硬 PVC 结构泡沫塑料的流变行为—口模参数对发泡行为的影响

The Rheological Behavior of Rpvc-SF——Influence of Die Parameter On Foam Behavior

本文详细论述了使用直接装在普通单螺杆挤出机上的“毛细管”机头研究硬PVC 结构泡沫塑料(RPVC-SF)挤出过程中流变行为的全过程。实验结果表明:含发泡剂 AC 的 PVC 熔融物的流变行为具有假塑性流体的特性,可以表示为 S_S=K·Sr^n,流变行为指数 n<<1,机头口模的进口角α、直径 D 和长度 L 对 RPVC-SF 的流变行为有强烈影响。使用合适参数的口模,例如α=90度,L/D=3∶1-5∶1,就能获得密度 d 小于0.8g/cm^3的制件。

The theological behavior study of the extruded rigid PVC structural foamplastics(RPVC-SF)was carried out with“capillary die”fitted on Theconventional single screw extruder.It was found that the rheological beha-vior of PVC melt contained with the blowing agent AC appears to be pseudo-plastic fluid characteristic,and can be expressed as Ss=K·S_r^n,flow behaviorindex n《l,and that the entrance angle a,diameter D and length L ofextrusion die affected strongly the rheological behavior of RPVC-SF,Theoptimal die parameters are a=90°and L:d=3:1-5:1 for achieving a lowerdensity(d<0,89/cm^3)products。