超高分子量聚乙烯冻胶纺丝-拉伸纤维结构的研究

以煤油为溶剂，汽油为萃取剂，采用冻胶纺丝 拉伸技术纺制了超高分子量聚乙烯（ＵＨＭＷ ＰＥ）纤维．利用广角Ｘ 射线衍射（ＷＡＸＤ）试验、偏光显微镜（ＰＯＭ）观察等方法研究了拉伸过程中纤维结构的变化．结果表明，在拉伸过程中，纤维大分子折叠链向伸直链转变的同时，斜方结晶的堆砌密度增大，微晶尺寸分布变窄并趋于均匀，拉伸４０倍纤维的晶胞参数为ａ＝０７３２ｎｍ，ｂ＝０４９１ｎｍ，ｃ＝０２５４ｎｍ．在拉伸４０倍左右的纤维中还能观察到因大分子结晶晶面滑移而产生的折皱带结构．在作者研究条件下，观察不到折皱带结构对纤维整体的取向态和结晶态结构的影响．

INVESTIGATION ON STRUCTURAL CHANGES OF GEL-DRAWN ULTRA-HIGH MOLECULAR WEIGHT POLYETHYLENE FIBRES

Fibres of ultra high molecular weight polyethylene(UHMW PE) were prepared with the gel fibre drawing method, in which the solvent and extraction solvent used were a general kerosene and gasoline respectively. The structural changes in the fibres during drawing process were examined by wide angle X ray diffraction(WAXD),polarising optical microscopy(POM) and density gradient column.During drawing process,folded chain structure transformed into extended chain one in the fibre,the density of fibres increased,and the dimensions of orthorhombic crystallite size trended towards a narrow distribution with the increasing draw ratio simultaneously.The orthorhombic unit cell dimensions for the fibre with a draw ratio of 40 were a =0 732nm, b =0 491nm,and c =0 254nm.In the fibre with a draw ratio of about 40,kink bands were observed.They are suggested to correspond to the local crystalline slip due to the effect of winding tension,and the smaller the winding roller diameter,the more clearly they can be observed.In present work, the effect due to the existence of kink bands on the structure of orientation and crystallinity of fibre bulk was not observed.