兼具导热和自修复功能的聚合物复合材料

针对聚合物复合材料存在的结构受损导致导热和力学强度降低的问题,提出利用导热填料增强自修复聚合物,实现导热性能和力学强度的快速修复.通过对双(3-氨丙基)封端的聚二甲基硅氧烷(H2N-PDMS-NH2)进行端基改性,得到脲基嘧啶酮(UPy)双封端的聚二甲基硅氧烷(UPy-PDMS-UPy),于60℃下20 h后拉伸强度修复效率可达86.6%.进一步填充羟基化氮化硼(mBN)制备兼具自修复功能的导热复合材料,研究发现mBN的填充导致复合材料强度提高但韧性降低,对导热性能和自修复功能分别起积极和不利影响.当mBN含量为30 wt%时,热导率高达2.579 W·m^?1·K^?1,于60℃下40 h后拉伸强度修复效率达82.0%.红外热像仪显示,损伤处接触10 h后,mBN-30/UPy-PDMS-UPy上表面温度接近初始温度,展现出导热通路的修复特征,实现导热与自修复功能的兼备.

Polymer Composite Material with both Thermal Conduction and Self-healing Functions

In order to obtain polymer composites with rapid self-healing function of thermal conductivity and mechanical strength degradation,a self-healing polymer reinforced by thermally conductive fillers was proposed.In this work,the bis(3-aminopropyl)terminated polydimethylsiloxane(H2N-PDMS-NH2)was modified by introducing 6-methyl-4-pyrimidinone(UPy)as end groups,which was based on the reversible cleavage and reconfigurability of the quadruple hydrogen bonds between the UPy groups.The results of Fourier infrared spectroscopy(FTIR),mechanical tensile tests and scanning electron microscopy(SEM)showed that the UPy double-terminated polydimethylsiloxane(UPy-PDMS-UPy)had good self-healing properties,and the healing efficiency of mechanical strength reached 86.6%after healing at 60℃ for 20 h.Subsequently,thermally conductive composite material with self-healing function was prepared by filling hydroxylated boron nitride(mBN)into the UPy-PDMS-UPy.It was found that mBN could enhance the tensile strength of the composite material but reduce the toughness,and had positive and negative effects on thermal conductivity and self-selfing function,respectively.When the mBN content was 30 wt%,the tensile strength healing efficiency reached 82.0%after 40 h at 60℃.And the thermal conductivity reached as high as 2.579 W·m^?1·K^?1 but fell with further increase of mBN content due to the aggregations and holes.Therefore,mBN-30/UPy-PDMS-UPy was involved in the following measurements.Infrared thermal imaging camera showed that the upper surface temperature of mBN-30/UPy-PDMS-UPy was close to the initial temperature after healing for 10 h,which showed good self-healing function of heat transfer,and the relevant self-healing machnism was discussed in the end.The design achieved the self-healing function of both mechanical strength and thermal conductivity for composite material,which provided a great guide for the design of self-healing thermal interface materials.