Effects of Injection Molding Process on Mechanical Properties of Glass Fiber Reinforced PBT/Microsphere Foam Materials
Gao Liang, Zhang Chao, Zhu Naxin, Zhang Hengdi
Crerax Science and Technology Co. Ltd., Shanghai 201315, China
摘要：利用可膨胀微球注塑发泡方法制备了玻纤增强PBT/微球发泡材料，考察了不同注塑工艺对玻纤增强PBT/微球发泡材料力学性能的影响。结果表明，料筒温度、注塑压力与保压时间的提高有利于微球发泡从而降低玻纤增强PBT/微球发泡材料的密度，但料筒温度升高会使拉伸比强度值与弯曲比强度值呈先升高再下降的趋势；注塑压力增加会使拉伸比强度值先下降再上升，弯曲比强度值波动上升；保压时间增加会使拉伸比强度值与弯曲比强度值均呈上升趋势。增加背压会使玻纤增强PBT/微球发泡材料密度上升，拉伸比强度值在背压为0时最大，呈波动下降趋势，弯曲比强度值则先下降再上升。螺杆转速增加会导致玻纤增强PBT/微球发泡材料的密度先减小后增大，比强度值先增大后减小。玻纤增强PBT/微球发泡材料成型最佳工艺参数为料筒温度240℃，注塑压力1.0 MPa，背压0 MPa，保压时间5 s，螺杆转速25 r/min，发泡材料的密度为1.3472 g/cm3，减重10.78%，拉伸比强度提高6.14%，弯曲比强度增加9.74%。
Abstract：The glass fiber reinforced polybutylene terephthalate (PBT) micro-foaming material was prepared by the expansion microsphere injection foaming method. The effects of different injection molding processes on the mechanical properties of PBT/microsphere foaming materials were investigated. The results show that the increase in barrel temperature, injection pressure and dwell time is conductive to microsphere foaming, which reduces the density of glass fiber reinforced PBT/microsphere foamed materials. However, increasing barrel temperature will increase the tensile strength and the bending strength first, then decrease; increasing the injection pressure will decrease the tensile strength first and then increase, and the bending strength will increase; increasing the dwell time will increase the tensile strength and bending strength. Increasing the back pressure will increase the density of glass fiber reinforced PBT/microsphere foamed materials, and the tensile strength is maximum when the back pressure is 0, showing a downward trend in fluctuation, and the bending strength will first decrease and then increase. The increase of the screw speed causes the density of PBT/microsphere to decrease first and then increase, and the specific strength value increases first and then decreases. Therefore, the optimum process parameters for glass fiber reinforced PBT/microsphere foaming material is that barrel temperature is 240℃, injection pressure is 1.0 MPa, back pressure is 0 MPa, holding time is 5 s and screw speed is 25 r/min. The density of the foamed material is 1.3472 g/cm3, the weight loss is 10.78%, the tensile strength is increased by 6.14%, and the bending strength is increased by 9.74%.
Keywords：polybutylene terephthalate; expandable microspheres; injection molding process; mechanical property
Gao Liang，Zhang Chao，Zhu Naxin，et al. Effects of injection molding process on mechanical properties of glass fiber reinforced PBT/microsphere foam materials[J]. Engineering Plastics Application，2020，48(2)：60-65.