The rapid development of aerospace and other fields has driven a revolution in electronic packaging materials, and in the development of integrated circuits, it is critical to develop electronic packaging materials with high reliability and performance to withstand more extreme operating environments. To this end, a new benzoxazine hyperbranched silicone resin based on the high designability characteristics of hyperbranched silicone structure was designed in this paper, and its rapid moulding characteristics can fill in the gaps of conventional silicone resins in this application. The combination of benzoxazine group and hyperbranched silicone resin can provide the advantages of both, and the introduction of silicon-oxygen bond with high bond energy can improve the oxidation- and ablation-resistance of traditional organic resin materials. The benzoxazine ring can effectively improve the processing performance and mechanical properties of silicone resin materials, thus solving the problems of traditional organic resin materials (e.g., poor oxidation- and ablation-resistance) and the organic silicon material (e.g., difficult to process and poor mechanical properties). Due to the low entanglement and the high intramolecular free volume of hyperbranched polysiloxane chain segments, the prepared benzoxazine hyperbranched polysiloxane resin has the characteristics of low viscosity. At the same time, its initial curing temperature was only 163 ℃, and the activation energy of curing was 93.25 kJ•mol⁻¹, so the curing activity was significantly improved, and the processing performance was greatly enhanced. Moreover, the introduction of silicon-oxygen bond and high cross-linked structure gives benzoxazine hyperbranched polysiloxane cured products excellent temperature-resistance and ablation-resistance performance. Its glass-transition temperature was more than 270 ℃, its 5% decomposition temperature was higher than 410 ℃, the residual carbon rate was more than 78% in 1000 ℃ nitrogen and more than 35% in oxygen, demonstrating significant improvement compared with the existing electronic packaging moulding compound substrates. In addition, it also shows good fire-resistance (not burning in open flame), water-resistance (water absorption rate<1%) and electrical insulation. This study provides a new idea for the development of new temperature-resistant rapid moulding materials and high-performance packaging materials.

Key words: hyperbranched silicone resin, benzoxazine, functional modification, rapid moulding, high-performance encapsu-lation materials