挤出循环对聚丙烯/竹粉复合材料力学及发泡性能的影响

通过双螺杆挤出机对30％(质量分数,下同)竹粉增强聚丙烯(PP/BP)复合材料进行循环加工,研究了挤出循环次数对PP/BP复合材料流变性能、力学性能和发泡性能的影响.结果表明,随着挤出循环次数的增加,PP/BP复合材料的表观黏度(η)先升高后降低,力学性能先增强后减弱,经第6次挤出循环后,其η、弹性模量和弯曲模量比1次...

Effects of multiple extrusions on mechanical and foaming properties of polypropylene/bamboo fiber composites

The polypropylene(PP)-based composite reinforced with 30 wt%bamboo powders(BP)was prepared through six-cycle extrusion using a twin-screw extruder.The effect of recycle times on the rheological,mechanical,and foaming properties of the BP/PP composite was investigated.The results indicated that with an increase in the cycle number of extrusion,the apparent viscosity of the composite increased at first and then tended to decrease,but its mechanical pro-perties showed an opposite trend.The apparent viscosity decreased by 23.75%after extrusion for six time.Compared to the original composite,the composite extruded six times showed a decrease in tensile strength by 17.08%and in strength by 31.18%.With an increase in the cycle number of extrusion,the composite showed a change in cell distribution from uneven to uniform,and its cell size became uniform gradually.Moreover,the distribution of BP tended to be uniform in the cell wall,and BP became short rods and granules instead of long fibers.