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

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.