Enhanced ablation resistance of Divinyl‐POSS modified additional liquid silicone rubber and its fiber reinforced composite

Abstract To further improve the ablation and thermal properties of silicon rubber composite materials, the 3, 13‐divinyloctaphenyl double‐decker polyhedral oligomeric silsesquioxane (DV‐DDSQ) modified additional vinyl‐terminated polydimethylsiloxane (VPDMS) was prepared, and the effect of high silica fiber reinforcement on the ablation properties of VPDMS was investigated. The results show that when 0.8phr DV‐DDSQ was added, the mass residual rate at 800°C of the composites increased from 40.6% to 51.0%. The linear ablation rate (LAR) as well as mass ablation rate (MAR) of the composites of the DV‐DDSQ modified VPDMS, the high silica fiber reinforced VPDMS composite (HSF/VPDMS composite) and the high silica fiber reinforced DV‐DDSQ modified VPDMS composite (HSF/DV‐DDSQ‐VPDMS composite) decreased dramatically compared with raw VPDMS, and it was 16.36%, 35.69%, and 37.17% bring down for LAR and 5.34%, 14.60% and 25.59% for MAR, respectively. The tensile strength and hardness of the DV‐DDSQ modified composites increased by 9.52% and 14.13%, respectively, while the elongation at break decreased by 5.99%, compared with the raw VPDMS.