Thermally conductive and electrically insulating alumina-coated graphite/phthalonitrile composites with thermal stabilities

Alumina-coated graphite (Al2O3@graphite) core-shell particles were firstly synthesized by a liquid-phase chemical precipitation with the aid of sodium dodecyl sulfonate (SDS) surfactant using an inorganic precursor, then to fabricate thermally conductive and electrically insulating phthalonitrile composites by a hotcompression method. The obtained composite with 40 wt% Al2O3@graphite exhibited a thermal conductivity of 1.409 W/mK, 6.6 times that of pristine phthalonitrile matrix (0.214 W/mK). And the composites still retained electrical insulation below 20 wt% Al2O3@graphite content. Moreover, excellent thermal stabilities had been observed, compared with the glass transition temperature of pristine phthalonitriles (460 degrees C), the glass transition temperature of the composites decreased slightly but still high. Additionally, at 20 wt% content, the weight loss temperature (T-5 and T-10) and the char yield at 1000 degrees C (Y(c)1000) were 525 degrees C, 589 degrees C and 74.9% which was 8 degrees C, 14 degrees C and 3.1% higher than that of pristine phthalonitriles, respectively, which holds potential for use in the high temperature thermal management.

Automated summary

The study successfully synthesized Al2O3@graphite core-shell particles with excellent thermal conductivity and electrical insulation properties, and fabricated thermally stable phthalonitrile composites, which could potentially be used for high-temperature thermal management applications.