水性聚偏氟乙烯型反射隔热涂层的耐久性研究

研究了在酸、碱、盐和UV辐照等环境作用下水性聚偏氟乙烯型(PVDF)反射隔热涂层性能的时变规律。使用扫描电镜(SEM)和能谱分析表征了涂层微观形貌及断面中的氟元素分布,对涂层在经各类环境作用前后的明度、光泽、色差、力学性能和反射隔热性能进行了测试,并使用ATR-FTIR对表面涂层的官能团变化进行了分析。结果表明:氟元素在涂层树脂基体中的垂向分布较均匀;56 d UV处理会提升涂层光泽;经酸、盐和UV处理后,涂层明度未见明显变化且色差较小,涂层断裂伸长率降低且抗拉强度提升,最高达8.4 MPa,反射隔热性能指标未见明显变化;碱处理后的涂层出现明显的色差和明度下降,涂层变脆且抗拉强度下降,同时太阳光反射比由0.70降至0.65。ATRFTIR分析结果表明:涂层的耐酸、盐和UV能力较强,但在碱性条件下存在含氟组分的降解破坏情况。

Study on Durability of Waterborne Polyvinylidene Fluoride (PVDF) Reflective Thermal Insulation Coatings

The performance of waterborne polyvinylidene fluoride(PVDF) reflective thermal insulation coatings under various environmental conditions including acid,alkali and salt solutions and ultraviolet irradiation was studied. Scanning electron microscopy(SEM)and energy spectrum analysis were used to characterize the micromorphology of the coatings and the distribution of fluorine in the cross section. The changes of brightness,gloss,color difference,mechanical properties and reflective insulation performance of the coatings before and after various environmental exposures were tested. ATR-FTIR was used to analyze the changes of functional groups on the surface of coatings. The results showed that the vertical distribution of fluorine in the coating resin matrix was relatively uniform;the 56 days UV irridation increased the gloss of the coatings;after exposure to the acid and salt solutuions and ultraviolet irridation,the coatings brightness did not change significantly and the color difference was small. In the meanwhile,the elongation at break of the coating was reduced but the tensile strength was increased up to 8. 4 MPa. And no significant changes in the reflective insulation performance indicators was found. After treated with the alkali solution,the coatings showed a distinct color difference and a decreased brightness value,and became brittle with the tensile strength decreased. And the solar reflectance decreased from 0. 70 to 0. 65. ATRFTIR analysis results showed that the coatings indicated strong resistance to acid,salt and UV,but presented degradation of fluorine-containing components under alkaline conditions.