Correlation of rheology–orientation–tensile property in isotactic polypropylene/organoclay nanocomposites
Correlation of rheology–orientation–tensile property in isotactic polypropylene/organoclay nanocomposites
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DOI：
10.1016/j.actamat.2007.01.020
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发表时间：
2007-05
期刊：
影响因子：
9.4
通讯作者：
Ke Wang;Si Liang;Ping Zhao;C. Qu;Hong Tan;R. Du;Qin Zhang;Q. Fu
中科院分区：
文献类型：
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作者：
Ke Wang;Si Liang;Ping Zhao;C. Qu;Hong Tan;R. Du;Qin Zhang;Q. Fu
三种等规聚丙烯（iPP）/有机粘土纳米复合材料，其改变了基础树脂的极性和分子量，但固定了粘土含量（10 wt.%）通过熔融共混制备。为了将流变性能与注塑棒的取向行为和拉伸性能联系起来，分别通过大振幅振荡剪切测量和应力松弛实验研究了这些熔融复合材料的剪切响应和失取向动力学。然后，进行动态保压注射成型，在凝固阶段对熔融复合材料施加振荡剪切，以制备具有高度取向的复合材料。通过二维广角X射线散射分析，观察了注塑棒的取向结构。研究结果首次表明，大幅度剪切和应力松弛诱导的取向等流变行为，将为实际注塑成型工艺中评价纳米复合材料取向能力提供可靠的参考依据。流变学对剪切的响应和失取向动力学在决定模塑复合材料的取向和拉伸强度方面起着至关重要的作用。
Three isotactic polypropylene(iPP)/organoclay nanocomposites with changed basal resin polarity and molecular weight but fixed clay content (10wt.%) were prepared through melt-blending. To correlate the rheological properties with the orientation behavior and tensile property in injection-molded bars, the shear response and disorientation kinetics of those molten composites were investigated through large-amplitude oscillatory shear measurements and stress relaxation experiments, respectively. Then, dynamic packing injection molding was carried out to exert oscillatory shear on the molten composites during the solidification stage, for preparation of composites with high-level orientation. The orientated structures of injection-molded bars were inspected through 2-D wide-angle X-ray scattering analysis. Our results indicated for the first time that the rheological behaviors, such as alignment induced by large-amplitude shear and stress relaxation, would be the reliable references for estimating the orientation capability of nanocomposites in practical injection-molded processing. The rheological response to shear and the disorientation kinetics play crucial roles in determining the orientation and tensile strength of molded composites.