Highly efficient thermal conductivity of polyarylene ether nitrile composites via the introduction of hybrid fillers and tailored cross-linked structure

Polymer dielectrics with high thermal conductivity (λ) and excellent insulating properties are of interest in miniaturized and integrated electronic devices. However, most polymers are unable to fulfill this need due to their inherent structure. In this work, a polymer alloy with balanced thermal conductive and dielectric properties was successfully prepared by polyarylene ether nitrile(PEN), bisphthalonitrile-microsphere@boron nitride nanosheets(Bm@BNNS), and silicon carbide whisker (SiCws) at different scales. Specifically, introduction of Bm@BNNS fillers with core-shell structure into PEN resins results in heterogeneous interfaces, which effectively reduces the agglomeration and dosage of BNNS and synergistically improves the λ and dielectric performance. Besides, it has high breakdown strength (Eb) and high energy storage density (242.26kV/mm, 1.66J/cm3) when filled with only 4.37 vol% BNNS compared to pure PEN. Furthermore, effects of one-dimensional SiCws at different scales on formation of heat-conduction pathways and electrical insulation properties of PEN/Bm@BNNS composites were investigated. The findings display that PEN/Bm@BNNS/SiCws composites with large size SiCws (7.81 vol%) achieved a high λ of 2.376 W/m.K, which was 135.24% and 87.09% higher than pure PEN and PEN/Bm@BNNS composites, respectively. Thus, the thermal conductive pathways are constructed by line-plate structure (SiCws-BNNS), and insulating performance primarily on the core-shell structure (Bm@BNNS). Besides, the novel PEN/Bm@BNNS/SiCws hybrid materials are together with a low coefficient of thermal expansion of 38-89 ppm/°C and high Tg of 220 °C. Thus, it gives a promising insight to achieve highly λ polymer-based insulating film materials used for high-temperature-resistant fields.