Preparation of HTV silicone rubber with hydrophobic–uvioresistant composite coating and the aging research

A series of high temperature vulcanization (HTV) silicone rubbers with TiO 2 ultraviolet (UV) shielding layer and polytetrafluoroethylene (PTFE) hydrophobic layer were prepared via stepwise spray method. It was found that the hydrophobic PTFE liquid emulsion (PTFE L ) could steadily and tightly adhere to the HTV silicone rubber surface by spray method after pre-mixing with permanent room temperature vulcanized (PRTV) silicone rubber during the first step spray. And the subsequent introduction of TiO 2 and PTEF solid powder (PTFE S ) could improve the UV shielding ability and further increase the hydrophobicity of HTV silicone rubber during the second step spray after pre-blending. The accelerated hygrothermal aging process and UV aging process were used to analyze the effect of coating structure and composition on anti-aging performance. And the results indicated that the HTV silicone rubber with PRTV-PTFE L /TiO 2 -PTFE S composite coating showed a favorable UV shielding ability and also possessed an excellent hydrophobicity due to the introduction of low surface energy matter and the building of coarse micro-nano hydrophobic structure. After the aging process, the cracked micro-surface, increased water absorption and decreased mechanical property were displayed for the neat HTV silicone rubber, and these aging phenomena got dramatically improved for PRTV-PTFE L /TiO 2 -PTFE S coating HTV silicone rubber. Graphical abstract High temperature vulcanization silicone rubber with hydrophobic–uvioresistant composite coating built by stepwise spray method showed a micro-nano structure and displayed the favorable hydrophobicity and ultraviolet shielding capability.