Characteristic and Synthesis of High-Temperature Resistant Liquid Crystal Epoxy Resin Containing Boron Nitride Composite

Abstract

Five liquid crystal epoxy resins and composites containing flat boron nitride (f-BN) and spherical boron nitride (s-BN) were successfully synthesized. The chemical structures, crystal diffraction, and thermal conductivity of the liquid crystal (LC) epoxy composites were measured using Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC), X-ray, and Discovery Xenon Flash. In this study, the molecular arrangement of five LC epoxy resins and the thermal conductivity of their composites were carefully discussed. Several different amounts of flat boron nitride and spherical boron nitride were added to the five LC epoxy resins. The influence of nano-scale ceramic materials, f-BN, and s-BN, on the thermal conductivity of the LC epoxy resins, was studied. It is worth noting that the thermal conductivity of the spherical boron nitride composite demonstrated a better result than that of the flat boron nitride composite. In simpler terms, the thermal conductivity of the composites is closely related to the molecular arrangement of the LC resin and the amount of BN added. The results demonstrate that the SBPDAE/s-BN (60%) composite shows the highest thermal conductivity of 9.36 W/mK in the vertical direction. These data prove that the LC alignment of the matrix will greatly enhance the thermal conductivity of the composites.

Advancements in The Cross-Linking and Morphology of Liquid Crystals

“…As the quantity of this compound within the LC matrix rises, the composite's glass transition temperature escalates, accompanied by a notable increase in the thermal conductivity coefficient (λ). This is the result of controlled phonon scattering in the epoxy resin [75][76][77][78][79]. Its molecular orientation enables efficient heat transfer through phonon vibrations.…”

Low dielectric constant and highly intrinsic thermal conductivity fluorine‐containing epoxy resins with ordered liquid crystal structures

“…used 4,4′‐bis(4‐hydroxybenzyl) diaminophenyl diglycidyl ether (SBPDAE), cationic initiator (BMIM), and spherical BN (s‐BN) fillers to prepare the corresponding s‐BN/SBPDAE composites. When the amount of s‐BN was 60 vol%, the λ of s‐BN/SBPDAE composites was 9.36 W/(m·K), 45.8 times higher than that of pure epoxy resin (0.20 W/(m·K)) 25 . However, the introduction of excessive thermally conductive fillers would lead to high interfacial thermal resistance, resulting in severe phonon scattering, which is not conducive to improving the λ value 26 .…”

“…When the amount of s-BN was 60 vol%, the λ of s-BN/SBPDAE composites was 9.36 W/(m⋅K), 45.8 times higher than that of pure epoxy resin (0.20 W/(m⋅K)). 25 However, the introduction of excessive thermally conductive fillers would lead to high interfacial thermal resistance, resulting in severe phonon scattering, which is not conducive to improving the λ value. 26 Additionally, due to relatively high ε value (>4.0) of the thermally conductive fillers, the final ε values of the epoxy composites are often high.…”

Enhanced Anticarbonization and Electrical Performance of Epoxy Resin via Densified Spherical Boron Nitride Networks

“…18 Wu et al showed that the thermal conductivity of the SBN composites was better than that of flat BN composites. 19 However, there are few studies on the thermal conduction, electrical insulation, and flame-retardant properties of the SBN-enhanced polymer composites, especially in the case of high-voltage discharge. In this paper, densified epoxy-SBN composites were prepared using multiscale SBN as fillers.…”

“…Ren et al prepared SBN/polydimethylsiloxane composites using a spray-assisted self-assembly method with a thermal conductivity of 2.30 W m –1 K –1 . Wu et al showed that the thermal conductivity of the SBN composites was better than that of flat BN composites . However, there are few studies on the thermal conduction, electrical insulation, and flame-retardant properties of the SBN-enhanced polymer composites, especially in the case of high-voltage discharge.…”