Liquid crystal epoxy composites based on functionalized boron nitride: Synthesis and thermal properties

Abstract A composite was prepared by in‐situ polymerization of liquid crystal epoxy (LCE 4 ) with a low dielectric and high thermal conductivity boron nitride (BN) filler, which the filler (f‐BN) was surface‐functionalized by γ‐glycidoxypropyltrimethoxysilane (KH560) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (NH 2 ‐POSS). The surface‐functionalized BN was more uniformly dispersed in LCE 4 , which improved the interfacial compatibility between inorganic and organic phases. Compared with pure LCE 4 , KH560, and NH 2 ‐POSS modified f‐BN/LCE 4 composites exhibited a higher glass transition temperature, better thermal stability, and higher thermal conductivity. For example, when the f‐BN content reached 30 wt%, the energy storage modulus of the composite increased to 2580 MPa, and the glass transition temperature was 103°C. The thermal conductivity of this 30 wt% f‐BN composite was 0.48 W m −1 K −1 , 128.6% higher than that of pure LCE 4 . In addition, thermal stability, low hygroscopicity, and dielectric properties of the composites were characterized and analyzed to explore the application prospects of f‐BN/LCE 4 composites in electronic packaging and in high‐performance microelectronic devices.