDI 3 wt% copolymer monofilament showed 41 % enhanced breaking stress while still retained pretty high breaking strain, i.e. 825 %. The elastic recovery of TPEE-MDI 1 wt% monofilament was 80.7 % in the first cycle and 76.0 % in the final cycle, which were higher than that of TPEE both in the first and the final cycles. These results meant that TPEE-MDI copolymer fiber could have enhanced elastic recovery as well as enhanced breaking stress.