双隔离结构聚乙烯/石墨烯导热复合材料的研究

Study on double-segregated polyethylene/graphene composites with high thermal conductivity

采用聚二烯丙基二甲基氯化铵改性石墨烯纳米片、聚苯乙烯磺酸钠改性聚乙烯颗粒,通过静电诱导自组装和热压成型工艺制备了具有蜂窝状石墨烯框架的聚乙烯复合材料(N-PE-HD/P-GNPs)。利用红外光谱仪、扫描电子显微镜、导热系数测试仪、电子拉力试验机对复合材料的改性状态、微观形貌、导热性能和力学性能等进行分析表征。结果表明,嵌入式连续石墨烯框架能够有效提升复合材料的导热性能,当P-GNPs含量为20%(质量分数,下同)时,N-PE-HD/PGNPs体系的热导率达到2.51 W/(m·K),相对于PE-HD/GNPs体系[1.71W/(m·K)]和纯PE-HD基体[0.44 W/(m·K)]分别提高1.47和5.70倍;同时复合材料可保持较好的力学性能和热稳定性,其拉伸强度、弹性模量、断裂伸长率分别为29.1 MPa、114 MPa、48%,而熔点和热分解温度分别为135.2℃和458℃,比纯PE-HD提高了2℃和11℃。

Polyethylene-based composites(N-PE-HD/P-GNPs)with a honeycomb graphene framework were prepared through electrostatic induction self-assembly and hot pressing process employing poly(diallyldimethylammonium chloride)-modified graphene nanosheets(P-GNPs)and polystyrene sulfonate-modified polyethylene particles(N-PE-HD)as raw materials.The morphology,microstructure,thermal conductivity,and mechanical properties of the composites were characterized using Fourier-transform infrared spectrometer,scanning electron microscopy,thermal conductivity tester,and electronic tensile testing machine.The results indicated that the formation of a continuous graphene framework effectively improved the thermal conductivity of the polyethylene-based composites.The N-PE-HD/P-GNPs system exhibited a thermal conductivity of 2.51 W/(m·K)with the addition of 20 wt%P-GNPs.This result is higher than1.71 W/(m·K)of PE-HD/GNPs system by 1.47 times and 0.44 W/(m·K)of pure PE-HD matrix by 5.70 times.The N-PE-HD/P-GN Ps composites also showed tensile strength of 29.1 MPa,Young’s modulus of 114 MPa,and elongation at break of 48%.Their melting point and thermal decomposition temperature were determined to be 135.2 and458℃,which are higher than those of pure PE-HD by 2℃and 11°C,respectively.