卷绕速度对PTT初生纤维结构与性能的影响

PTT特性粘数0.935 dL/g,卷绕速度2 500-4 000m/min,熔融纺丝制备PTT初生纤维(PTT/POY),研究了卷绕速度对其结构和性能的影响。结果表明:提高卷绕速度,PTT/POY的玻璃化温度、结晶度和密度提高,冷结晶温度和过热度降低;晶面距和晶粒尺寸略有增加,双折射先逐渐增加,达到最大值后降低,声速取向因子则逐渐增加,但非晶区取向大分子链的取向度随之减小。随卷绕速度的提高,PTT/POY的断裂强度和初始模量增加,而断裂伸长率和断裂比功降低。热拉伸倍数与卷绕速度有关,2 500~4 000 m/min时,应取1.18~1.57。

Effect of take-up velocity on structure and properties of as-spun PTT fiber

The as-spun PTT fiber ( PTT/POY) was prepared via melt spinning from PTT with intrinsic viscosity of 0. 935 dL/g at a take-up velocity in the range of 2 500 - 4 000 m/min. The effect of take-up velocity on the structure and properties of as-spun PTT fiber was studied. The results showed that the increase of take-up velocity can increase glass transition temperature, crystallinity and density, decrease cool crystallization temperature and degree of undercooling of PTT/POY, and slightly increase interplanar spacing and crystal size. The birefringence of PTT/POY was increased gradually until the maximum and then decreased and the sonic orientation factor was increased gradually with the increase of take-up velocity while the orientation of mac-romolecular chains was decreased in amorphous region. The breaking strength and initial modulus of the PTT/POY were increased with the take-up velocity while the elongation at break and the specific work to rapture were decreased. The thermal stretching ratio bearing upon take-up velocity should be in the range of 1. 18 - 1.57 at 2 500 - 4 000 m/min.