支化聚合物的熔体流变特性

Rheological Characteristics of Branched Polymer Melts

从支化聚合物的流变特性表征以及分子结构和温度对其流变行为的影响三个方面综述了支化聚合物的流变特性。长链支化结构明显延缓了整个高分子的松弛过程 ,这集中表现在剪切条件下的应变软化和拉伸条件下的应变硬化 ,而且 ,长链支化使得时 温等效原理不再有效 ,对温度的依赖性也表现出一定的复杂性。改进蛇行理论和耦合模型可以解释部分实验结果 ,但又都存在不足。因此 ,对于支化聚合物独特的流变行为 ,还需进一步的深入研究。

The rheological characteristics of branched polymers, as well as the effects of molecular structure and temperature on them, were reviewed in this paper. The molecular structure with long branches distinctly slows the relaxation process of macromolecules, which have been observed from their shear-softening and the elongation-hardening behaviors. Furthermore. the time-temperature superposition principle was reported invalid in this case, and the temperature dependence of rheological behaviors also displayed certain complexity. Although the modified reptation theory and the coupling model were able to explain some experimental results, the defects of them could exist. As a consequence, the rheological behaviors of branched polymers still need to be further understood by some systematic investigations.