不同管径聚乙烯管的旋转挤出

Rotation Extrusion of Polyethylene Pipes with Different Diameters

通过口模旋转挤出制备3种管径聚乙烯(PE)管,系统研究其结构与性能。结果表明,相较于传统挤出PE管内串晶平行与轴向,旋转挤出过程中聚合物熔体的流动是轴向牵引流动和环向拖曳流动的叠加,其方向偏离轴向,可诱导串晶偏离轴向排列,从而提高PE管的环向取向度,实现PE管的环向增强,抑制裂纹在PE管内沿轴向扩展。随PE管管径的增加,在相同旋转角速度下环向流动线速度增大,串晶偏离轴向的夹角增加,环向取向度更高,因而旋转挤出制备的大口径PE管具有更优的性能。

In this paper,polyethylene(PE)pipes with three diameters were prepared via die rotation extrusion and a thorough research was done on their microstructures and properties.The experimental results showed that compared to shish-kebab parallel to axial direction of PE pipe prepared by convention extrusion,hoop drag flow caused by die rotation was superimposed on axial traction flow during die rotation extrusion and the polymer flow direction was off the axial direction of the pipe so that the direction of shish-kebab alignment deviated from the axial direction to increase hoop orientation of the PE pipe and improve significantly the hoop strength and suppress the crack growth along the axial direction.With the increasing diameter of the PE pipe,hoop linear velocity went up at the same angular velocity and the angles of shish kebab deviated from the axial direction became larger so more improvement was achieved in the PE pipe with the longer diameter.