导热高分子聚合物研究进展

Research progress of polymers with high thermal conductivity

传统高分子聚合物是良好的电绝缘体和热绝缘体.高分子聚合物具备质量轻、耐腐蚀、可加工、可穿戴、电绝缘、低成本等优异特性.高分子聚合物被广泛应用于各种器件.由于高分子材料的热导率比较低(0.1—0.5 W·m^(-1)·K^(-1)),热管理(散热)面临严峻的挑战.理论及实验工作表明,先进高分子材料可以具有比传统传热材料(金属和陶瓷)更高热导率.Fermi-Pasta-Ulam(FPU)理论结果发现低维度原子链具有非常高的热导率.广泛使用的聚乙烯热绝缘体可以被转变为热导体:拉伸聚乙烯纳米纤维的热导率大约为104 W·m^(-1)·K^(-1),拉伸的聚乙烯薄膜热导率大约为62 W·m^(-1)·K^(-1).首先,本文通过理论和实验结果总结导热高分子材料的传热机理研究进展,并讨论了导热高分子聚合物的制备策略;然后,讨论了在传热机制及宏量制备方面,高分子聚合物研究领域所面临的新挑战;最后,对导热高分子的热管理应用前景进行了展望.例如,导热高分子聚合物在耐腐蚀散热片、低成本太阳能热水收集器、可穿戴智能冷却服饰、电子绝缘却高导热的电子封装材料等领域具有不可替代的热管理应用前景.

Developing thermally conductive polymers is of fundamental interest and technological importance.Common polymers have low thermal conductivities on the order of 0.1 W·m^(-1)·K^(-1)and thus are regarded as thermal insulators.Compared with the traditional heat conductors(metals and ceramics),polymers have unparalleled combined properties such as light weight,corrosion resistance,electrical insulation and low cost.Turning polymer insulators into heat conductors will provide new opportunities for future thermal management applications.Polymers may replace many metals and ceramics,serving as lightweight heat dissipators in electronics,refrigerators,and electrical vehicles.In this review and perspectives,we discuss the research progress of thermal transport mechanisms in polymers and reveal the relations between thermal conductivity and polymer structural parameters such as bond strength,crystallinity,crystallite size,chain orientation,radius of gyration,and molecular weight.We discuss the advanced strategies for developing thermally conductive polymers by both bottom-up and top-down approaches.We highlight how thermally conductive polymers provide new opportunities for thermal management applications.Finally,we emphasize the future challenges to and opportunities for designing and synthesizing polymers with metal-like thermal conductivity and exploring the thermal transport physics in polymers.We believe that the thermally conductive polymers with their unparalleled combination of characteristics(light weight,electrical insulation,easy processability,corrosion resistance,etc.)promise to possess many existing and unforeseen thermal management applications.