Insulating Polymer Composites with Ultrahigh Thermal Conductivity by Synergetic Effects of Boron Nitride Nanostructures

Description

[Importance of heat-dissipation materials]Especially in recent years, thermally conductive electrically insulating polymer composites are becoming extremely important as heat-dissipation electronic packaging materials and/or thermal interfacial materials for packaging LED, printed circuit boards, chips, solar cells, generators, motors and power modules etc.[High thermal conductivity of nano-sized BN]Boron nitride (BN) nanostructures (BN nanotubes & nanosheets etc.) are the best fillers for highly thermally conductive insulating polymer composites with a constant wide band gap, superb mechanical properties, great structurally stability, very strong anti-oxidation ability and, especially, a theoretical thermal conductivity up to ～3000 W/mK (Experimentally, electrically insulating multi-walled BN nanotubes with diameters of ～50 nm possess a thermal conductivity of 200-300 W/mK, which is close to 238 W/mK of aluminum and comparable to 390 W/mK of copper).[Our approach]We propose to utilize synergetic effects of BN nanotubes and BN nanosheets to achieve most effective improvement of thermal conductivity of insulating polymers. Synthesis methods for mass production of BN nanostructures, especially BN nanosheets will be developed. We will also work on synthesis of a hybrid BN nanostructure with BN nanosheets covalently attached on BN nanotubes to maximize synergetic effects and reduce interfacial thermal resistance effectively. Covalently bonded filler architectures will be built to maximize synergetic effects between BN nanotubes and nanosheets to promote effective formations of thermally conductive channels inside matrixes. Moreover, effective surface modification methods for BN nanostructures, including covalent bond functionalization and functionalization via weak interactions etc, will be adopted to improve interfaces between fillers and matrixes. Overall performances of composite materials fabricated will be thoroughly investigated.[Target]By this project, based on effective synergetic effects between BN nanostructure fillers, a variety of polymer composites with high thermal conductivity (expected to be 10-30 W/mK) will be fabricated. They should possess excellent overall performances, including low dielectric constant and loss, good mechanical properties, low coefficient of thermal expansion, well-preserved or improved high break-over voltage and great processibility etc.