新型文物封护保护材料氟橡胶耐紫外性能研究

封护措施对文物保护修复具有重要的意义,封护保护能有效阻隔环境因素(水分、氧气、空气污染物)对文物的影响,提高文物的耐腐蚀性。目前丙烯酸树脂B72和有机硅在文物封护领域应用较多,它们对于馆藏文物的保护有显著的效果,但它们的耐紫外性能不佳,不能很好地满足户外文物长期保护的要求。近年来氟碳材料由于具有优异的耐候性和耐老化性,已逐渐受到文物保护工作者的重视,本工作选择了一种新型氟碳材料F2311型氟橡胶作为研究对象,近年来已有将氟橡胶应用于金属文物、陶器、彩绘、壁画等文物封护保护的报道,但报道多侧重于应用,未见从理论方面验证或考察氟橡胶保护效果的研究。为了研究氟橡胶的耐老化性和在文物封护领域的适用性,本工作选用了丙烯酸树脂B72和2种有机硅涂料(分别为正硅酸乙酯和工业成品KSE-OH300)作为性能对比研究,通过紫外加速老化实验对它们进行了长期老化测试,利用红外、接触角、色差仪进行了结构和性能表征。结果表明:1)新型氟碳材料氟橡胶具有较优的紫外线耐受性,其在长期的紫外照射作用下颜色、结构和疏水性能均未发生明显变化,推测氟橡胶能够长期用于文物户外或户内封护保护,特别是针对处于复杂存储环境的文物保护有广阔的应用前景;2)B72在紫外照射下会发生氧化降解行为,红外证明这种降解反应在紫外照射初期就开始发生了,B72在紫外光下氧化降解导致封护膜发生黄变,在文物表面造成色差,推测B72不适用于户外文物的长期封护保护;3)2种有机硅类材料成膜后疏水性能一般,且在紫外辐射下结构趋于不稳定,外观也会发生黄变,推测这2种有机硅同样不适用于户外文物的长期封护保护。本工作通过评估材料的耐紫外性能来考察它们的耐老化性和在文物封护领域的适用性,研究结果表明新型氟碳材料氟橡胶与B72和2种有机硅相比,具有更优的紫外线耐受性,该考察结果可为文物封护材料的选择提供参考。

Ultraviolet stability of innovative fluoroelastomer coating for cultural relic conservation

Coating measures are of great significance to the conservation and restoration of cultural relics. Coating protection can effectively block the impact of environmental factors(moisture, oxygen, air pollutants) on cultural relics and improve their resistance to corrosion. At present, acrylic resin B72 and silicone are widely used in the field of cultural relic conservation. They have significant effects on the conservation of cultural relics in collections, but their UV resistance is not good and cannot well meet the requirements of long-term conservation of outdoor cultural relics. In recent years, fluorocarbon materials have gradually attracted the attention of cultural relic conservators due to their excellent weather and aging resistance. In our study, we selected a new type of fluorocarbon material-F2311 fluoroelastomer-as the research object. Recently, there have been reports on the application of fluoroelastomers to the conservation of cultural relics such as metal, pottery, and polychrome ones, as well as murals, but the reports mostly focus on applications;that is, there are few studies to verify or investigate the conservation effects of fluoroelastomers from a theoretical perspective. In order to determine the resistance to aging of a fluoroelastomer and its applicability in the field of cultural relic conservation, the F2311 fluoroelastomer, the acrylic resin B72 and two kinds of silicone coatings(TEOS and industrial product KSE-OH300), were selected for a performance comparison study. They were tested for long-term aging through accelerated ultraviolet aging experiments, and their structure and performance were characterized in terms of infrared spectra, contact angles and color differences. The results show that: 1) the fluoroelastomer F2311 had excellent UV resistance, and its color, structure and hydrophobic property did not change significantly under the action of long-term ultraviolet irradiation. It is speculated that this fluoroelastomer can be used for long-term outdoor or indoor cultural relic conservation, especially in complex storage environments;2) B72 underwent oxidative degradation under ultraviolet irradiation and this degradation reaction started at the beginning of ultraviolet irradiation, which was proved by corresponding infrared spectra. The oxidative degradation of B72 under ultraviolet light led to the yellowing of the sealing film and caused color differences on the surface of cultural relics. It is speculated that B72 is not suitable for long-term conservation of outdoor cultural relics;3) the hydrophobic properties of the two kinds of silicone materials were average after film formation, the structures were prone to becoming unstable under ultraviolet radiation, and they also became yellow. It is speculated that these two kinds of silicones are also not suitable for long-term conservation of outdoor cultural relics. This study evaluated the UV resistance of the materials to investigate their aging resistance and their applicability in the field of cultural relic conservation. The results indicate that the new coating material, the fluoroelastomer F2311, has better UV resistance than B72 and the two kinds of silicones. This work could provide references for the selection of coating materials for cultural relics.