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设计可产生周期性收敛—发散流动的模头,使流动过程中物料受到周期性的压缩与膨胀作用,物料受到拉伸应力与剪切应力的复合应力作用,从而有利于提高混合效果;通过改变物料流经收敛板的次数可调整物料受到压缩与膨胀作用的停留时间。利用该模头在单螺杆挤出机上进行了CaCO3填充高密度聚乙烯(HDPE)熔融共混实验,并对复合材料进行宏观力学性能测试与微观结构表征,测试结果表明:收敛—发散流动能提高复合材料的力学性能,物料受到反复压缩与膨胀作用的停留时间对复合材料性能的提高有重要影响,当CaCO3含量高时需要较长时间的压缩与膨胀作用才能达到提高复合材料性能的目的;从复合材料断面的扫描电镜照片可以看出经收敛—发散流动作用后复合材料中CaCO3粒径更细,粒径分布更均匀。
Design can produce periodic convergence - divergent flow of the die, the flow process of materials subjected to periodic compression and expansion of the material by the tensile stress and shear stress of the composite stress, which will help improve the mixing effect; by changing Material flow through the convergence plate can adjust the number of materials subject to compression and expansion of the residence time. Using this die, a CaCO3-filled high density polyethylene (HDPE) melt blending test was carried out on a single screw extruder. The macroscopic mechanical properties and microstructure of the composites were characterized. The results show that the convergent-divergent flow energy The mechanical properties of composite materials, the material subject to repeated compression and expansion of the residence time has an important impact on the performance of the composite material, when the CaCO3 content is high need a longer time compression and expansion in order to achieve the purpose of improving the performance of composite materials; Scanning electron micrograph of the cross-section of the composite shows that CaCO3 particle size is smaller and the particle size distribution is more uniform after convergent-divergent flow.