熔融纺丝成形条件对PET初生丝超分子结构及其力学性能的影响——第1报 不同纺速下PET初生丝超分子结构及其力学性能的研究

本文借助于沸水收缩率、自然拉伸比以及用X射线衍射法测定的结晶度,表观晶粒尺寸和晶区取向因子等指标来描述熔融纺丝时不同纺速下PET初生丝的超分子结构。纺丝速度在1500～4800m/min范围内变化。测得的数据表明在较低的纺速下卷取的PET初生丝是不结晶的,而在较高纺速下纺制的PET初生丝结晶度要高得多。在实验的纺速范围内,PET初生丝的结晶度在纺速增加的过程中有突变现象,这主要是分子取向诱导所致,也即存在一个诱导结晶的临界取向度。最后,就不同纺速下PET初生丝的力学性能特征值进行了讨论。

EFFECT OF FORMATION CONDITION IN MELT SPINNINGON THE SUPPERMOLECULAR STRUCTURE AND THEMECHNICAL PROPERTY OF PET SPUN FILAMENT——Pt. I. STUDY ON THD SUPPERMOLECULAR STRUCTURE ANDTHE MECHNICAL PROPERTY OF PET SPUN FILAMENTAT DIFFERENT SPINNING SPEE

In this paper the suppermolecular structures of PET spun filament at different spinning speed from 1500 -4800m/min are described by means of boiling water shrinkage, natural draw ratio and the crystallinity with the crystal size measured by the method of wide angle X-ray diffraction. PET spun filaments at low spinning speed are noncrystalline but have higher crystallinity at high spinning speeds. In the range of experiment, the crystallinity of PET spun filament increases with the increasing spinning speed and appears a suddenly change which is induced by the molecular orientation,that is,there occurs a critical orientation degree of induction crystallization. The characteristics of mechanical property of PET spun filament at different spinning speed are discussed finally.