Flame retardancy and mechanical properties of silicone rubber foam composite reinforced with ZnNiAl layered double hydroxides

Herein, various of silicone rubber foam (SRF) composites containing tri-metallic zinc-nickel-aluminum layered double hydroxides (ZnNiAl-LDH) were fabricated though a dehydrogenative foaming strategy. The chemical composition and structure of ZnNiAl-LDH were characterized by a series of measurements. The incorporated ZnNiAl-LDH filler exhibited good dispersion level in SRF matrix, and the SRF-LDH1 possessed a denser pore structure. Taking advantages of the lamellar structure and catalytic function of ZnNiAl-LDH, the most efficient improvements in mechanical, thermal stability, and flame retardancy properties were achieved for the SRF-LDH1 composite containing 1 wt% of LDH. Particularly, the SRF-LDH1 exhibited significantly increase in tensile strength (36.8 kPa), elongation at break (50.2%), compression stress (65.3 kPa), limiting oxygen index (28.6%), and UL-94 rating (V0) than the pristine SRF. In addition, the SRF-LDH1 showed significantly reductions in THR (37.9%) and TSP (30.4%), and the relevant time of TTI and T PHRR delayed about 2 times, as compared to the SRF. The present work affords a new approach to prepare silicone rubber foam composite with improved application performances.