Polycarbonates(PC)are widely used in the industry and the transparent parts of the strategic field,and the structure performance and the function of the PC can be improved by the surface coating.For the special service environment such as UV radiation,on the one hand,the protection performance of the PC substrate can be enhanced by the design of the film layer,and on the other hand,the service stability of the PC/coating system under the UV irradiation is affected by multiple factors(substrate degradation,interface adhesion,coating structure performance change).It is of great significance to study the performance of PC/coating under the UV irradiation and to control the UV stability of the film-based system by changing the compostion of coating.In this paper,a sol-gel method was used to prepare the Silicon-TiO2 hybrid coating on the surface of the PC.and the effect of the nano-TiO2 doping on the protective properties of the PC substrate was discussed.According to the surface cracking failure behavior of PC/Silicone-TiO2 samples.The relationship between the properties of the coating structure and the UV stability of the product was investigated by controlling the proportion of the silane components in the coating,and the solvent-stress cracking(ESC)property of the film-based system after the UV irradiation was further studied.The main tasks include:(1)The structural energy evolution and stability of the PC/Silicone-TiO2 system under UV irradiation were investigated.The results showed that:①the Silicone-TiO2 coating prepared had certain stratch protection and UV shielding effect on PC,and the adhesion of film-based interface after UV irradiation was better than that of Silicone coating.②The surface cracking of PC/Silicone-TiO2 under UV irradiation is mainly nano-TiO2,which has a certain photocatalytic degradation effect on the coating,and accelerates the evolution of the structure properties of the coating;through the regulation of the proportion of silane components in the coating,the structure of the linear Si-O-Si chain in the coating and the alkyl lateral base on the chain segment can be increased.On the one hand,slow down the degradation of TiO2 to the chain,on the other hand,improve the mechanical properties of the coating,so as to delay surface cracking and enhance the UV stability of the film-based system.(2)The ESC resistance of PC/Silicone-TiO2 system before and after UV irradiation was investigated.The results show that the ESC resistance of the product is related to the proportion of silane in the Silicone-TiO2 coating.The UV protection of the coating can delay the degradation of the substrate,which is beneficial to maintain the ESC resistance of the PC/coating system after UV aging.After UVB irradiation for 96 h,the coating cracked and lost the solvent barrier,but the ESC resistance of PC/Silicone-TiO2 was still better than that of PC. |