Synthesis and characterizations of branched poly(butylene isophthalate)-co-poly(tetramethylene glycol)-co-poly(ethylene glycol) fibers with excellent low temperature elastic recovery

To improve the low temperature elastic recovery and tensile properties of the traditional poly(ether-ester), a series of randomly branched poly(ether-ester)s consisting of poly(butylene isophthalate) as hard segment, poly(tetramethylene glycol) and poly(ethylene glycol) as mixed soft segment, and trimethylolpropane as trifunctional monomer were synthesized. The structure and composition of the samples were characterized by 1 H NMR and FTIR-spectroscopy. The tensile strength, elongation at break and the low temperature elastic recovery were used to characterize the mechanical properties of the synthetic polymers. The results indicate that the branched poly(ether-ester) showed an increment of mechanical and thermal properties with the increasing content of branching agent in the polymer matrix. Moreover, the low temperature elastic recovery and tensile properties of branched poly(ether-ester) were superior comparing to the traditional poly(ether-ester)s.