高密度聚乙烯/全同立构聚丙烯共混物超拉伸纤维的热行为与力学行为

Thermal and Mechanical Behavior of High Density Polyethylene/ Isotactic Polypropylene Ultradrawn Fibers

用热拉法制备了高密度聚乙烯(HDPE)/全同立构聚丙烯(iPP)共混物超拉伸纤维,研究了拉伸比对其热行为及力学行为的影响,随拉伸比增加,纤维中HDPE与iPP的结晶度增大,熔融温度升高、熔程变宽;纤维中HDPE与iPP的结晶度低于其纯组分,熔融湿度与熔程基本不受组分比的影响,随拉伸比增加,纤维的模量增高,以HDPE为主的纤维的拉伸强度增大,以iPP为主的纤维拉伸强度增至一定值后,不再随拉伸比增加而增大,并有下降趋势。

Ultradrawn fibers of high density polyethylene (HDPE)/isotactic polypropylene (iPP) blends have been prepared by hot-drawing and the influences of draw ratio and component ratio on the thermal and mechanical behavior of the ultradrawn fibers were investigated by thermal analyses and tensile tests respectively. The DSC result shows that with increasing the draw ratio, the crystallinities of HDPE and iPP, as well as their blends, and the melting temperatures are increased, whereas the melting range is reduced. The crystallinities of both HDPE and iPP are reduced in blends and the melting temperature and melting range of the two components are not affected by the component ratio. The result of tensile tests shows that the tensile modulus of ultradrawn fibers is increased with the increase of draw ratio and the tensile strength of HDPE rich-in fibers is increased with increasing the draw ratio, whereas the tensile strength of iPP rich-in fibers is decreased when the draw ratio is increased to a certain value.