UHMWPE纤维的熔融行为和结晶结构的研究

用DSC法研究了超高相对分子质量聚乙烯(UHMWPE)纤维的熔融行为。随着拉伸倍数提高,纤维经松弛状态下热处理后,其熔融峰数目由1个变为2个;而经部分张力和张力状态下热处理后,其熔融峰数目均由1个变为3个。熔融峰出现的位置可分为4个区:131-138℃,141-143℃,150-152℃,155- 157℃。松弛与张力状态下热处理纤维的主熔融峰不同,前者主要是正交晶系的熔融,后者则分别对应于正交晶相向六方晶相的转变和六方晶相的熔融。经热处理的UHMWPE纤维的DSC图谱表明,代表正交晶相向六方晶相转化的熔融峰面积均有所增大,同时纤维的拉伸强度均有提高,提高幅度达31.1%。

Study on melting behavior and crystalline structure of UHMWPE fiber

The melting behavior of ultrahigh relative molecular weight polyethylene (UHMWPE) fiber was studied by DSC. The number of melting peaks was increased from 1 to 2 with the increase of draw ratio after heat treatment under relaxation and from 1 to 3 after heat treatment under partial tension or full tension. The melting peaks were observed in the range of 131 -138℃, 141 - 143℃, 150 - 152℃ and 155 - 157℃, respectively. The major melting peaks occurred at different positions under relaxation or tension. The former belonged to the melting behavior of orthorhombic system. The later corresponded to the transition from orthorhombic phase to hexagonal phase and the melting behavior of hexagonal phase separately. The DSC spectra for heat treated UHMWPE fibers showed that the area of melting peaks demonstrating the transition from orthorhombic phase to hexagonal phase was increased in some degree, and the tensile strength of the fibers was increased by 31. 1%.