Synergistical Enhancement of the Processability, High‐Temperature Resistance, and Mechanical Properties of Silicone Resin Composite by Spherical Fillers

ABSTRACT This research explored the influence of silicone resin microspheres (SRMs) on the processing performance of silicone resin composites. In addition, the influence of hollow glass microspheres (HGMs) and precipitated silica on the high‐temperature resistance and mechanical properties of silicone resin composites was also studied. The results showed that SRMs expanded the processing window and enhanced processing performance of the composite. After adding SRMs, the spiral flow of the composite became more stable. The composite with 40 phr of SRMs had good fluidity between 120°C and 160°C, remaining consistent even with varied compression—molding times. The optimal SRM40‐HGM5 formulation significantly improved the lightweight, high‐temperature resistance, and mechanical properties of the silicone resin composites. Compared with SRM0, SRM40‐HGM5 exhibited reduced density by 20%, increased bending and impact strengths by 136% and 134%, respectively, and raised T _10% from 691°C to 791°C. After 100‐h thermal aging at 300°C, SRM40‐HGM5 retained as high as 87.35% of impact strength and 96.4% of bending strength. This study provides guidance for the development of high‐performance silicone resin composite materials in extreme environments.