Kanhere Sagar V, Güzdemir Özgün, Ogale Amod A
Center for Advanced Engineering Films and Fibers (CAEFF), Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, SC 29634, USA.
Polymers (Basel). 2023 Nov 15;15(22):4411. doi: 10.3390/polym15224411.
Metals are being replaced with high-performance and lightweight polymers, but their low thermal conductivity and poor electrostatic dissipative properties are significant problems. For the protection of sensitive electronic circuitry in automotive and aerospace parts, some device housing materials must provide electrostatic discharge and dissipate heat generated at higher rates as electronic circuits are increasingly miniaturized. Micro-texturing on the film surface can greatly enhance the heat dissipation area and was investigated in this study using low-cost graphite nanoplatelet (GNP)-filled LLDPE films. Micro-finned films (30 vol% GNP) having a 51 ± 10% larger heat-dissipation area were successfully produced using a continuous extrusion process. The through-thickness thermal conductivity of 30 vol% GNP-filled LLDPE was measured at 1.3 W/m·K, which represents a 200% improvement over that of pure LLDPE. For a GNP content of 30 vol%, the surface and volume electrical conductivity of the composite films also increased by 8 orders of magnitude (resistivity down from ≈10 to 10 Ω·cm) and electrostatic decay time reduced to a below-resolution limit of 0.01 s, at par with military standard requirements. Thus, micro-fin textured GNP-LLDPE offers a unique combination of electrical and thermal transport desired for the protection of electronic encapsulation materials.
金属正被高性能且轻质的聚合物所取代，但其低导热性和较差的静电耗散性能却是重大问题。对于汽车和航空航天部件中敏感电子电路的保护，随着电子电路日益小型化，一些器件外壳材料必须具备静电放电能力，并能以更高的速率散发热量。薄膜表面的微纹理化可极大地增加散热面积，本研究使用低成本的石墨纳米片（GNP）填充线性低密度聚乙烯（LLDPE）薄膜对此进行了研究。通过连续挤出工艺成功制备出了微翅片薄膜（含30体积%的GNP），其散热面积增大了51±10%。含30体积%GNP的LLDPE的厚度方向热导率经测量为1.3W/m·K，相较于纯LLDPE提高了200%。对于30体积%的GNP含量，复合薄膜的表面和体积电导率也提高了8个数量级（电阻率从≈10降至10Ω·cm），静电衰减时间缩短至低于0.01s的分辨率极限，达到了军事标准要求。因此，微翅片纹理化的GNP-LLDPE为电子封装材料的保护提供了所需的独特的电传输和热传输组合。
