Flexible silane‐functionalized <scp>boron nitride</scp> filled polymer composite with high thermal conductivity and electrical insulation

Abstract Boron nitride (BN) has excellent thermal conductivity (TC), however, it exhibits high surface energy, strong chemical inertness, poor interface compatibility with polymer matrices, and difficulty in even dispersion within‐polymer matrix, preventive effective construction of TC pathways. Four kinds of modified boron nitride/polyurethane composites (BTPUC) were prepared by different silane‐functionalized BN with polyurethane (TPU). Among them, 3‐trimethoxysilylpropylmethacrylate (TMSPMA)‐functionalized BN demonstrated better interface compatibility with TPU, significantly improving the mechanical properties and TC of the composites compared to the other three functionalized BN addition. The BN@TMSPMA/PU exhibited good TC and mechanical properties, with a TC of 0.865 W/mK, a tensile stress and a tensile strain of 9.65 ± 1.40 MPa and 759.88 ± 67.93%, respectively. It also showed good electrical insulation properties and mechanical durability. Therefore, the as‐prepared BN@TMSPMA/PU have broad prospects as flexible thermal‐management materials. Highlights The composites are constructed by TMSPMA‐modified BN and polyurethane by NIPS. The composites show good mechanical properties and cyclic failure resistance. The composites exhibit good thermal conductivity and electrical insulation.