Functionalized Aluminum Nitride for Improving Hydrolysis Resistances of Highly Thermally Conductive Polysiloxane Composites

Abstract A series of divinylphenyl-acryloyl chloride copolymers (PDVB- co -PACl) is synthesized via atom transfer radical polymerization employing tert-butyl acrylate and divinylbenzene as monomers. PDVB- co -PACl is utilized to graft on the surface of spherical aluminum nitride (AlN) to prepare functionalized AlN (AlN@PDVB- co -PACl). Polymethylhydrosiloxane (PMHS) is then used as the matrix to prepare thermally conductive AlN@PDVB- co -PACl/PMHS composites with AlN@PDVB- co -PACl as fillers through blending and curing. The grafting of PDVB- co -PACl synchronously enhances the hydrolysis resistance of AlN and its interfacial compatibility with PMHS matrix. When the molecular weight of PDVB- co -PACl is 5100 g mol −1 and the grafting density is 0.8 wt%, the composites containing 75 wt% of AlN@PDVB- co -PACl exhibit the optimal comprehensive performance. The thermal conductivity ( λ ) of the composite is 1.14 W m −1 K −1 , which enhances by 20% and 420% compared to the λ of simply physically blended AlN/PMHS composite and pure PMHS, respectively. Meanwhile, AlN@PDVB- co -PACl/PMHS composites display remarkable hydrothermal aging resistance by retaining 99.1% of its λ after soaking in 90 °C deionized water for 80 h, whereas the λ of the blended AlN/PMHS composites decreases sharply to 93.7%.