相对分子质量及其分布对烯烃共聚物动态流变性能的影响

Effect of Relative Molecular Weight and Its Distribution of Olefin Copolymers on Dynamic Rheological Behavior

通过对一系列具有不同相对分子质量和相对分子质量分布的乙烯/α-烯烃(丁烯和己烯)共聚物的动态流变行为测试,研究了相对分子质量及其分布(即多分散性)对储能模量(G′)与频率(ω)、损耗模量(G″)与ω以及 G′与G″在低频区关系曲线的影响规律。结果表明,G′、G″与ω以及 G′与 G″的关系曲线的斜率不仅均低于理想的单分散体系(其中G′、G″与ω之间关系曲线的斜率分别在1.0～1.5和0.5～1.0的范围内,均低于单分散体系的2.0和1.0;而 G′与 G″之间关系曲线的斜率均在1.5附近,低于单分散体系的2.0),而且均随着相对分子质量或相对分子质量分布的增加而降低。

Through dynamic rheological determination, the effect of relative molecular weight and its distribution on the relationship between storage modulus （ G＇ ） or loss modulus （ G~） and frequency （ω） and between storage modulus and loss modulus for ethylene-α-olefin copolymers were studied. The slopes of the G′-ω, G″- ω, and G′- G″ curves were in the ranges of 1.0- 1.5, 0.5- 1.0, and 1.5, respectively, for polydispersed system. In contrast, the values for monodisperse system were 2.0, 1.0, and 2.0. In addition, those slopes decreased with increasing molecular weight and its distribution.