隔离结构碳纳米管/聚丙烯电磁屏蔽复合材料

Segregated Carbon Nanotube/Polypropylene Composite for Efficient Electromagnetic Interference Shielding

将碳纳米管(CNT)作为导电填料,等规聚丙烯(i PP)为基体、共聚聚丙烯(co-PP)为流动促进剂,采用注射成型的方法制备了具有隔离结构的CNT/PP复合材料,并对复合材料微观结构、电性能、电磁屏蔽性能及力学性能进行了研究。扫描电子显微镜分析结果表明,复合材料内部形成了典型的隔离结构导电网络,其中,CNT择优分布于coPP中,形成了CNT/co-PP连续相,将隔离分布的i PP微区连接起来。隔离结构导电网络的形成,使复合材料在当CNT质量含量仅为5.0%时,电导率达到了75.5 S/m,电磁屏蔽效能达到了44.3 d B。力学性能测试结果表明,当CNT含量为5.0%时,CNT/PP复合材料拉伸强度达到30 MPa,克服了传统隔离结构的复合材料力学性能较差的问题。

A segregated carbon nanotube( CNT)/polypropylene( PP) composite with efficient electromagnetic interference shielding effectiveness( EMI SE) was achieved via injection molding. CNTs were chosen as conductive filler,i PP was chosen as matrix and maintained semi-solid-state during injection,and copolymerization PP( co-PP) was chosen as flow accelerator. CNTs were pre-coated on i PP granules and 40 % co-PP guaranteed the successful injection. During the injection molding process,CNTs migrated into the co-PP continuous phase to form a segregated conductive network. The resultant CNT/PP composite with only 5. 0% CNT exhibited excellent EMI SE of 44. 3 d B,much higher than that for CNT randomly distributed one. More important,the CNT/PP composite showed excellent tensile strength of 30 MPa at 5. 0% CNT loading,indicating that the major obstacles of segregated CPCs,e. g.,the weak mechanical properties,were overcome.