Oriented “shish-kebab” structures could be obtained by shearing to enhance the mechanical properties of polymer samples markedly. However, the effect of shear mode on mechanical properties is still uncertain. The study of stepped hoop shear field on the isotactic polypropylene (iPP) pipe was developed through applying a self-designed rotational shear system (RSS). The effect of stepped shear field on the microstructure and comprehensive properties of iPP pipe was investigated by the comparison with continuous shear. It could be found that the loosely-assembled shish-kebabs with the larger size were formed in the continuous shear pipes, but the smaller and tightly-stacked ones existed in the pipes with stepped shear. Surprisingly, due to differential morphologies under different shear modes, better comprehensive mechanical properties were obtained in the pipes with stepped shear.

通过剪切可以明显提高聚合物样品的机械性能，从而获得定向的“烤肉串”结构。但是，剪切模式对机械性能的影响仍然不确定。通过应用自行设计的旋转剪切系统（RSS），对等规聚丙烯（i PP）管材上的箍箍剪切场进行了研究。阶梯剪切场对的微观结构和综合性能的影响我通过与连续剪切的比较研究了PP管。可以发现，在连续剪切管中形成了较大尺寸的散装烤肉串，但在阶梯剪切管中却存在较小且紧密堆积的烤肉串。出乎意料的是，由于在不同剪切模式下的形貌不同，在阶梯式剪切的管道中获得了更好的综合机械性能。