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.

摘要

普通高强 (HT) 聚对苯二甲酸乙二醇酯 (PET) 工业丝和阻燃高强 (FRHT) 涤纶工业丝在蠕变过程中的蠕变行为和微观结构演变的潜在机制分别在本文。采用同步辐射广角X射线散射（WAXS）和小角X射线散射（SAXS）、双折射测试、FTIR等方法研究和比较了两种纱线蠕变后的超分子、微纳和构象结构。结果表明，在相同蠕变条件下，FRHT的蠕变变形较大，蠕变恢复率低于HT。两种纱线的蠕变变形主要发生在非晶区，机理不同，并且它们在晶体区域的晶体取向和结晶度变化很小。HT纱线结晶度高，无定形取向，蠕变主要为可逆弹性蠕变，弹性回复率高。相比之下，由于较低的初始结晶度和无定形取向，FRHT 纱线具有更多的不可逆塑性蠕变，这在蠕变变形中起关键作用。