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

Abstract

Abstract A series of high temperature vulcanization (HTV) silicone rubbers with TiO2 ultraviolet (UV) shielding layer and polytetrafluoroethylene (PTFE) hydrophobic layer were prepared via stepwise spray method. It was found that the hydrophobic PTFE liquid emulsion (PTFEL) 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 TiO2 and PTEF solid powder (PTFES) 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-PTFEL/TiO2-PTFES 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-PTFEL/TiO2-PTFES coating HTV silicone rubber.