【摘要】 以炭黑(CB)为导电填料,均聚聚丙烯(i PP)和抗冲聚丙烯(hi PP)为基体,通过熔融共混法制备了i PP/CB和hi PP/CB复合材料,研究了基体结晶度对复合材料渗流阈值的影响。表征了i PP/CB复合材料和hi PP/CB复合材料的熔融、结晶行为,并观测了复合材料的微观结构,结果显示CB在结晶度更高的i PP中形成了更完善的导电网络。经测试,i PP/CB复合材料的渗流阈值为CB质量分数2.69%,室温体积电阻率为9.3×104Ω·m,PTC强度为0.55;hi PP/CB复合材料的渗流阈值为CB质量分数3.81%,室温体积电阻率为8.9×105Ω·m,PTC强度为0.42。表明结晶度更高的基体i PP可以更有效地降低复合材料的渗流阈值。更多还原

【Abstract】 Polypropylene composites were prepared by mechanical melt blending method,using homo-polypropylene(i PP) and high impact polypropylene(hi PP,copolymerization with 7% PE) as the matrix and carbon black(CB) as the fillers. The influence of crystallinity on percolation threshold of composites was illustrated. The melting and crystallization behaviors of i PP/CB and hi PP/CB composites were characterized,and the microstructre of composites was observed. The result showed that CB could form more complete conductive network in i PP phase which had higher crystallinity. The percolation threshold of i PP/CB composites was 2.69% CB mass fraction. The material’s volume resistivity was 9.3×104 Ω · m and the PTC intensity of this material was 0.55. The percolation threshold of hi PP/CB polymer composites was 3.81% CB mass fraction. The volume resistivity of room temperature was 8.9×105 Ω · m and the material’s PTC intensity was 0.42. Results indicate that the degree of crystalline of matix will affect percolation threshold and electric properties.更多还原