Liquid crystal functionalized boron nitride fillers/liquid crystal epoxy thermally conductive composites

The thermal conductivity coefficient (λ)of thermally conductive polymer composites is difficult to reach the expected value due to the intrinsic low λ value of polymer matrix. Meanwhile, the interfacial thermal resistance between thermally conductive fillers and polymer matrix is also another important factor leading to the poor thermal conductivity. In this work, liquid crystal epoxy molecules are in - situ grafted on globular boron nitride (LCE-g- (GBN-100), gGBN-100)fillers, which are melt-blended with main-chain liquid crystal epoxy resin (M-LCER)to fabricate the gGBN-100/M-LCER thermally conductive composites. Results show that the introduction of LCE on the surface of GBN-100 endows the liquid crystal properties of gGBN-100 fillers, and effectively reduces the interfacial thermal resistance between gGBN-100 fillers and M-LCER matrix. When the mass fraction of gGBN-100 fillers is 30%, the λ of gGBN-100/M-LCER thermally conductive composites is 1. 12 W/mK, which is 2. 2 times of that of pure M-LCER matrix (λ of 0. 51 W/mK) and also higher than those of 30% GBN-100/M-LCER thermally conductive composites (λ of 1. 02 W/mK). At this time, the corresponding elastic modulus and hardness of gGBN-100/M-LCER composites increase from 2. 78 GPa and 0. 19 GPa to 4. 13 GPa and 0. 24 GPa, respectively.