PP／EVAC在拉伸流场中的相形态演变

摘要

将质量比为70/30的PP/EVAC进行共混，用单螺杆挤出机经收敛形口模挤出，考察了共混物在挤出方向和不同口模位置处的相形态。结果表明，经过螺杆剪切作用后，分散相呈片层状与纤维状结构。该分散相在口模中流动受拉伸流场作用，片层状分散相演变成截面似“哑铃形”的片层状结构，其较薄部分持续变薄甚至破裂，形成尺寸较小的片层状结构；同时纤维状分散相被拉伸变长，直径减小。%Blends of PP and EVAC (mass ratio:70∶30) were prepared by single screw extrusion mixing. The blends sustained the stretching effect in convergent die.The morphology of dispersed phases were gained and researched.The results show that after sustained the shearing action,the dispersed phases are lamellar and fibrous structures.Under the elongation flow field,the lamellar structures are stretched to ones with the dumbbell-like sections vertical to extrusion direction. The thinner part of lamel is attenuated continuously until broken into smaller ones. Meanwhile the fibres are stretched and diameter decrease.