Abstract: While the enhancement of elastomer properties through nanofiller addition has been widely explored, developing high-performance elastomers for electrically insulating electromagnetic interference (EMI) shielding materials using a simple approach remains crucial. In this study, high-performance composite silicone rubber (SR) elastomers were fabricated through a combination of straightforward physical mixing and chemical grafting approach. Specifically, the incorporation of components aluminum trioxide nanoparticles (n-Al₂O₃) and reactive small molecule 2-isocyanoethyl acrylate (ICA) and 2-Amino-4-hydroxy-6-methylpyrimidine (UPY) into SR significantly improved both the mechanical strength and thermal resistance of the composites due to the synergistic effects of nanoparticles and hydrogen bonding. In addition, as flexible electronics become more complex and miniaturised, there is an increasing demand for stretchable electrically insulating EMI shielding materials. Liquid metal (LM) with extreme fluidity is ideal for the preparation of stretchable EMI shielding materials. By introducing LM, we prepared a stretchable electrically insulating EMI shielding material with a sandwich structure using a simple mechanical sintering and lamination process, and the EMI shielding properties of the material remained stable before and after stretching. The modified insulating layer has excellent elasticity and thermal stability, which ensures the normal use of the composite EMI shielding material under high temperatures and mechanical deformation conditions. This research provides valuable insights into the development of shielding materials with high-performance electrical insulation and strain-invariant EMI shielding behavior.

Key words: Modified silicone rubber, Ultra-stretchable, High-temperature resistance, Liquid metal, Electrically insulated strain-invariant EMI shielding