MAPP对麦秸纤维-聚丙烯复合材料热力学性能的影响

Effects of MAPP on the dynamic mechanical and thermal properties of wheat straw fiber-polypropylene composites

以麦秸纤维为增强材料、聚丙烯为基体物质、马来酸酐接枝聚丙烯(MAPP)为改性剂,制备麦秸纤维-聚丙烯复合材料。利用DMA、DSC、TG和SEM,探讨了MAPP的添加量(质量百分比1%、2%、5%、10%)和麦秸纤维形态(<9、9～28、28～35、>35目)对麦秸纤维-聚丙烯复合材料的热力学性能和结晶性能的影响。结果表明:①当MAPP的添加量为2%时,麦秸纤维-聚丙烯复合材料的储能弹性模量减小;当MAPP的添加量增加到5%、10%时,复合材料的储能弹性模量增加。②在麦秸纤维-聚丙烯体系内添加MAPP后,麦秸纤维-聚丙烯复合材料的结晶温度提高约1℃,结晶度增加了4%～8%;麦秸纤维以28～35目的形态作为聚丙烯基体的增强材料时,其复合材料的结晶温度为122.7℃,结晶率达到45.8%。③麦秸纤维-聚丙烯复合材料的热分解峰温分别为355和460℃。④麦秸纤维以纤维束的形态分布在基体聚丙烯中起增强作用,在整个体系内,麦秸纤维局部团聚且断裂明显。添加MAPP后,有利于基体物质在麦秸纤维表面的均匀覆盖。

Composites of polypropylene （PP） and wheat straw fiber （9,28,35 mesh） modified by maleic anhydride polypropylene （MAPP,1%,2%,5%,10%,weight percentage） were prepared,and the dynamic flexural mechanical,thermal properties and surface morphology of wheat straw fiber-PP composites were investigated by dynamic mechanical analysis （DMA）,differential scanning calorimeters （DSC）,thermal gravimetric analysis （TGA） and scanning electron microscopy （SEM）. With incorporation of 2% MAPP,wheat straw fiber-PP composites showed the lowest storage flexural modulus （E＇）,while the composites containing 5% and 10% of MAPP exhibited the highest E＇. The DSC study revealed that the addition of the MAPP to the composites increased the nucleating ability of PP in the surface of wheat straw fiber,with an increase of 1℃ in crystallization temperature （Tc） and an increase of 4%-8% in crystallinity （Xc）. The PP composites reinforced with wheat straw fiber between 28 and 35 mesh had the highest Tc of 122.7℃ and Xc of 45.8%. The composites underwent two decomposition peaks：one peak at about 355℃ and the other shoulder at around 460℃. With the addition of MAPP,better dispersion of PP matrix in the surface of wheat straw fiber could be created.