工业用PET及PA纤维模量-应变曲线的分析

通过拉伸试验数据得到应力—应变曲线和模量-应变曲线可以更全面地反映纤维的力学性能。PET及PA的模量—应变曲线都是明显的双峰曲线。结合拉伸过程中PET纤维内部结构的变化解释PET纤维的特征模量—应变曲线，并讨论如何提高持续使用应变范围的模量问题。PET模量—应变曲线上的第一个模量峰为初始模量，标志着无定形区缠结网的破坏；无定形区蜷曲大分子伸直时模量较低，导致出现模量低谷；由于伸直的缚结大分子模量较高，出现了第二个模量峰。

Analysis of Modulus-strain Curves of PET and PA Industrial Yarns

The modulus-strain curve educed by the treatment of tensile test data is more suitable for examining the mechanical properties of yarns than the stress-strain curve itself. The modulus-strain curves of PET and PA have two peaks. This paper analyses the typical modulus-strain curves of PET yarns through the physical structure changes of this fiber during stretching test, and discusses how to enhance the modulus of sustaining use strain regions. The first maximum of modulus-strain curve of PET is due to the disintegration of the entanglement network. The valley after the first peak can be attributed to low modulus of the uncoiling molecular chains in the amorphous regions. Owing to the high modulus of taut-tie molecules, the second modulus peak appears.