分子量分布对等规聚丙烯卷绕丝织构形成的影响

本文研究了分子量分布对聚丙烯卷绕丝结构和性能的影响。结果表明,聚丙烯树脂中的高分子量尾端对卷绕丝的结构有明显影响。在通常的纺丝条件下,用控制降解的聚丙烯树脂纺得的卷绕丝具有低取向的次晶结构;而在相同的粘均分子量和纺丝条件下,高分子量尾端的存在使聚丙烯易于在纺丝线上生成结晶性较高的α-晶型,卷绕丝的取向也随高分子量尾端而显著增大。高分子量尾端对卷绕丝结构的影响,导致卷绕丝牵伸性能和成品纤维力学性能变差。

EFFECT OF MOLECULAR WEIGHT DISTRIBUTION ON THETEXTURE FORMATION OF AS-SPUN ISOTATICPOLYPROPYLENE FIBER

The effects of molecular weight distribution on the texture formation of as. spun fibers and mechanical properties of polypropylene fibers have been studied. It is shown that the texture formation of as-spun fibers is very sensitive to the presence of high molecalar weight tail in the MWD of polypropylene resin. Under ordinary spinning conditions the as-spun fiber obtained from controlled degraded polypropylene resin showed smectic structure with low degree of oritation. However, in the presence of some high molecular weight tail incorproated to the degraded polypropylene resin gave as-spun fibers in a-crystalline modification, although the viscosity average molecular weight and spinning conditions were kept the same. In addition, the birefringence of the as-spun fibers increased sharphy with increasing amocnt of the high molecular weight tail in the MWP. The different texture of as-spun fibers resulted in big difference in stretching behavior of the as-spun fiber and mechanical properties of drawn fibers.