Study On Properties Of SCM Whisker Reinforced PP Composites

Whiskers have been widely used in composites for their perfect properties nowadays.In this paper, the flow fields of nine screw configurations for three-dimensional isothermal Non-Newtonian model were simulated by POLYFLOW. Screw configurations included (TME+FTX ),(FTX+ TME ),(TME+SME),(SME+TME),(FTX+SME),(SME+FTX),(KB),(TME) and (SE+FTX+SE) . Pressure profile, shear stress profile, weighted average shear stress, backflow rate and cumulate residence time distribution were obtained. It had been found that screw configuration (KB ), (TME+SME ) and(SME+TME) have both high distributive and dispersive mixing ability. There were good distributive ability in screw configuration (FTX+SME) and(SE+FTX+SE) .In this paper, composites of PP reinforced by SCM whiskers were prepared in a co-rotating intermeshing twin screw extruder. Influence of coupling agent, SCM whiskers and screw configurations on properties of SCM/PP composites were studied. Mechanical properties test showed that tensile strength and impact strength of SCM/PP composites increased until the coupling agent content reached about 2.0%, contrasting to the mass of SCM whiskers, and bending strength of SCM/PP composites was best when coupling agent reached 3.0%. The melt flow rate of composites decreased with the increasing content of coupling agent. Along with SCM whiskers content increased, tensile strength, bending strength and impact strength of composites enhanced when SCM whiskers content did not reached 20%. It could be found that mechanical properties of composites extruded by screw configuration ( SE+FTX+SE) were better than composites extruded by other screw configurations, so it was proposed to be applied in preparation of SCM/PP composites.