聚合物共混物脆韧转变性能研究 Ⅳ橡胶粒子的分布对PVC/NBR共混物脆韧转变的影响

根据作者已建立的准网络形态模型和推导出的基体层厚度计算公式，从实验上研究了橡胶粒子的分布对聚氯乙烯（ＰＶＣ）／丁氰橡胶（ＮＢＲ）共混物脆韧转变的影响．结果表明，不仅无规形态ＰＶＣ／ＮＢＲ共混物存在脆韧转变主曲线，而且准网络形态ＰＶＣ／ＮＢＲ共混物也存在脆韧转变主曲线．但是两条主曲线明显不重合，表明橡胶粒子的分布对ＰＶＣ／ＮＢＲ共混物脆韧转变有显著影响．而且准网络形态ＰＶＣ／ＮＢＲ共混物的临界基体层厚度比无规形态ＰＶＣ／ＮＢＲ共混物的临界基体层厚度大得多，表明准网络形态比无规形态明显有利于增韧．因此临界基体层厚度不仅是基体的特征参数，还是界面粘结和橡胶粒子分布的函数．

STUDY OF THE BRITTLE DUCTILE TRANSTION OF POLYMER BLENDS Ⅳ THE EFFECT OF RUBBER PARTICLE DISPERSION ON THE BRITTLE DUCTILE TRANSITION OF PVC/NBR BLENDS

An experimental study of the effect of rubber particle dispersion on the brittle ductile transition of polyvinyl chlorde (PVC)/nitrible rubber (NBR) blends is carried out based on the model of pseudonetwork morphology established in our previous paper.However,two well separated master curves of brittle ductile transition for blends with the morphology of well dispersed rubber particles and with the pseudonetwork morphology were obtained,indicating that the rubber particle dispersion has a great influence on the brittle ductile transition of PVC/NBR blends.The critical matrix ligament thickness for the blends with the morphology of well dispersed rubber particles is much smaller than that for the blends with the pseudonetwork morphologyy.Therefore,the pseudonetwork morphology is much more efficient in the rubber toughening of PVC than that of well dispersed rubber particles.The present study strongly supports that the critical matrix ligament thickness is not only a material property of polymer maxtrix,but it is also a function of interfacial adhesion and rubber particle configuration.