叶片式正位移挤出机对PS／HDPE混合效果的影响

摘要

为考察叶片式正位移挤出机停留时间及转子轴转速对共混物微观结构及性能的影响，在自行研制的挤出机上进行PS/HDPE熔融共混实验，沿挤出方向进行取样并进行测试与表征，分析了转子轴转速、取样位置等对共混物力学性能及相形态的影响。实验结果表明：在相同转子轴转速条件下，距离进料口越远，复合材料的拉伸强度先快速升高，而后基本保持不变，转子轴转速较高时拉伸强度升高的速度较快；在同一取样位置，复合材料的拉伸强度随转子轴转速的升高先快速增加然后缓慢增加，存在最佳转速；扫描电镜照片显示分散相PS呈椭球形，沿挤出方向PS的粒径开始以较快的速度减小，而后减小的速度逐渐变慢。叶片式正位移挤出机中物料能在短的热机械历程内实现共混物的混合，混合效率得到提高。%The PS/HDPE melt blending experiments were conducted with a self-made positive displacement flow type vane extruder. Samples obtained at four sampling locations along extrusion direction were used to characterize by tensile test and SEM. The influences of rotating speed and sampling location on mechanical properties and morphology of the composites were studied. The experimental results showed that the longer the distance from the feed inlet the tensile strength of the blends increased. The tensile strength increased rapidly first and then remained almost unchanged. The higher of the rotating speed the tensile strength increased faster. With the increase of rotator speed, the tensile strength at the fixed sampling location increased rapidly first and then slowly. There was an optimum rotator speed. As shown in the SEM photographs the dispersed phases of PS were ellipsoidal shaped in continuous phase. The particle size decreased rapidly first along extrusion direction and then decreased slowly. Materials can be mixed homogeneously within short thermo-mechanical history in a positive displacement flow type vane extruder. The mixing efficiency can be increased with this type of extruder.