Aqueous solution‐assisted in‐situ polymerization for fabrication of <scp>BNNS</scp>/<scp>PA12T</scp> nanocomposites with excellent thermal conductivity and mechanical properties

Abstract Maintaining uniform dispersion of nano filler under high content is critical for fabricating polymer‐based composites with great mechanical and thermally conductive properties. In this work, BNNS/PA12T nanocomposite with the highest boron nitride nanosheet (BNNS) content of 23.1 wt% was successfully prepared by the aqueous solution‐assisted in‐situ polymerization method. Results demonstrate that the BNNS can be uniformly dispersed in the composite due to the low viscosity during the polymerization process. As a result, when the content of BNNS is 23.1 wt%, the mechanical properties and thermal conductivity of BNNS/PA12T nanocomposite are 62 MPa and 1.55 W/(m·K). Furthermore, the composites also possess excellent high‐temperature resistance with the coefficient of thermal expansion (CTE) of 60 ppm/°C, about one third of pure PA12T, and the thermal deformation temperature also reaches 139.4°C. Therefore, the fabricated BNNS/PA12T nanocomposite can be effectively applied as thermal management and packaging materials for electronic devices. Highlights BNNS/PA12T nanocomposites were prepared by aqueous solution‐assisted method. BNNS can be uniformly dispersed at the filling content up to 23 wt%. The thermal conductivity of BNNS/PA12T nanocomposite can reach 1.55 W/(m·K). Possessing excellent mechanical properties and dimensional stability. The nanocomposite can be effectively applied for thermal management.