相对分子质量及其分布对纤维级聚丙烯的力学性能和加工行为的影响

借助凝胶渗透色谱仪、熔体流动速率仪、电子拉力机、热重分析仪和示差扫描量热仪,研究了5种纤维级聚丙烯的相对分子质量及其分布对熔体流动指数、力学性能、热稳定性和结晶行为的影响。结果表明,随着重均相对分子质量增大,试样拉伸强度降低,断裂伸长率增大。当加工温度为200～300℃时,重均相对分子质量越低,相对分子质量分布越宽,试样热稳定性越差。在剪切速率为2 400 s^-1时,随加工温度的升高,试样表观黏度呈下降趋势。在相同条件下,经过纺丝机1辊和2辊拉伸,低重均相对分子质量的线密度和断裂伸长率小于高重均相对分子质量者。

Effect of relative molecular mass and its distribution on mechanical properties and processing behavior of fiber-grade polypropylene

The effects of relative molecular mass and its distribution on the melt flow rate,mechanical properties,thermal stability and crystallization behavior of five kinds of fiber-grade polypropylene were studied by gel permeation chromatograph,melt flow indexer,electronic tensile machine,thermal gravity analyzer and differential scanning calorimeter.The results showed that the tensile strength of samples decreased and elongation at break increased with increasing weight average relative molecular mass.The therma...