硅/巯基复合改性光固化WPUA涂料制备及其性能

采用端羟基硅油（HS）、季戊四醇四-3-巯基丙酸酯（PETMP）先后改性紫外光固化水性聚氨酯丙烯酸酯（WPUA），探究了HS及PETMP添加量对涂膜性能的影响。FTIR表征了改性前、后产物的结构；测试了乳液粒径，并利用TEM和SEM对乳液形貌和涂层断面进行了分析。通过涂膜附着力、硬度、柔韧性、抗冲击、接触角、综合热分析、电化学阻抗谱及极化曲线等测试评价涂层的机械性能、疏水性、耐热性及防腐性能。结果表明：当HS及PETMP添加量分别为3%、5%时，硅/巯基复合改性的紫外光固化WPUA涂层相对于改性前，硬度由HB提升为3H，附着力由3级提升到1级，柔韧性为0.5mm，耐冲击为50cm，接触角由68.5°提升到90.5°，吸水率由18.78%降低为6.94%；涂层的热稳定性显著增强；涂层阻抗由1.86×10⁶Ω·cm²增大到6.45×10⁷Ω·cm²，E_coor由 -1.069V正移到-0.4215V，I_coor由2.12×10^-8A/cm²减小到8.11×10^-10A/cm²，年腐蚀速率为0.0242mm。表明HS及PETMP的引入显著提升了涂层的综合性能。

Preparation and properties of silicon and sulfhydryl compound modified UV-curable WPUA coating

Use hydroxy-terminated silicone oil (HS) and pentaerythritol tetra-3-mercaptopropionate (PETMP) to modify UV-curable waterborne polyurethane acrylate (WPUA) successively, and explored the addition amount of HS and PETMP influence on the properties of the coating film. The structures of the products before and after modification were characterized by FTIR, the particle size of emulsion was tested, and the morphology and coating cross section of emulsion were analyzed by TEM and SEM. The mechanical properties, hydrophobicity, heat resistance and corrosion resistance of the coating were evaluated by adhesion, hardness, flexibility, impact resistance, contact angle, comprehensive thermal analysis, electrochemical impedance spectroscopy and polarization curve. The results showed that when the addition of HS and PETMP were 3% and 5%, respectively, the hardness of UV cured WPUA coating modified by silicon/sulfhydryl composite increased from HB to 3H, the adhesion increased from level 3 to level 1, the flexibility was 0.5mm, the impact resistance was 50cm, the contact angle increased from 68.5° to 90.5°, the water absorption rate decreased from 18.78% to 6.94%, and the thermal stability of the coating was significantly enhanced. The coating impedance increased from 1.86×10⁶Ω·cm² to 6.45×10⁷Ω·cm², E_coor positively moved from -1.069V to -0.4215V, I_coor reduced from 2.12×10^-8A/cm² to 8.11×10^-10A/cm² with an annual corrosion rate of 0.0242mm. The introduction of appropriate amounts of HS and PETMP significantly improved the overall performance of the coating.