Poly(trimethylene terephthalate-b-poly(trimethylene ether) glycol) copolymers: From bio-based thermoplastic elastomers to elastic fibers for apparel

Introducing the renewable poly(trimethylene ether glycol) (PO3G) as soft segments into bio-based poly(propylene terephthalate) (PTT), which is synthesized from the bio-based propylene glycol (PDO) monomer, results in thermoplastic polyester elastomers (PTT-PO3G) with superior thermomechanical properties. As the PO3G content in PTT-PO3G copolymers increased from 20 wt% to 60 wt%, the melting temperatures of these copolymers decreased from 220 to 174°C, and the tensile strength decreased from 31.7 to 4.2 MPa with the Shore hardness falling from 60 to 26 D, whereas the elongation at break showed an increase tendency from 697 % to 1074 %. Characterizations utilizing dynamic thermomechanical analysis (DMA), small angle X-ray scattering (SAXS), and atomic force microscopy (AFM) revealed the presence of microphase separations in PTT-PO3G copolymers. The strength and moisture regain of PTT-PO3G-20 elastic fibers fabricated via an eco-friendly melt spinning technique reach 1.42 cN/dtex and 1.52 %, which are 58 % and 407 % higher than those of traditional wet-spun Spandex® fibers, respectively. Surprisedly, the resilience of PTT-PO3G-20 fibers exceeded 96 % at an elongation of 20 %, demonstrating its promising potential as a sustainable alternative to Spandex® fibers in textile applications. The excellent thermodynamic properties indicate that the bio-based PTT-PO3G copolymers have great potential to replace traditional petroleum-based elastomers for promoting the sustainable and low-carbon global development.