利用水凝胶收缩内应力制备取向BN/PVA高面外导热复合材料

BN/PVA Composite with High Through-plane Thermal Conductivity by Using Internal Stress of Hydrogel Shrinkage

介绍了一种不需要额外提供外场力而获得高面外导热的简单有效的方法。利用氮化硼(BN)/聚乙烯醇(PVA)水凝胶在丙酮中收缩的内应力,使得BN在内部发生旋转、位移,因此得到更好的面外取向,最终获得更高的面外导热系数。添加BN质量分数15%时,面外导热系数为2.78 W/(m·K),是普通冻干样品的3倍。这种利用材料自身收缩内应力而使填料获得面外取向的方法,使加工变得更加的简洁高效,在未来的导热材料制备中,有很大的运用前景。

A simple and effective method to obtain high through-plane plane thermal conductivity without external field force was introduced.Using the shrinkage of polyvinyl alcohol(PVA)hydrogels in acetone,the boron nitride(BN)was added during the preparation of hydrogels,which could be rearranged,resulting in better through-plane orientation and higher through-plane thermal conductivity coefficient.When 15%mass fraction of BN is added,the through-plane thermal conductivity is 2.78 W/(m·K),which is 3 times higher than that of ordinary freeze-drying shrinkage.In this work,the internal stress of hydrogel shrinkage is used as the driving force for the directional arrangement of fillers to obtain better orientation and thus higher thermal conductivity,which provides a new idea for obtaining directional arrangement of fillers.