Melt-spun poly(ethylene terephthalate-co-1,4-cyclohexanedimethylene terephthalate) (PETG) copolyester fibers: Synergistic effect of chemical and crystal structure regulation

Abstract

In this work, a series of 1,4-cyclohexanedimethanol (CHDM)-based copolyester fibers are prepared by chemical structure design and crystal structure regulation. The chemical structures of poly(ethylene terephthalate-co-1,4-cyclohexanedimethylene terephthalate, (PETG)) copolyesters are first confirmed by 1H- and 13C-nuclear magnetic resonance which indicates that all copolyesters are random copolyesters. Then, the crystallization and melting behavior, thermal stability, and mechanical properties of copolyesters are significantly affected by the CHDM content and CHDM cis-trans isomerism ratio, showing that trans-CHDM can effectively improve the comprehensive performance of PETG copolyesters. Besides, the influence of the CHDM monomer (amount and cis-trans isomerism ratio) and melt-spinning drawing process on the crystal structure and mechanical properties (tensile strength, elongation) is also investigated by wide-angle X-ray diffraction, small-angle X-ray scattering, and tensile testing. Especially, the resultant PETG30-trans80 copolyester fibers exhibit good mechanical properties, and the tensile strength and elongation are 113.9 MPa and 136.5%, respectively. Therefore, our work provides a promising strategy for the fabrication of copolyester fiber. Highlights: Bio-based PETG copolyester was obtained. Synergistic effects of a chemical structure and drawing process of PETG fiber were discussed. The influence of drawing process on crystallization, and orientation of fiber properties was studied.