The Preparation Of Modified Copolyetheresters And The Study On Their Properties

Polyetherester elastomer has been widely used in many fields in recent years. The industrialized polyetheresters are mostly made up of poly(tetramethylene oxide)glycol (PTMG) as the soft block and poly(butylene terephthalete)(PBT) as the hard block. They have outstanding integrated properties such as high strength, good elasticity, good heat resistance and good chemistry resistance.In this paper, two types of modified PBT-PTMG were prepared by DMT route in the presence of Ti(OBu)₄ as the catalyst.1. A series of hydrophilic copolyetherester block copolymer consisting of PTMG and PEG as soft segment components and PBT as hard segment were synthesized. ¹H NMR, FTIR, PLM, XRD, water contact angle, water absorption and mechanical test were used to characterize their structure and propertities. The results showed that the products have the structure forecasted; the block ratio measured were in accordance with the feed ratio; the crystalline morphology was typical spherical crystals as determined by PLM and XRD; the water absorption and hydrophilicity of the copolyetherester increased with the increasing extent of PEG; the comprehensive mechanical properties were excellent.2. A series of poly(butylene terephthalate-co-1,4-cyclohexane dimethylene terephthelate)-b-PTMG containing different amounts of 1,4-cyclohexyldimethanol (CHDM) were synthesized. ¹H NMR, DSC, TGA and mechanical test were used to characterize their structure and propertities. The results showed that the products have the structure forecasted, but the actual content of PCT in the resulted copolyetherester was higher than the feed ratio; the melt temperature decreased with the introduction of CHDM unit in the macromolecular mainchain; they exhibit excellent thermal stability with the initial deposition temperature near 400℃; the mechanical test showed that tension strength were decreased while the elongation at break were increased dramatically.