Effect of flame retardant on the microfine structures and creep behavior of polyester industrial yarns

Abstract

The respective underlying mechanisms of the creep behavior and microstructure evolution in the creep process of an ordinary high-tenacity (HT) poly(ethylene terephthalate) (PET) industrial yarn and a flame retardant high-tenacity (FRHT) polyester industrial yarn are identified in this article. Synchrotron radiation wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS), birefringence test, FTIR were employed to investigate and compare the supramolecular, micro–nano and conformation structures of the two yarns after creep. The results showed that, under the same creep condition, the creep deformation of FRHT was larger and the creep recovery was lower than those of HT. The creep deformation of the two yarns mainly took place in amorphous region with different mechanisms, and their changes in the crystal region in terms of crystal orientation and crystallinity were slightly. HT yarns had high crystallinity and amorphous orientation, and the creep was mainly reversible elastic creep with a high-elastic recovery rate. By contrast, there was more irreversible plastic creep for FRHT yarns due to the lower initial crystallinity and amorphous orientation, which play a key role in the creep deformation.