Study on Aramid Nanofibers-Reinforced Epoxy All-Organic Composites With Enhanced Thermal Conductivity and Suppressed Thermal Expansion

In this study, the high-performance all-organic epoxy composites, aramid nanofibers/phenol-hydroxy polyphenylene ether resin/epoxy resin (ANFs/SA90/EP), were fabricated, and a systematic investigation was conducted on their dielectric, mechanical, thermal conductivity, and thermal expansion properties. Firstly, SA90 was introduced to modify epoxy resin, leading to a remarkable improvement in the toughness and thermal resistance of epoxy resin. Subsequently, ANFs were incorporated into the modified matrix to further improve the thermal conductivity and thermal expansion properties. The results indicated that the bending strength, modulus and thermal conductivity of the composite material reached 145 MPa, 3.48 GPa and 0.224 W·m⁻¹·K⁻¹, respectively, representing an increase of 12%, 10% and 30% compared to the pure epoxy. Meanwhile, the coefficient of thermal expansion (CTE) of the composite material dropped to 77.3 ppm·K⁻¹, a reduction of about 25% compared with pure epoxy. These significant improvements in performance are mainly attributed to the strong hydrogen bonding interactions formed between ANFs and the matrix, which significantly enhance the interfacial compatibility, thereby effectively improving the mechanical and thermal expansion properties. Moreover, the incorporation of ANFs established efficient thermal conduction pathways within the composite material, significantly enhancing its thermal conductivity. In addition, the incorporation of ANFs further optimized the dielectric properties of the composite material. At 1 MHz, the dielectric loss was reduced to merely 0.015, representing a decrease of approximately 32% compared to pure epoxy. This study provides innovative ideas and effective strategies for the development of all-organic epoxy packaging materials.