The degradation and weathering of modern polymer coatings: assessment and monitoring of the chemical signature

现代聚合物涂料的降解和风化：化学特征的评估和监测

• 批准号: RGPIN-2019-04827
• 负责人: Muehlethaler, Cyril
• 金额: $ 2.04万
• 依托单位: Université du Québec à Trois-Rivières
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=714949
• 关键词: degradation; weathering; modern; polymer; coatings

Polymer coatings are extremely common in our environment and used for protection, decoration or even sanitation of surfaces and objects. Understanding their structure-property relationship, rheology, surface chemistry, and degradation is therefore important for industry (e.g. control of production, durability, and performance), and other related fields such as art and conservation science (e.g. restoration, identification of counterfeited paintings) and criminal investigations (e.g. comparing the composition of suspected and reference paints in case of burglaries (tool paint, domestic paint), vandalism (spray paint), or car accidents (automotive paint)). Each of these fields, although facing distinct problematics, have one common analytical challenge: the coatings under analysis will potentially be subject to weathering and degradation over their lifetime. Through being exposed to the exterior environment, polymer coatings age, degrade, and acquire an altered chemical signature. The challenge for the scientific community is to understand these variations in order to predict the long-term weathering of polymer coatings. The weathering and degradation of paints is nonetheless a difficult task to apprehend, as the matrix is a dynamic medium. The degradation is a combination of many factors, including the migration or evaporation of components, and some physico-chemical modifications of the structure (oxidation, cross-linking). All these effects can further be catalyzed by heat, water (moisture), UV radiation, or biological/chemical contaminants. Additionally, the most common paint materials (i.e. acrylic, alkyd, polyurethane, polyester) have different rheologic properties and surface chemistry, and contain UV protection (hindered amines light stabilizers, HALS), heat stabilizers, mechanical modifiers, or anti-microbial additives that all contribute to their chemical signature and further increase the complexity of comprehensively evaluate their degradation. A survey of the literature shows that there is an important lack of knowledge on the degradation of polymer coatings, which has always been approached by case studies or specific applications, but remains incompletely understood at a more general level. In my Discovery research program, I intend to answer the following objectives: 1) Thorough evaluation of the influencing factors that contribute to degradation and their physical and chemical outcomes, 2) Assessment of the dating potential by a synergistic approach of the influencing factors using natural and accelerated weathering, 3) Creation of a comprehensive database of chemical signatures organized by paint compositions, analytical methods, and degradation conditions. This research will establish new analytical standards for the degradation of polymers in collaboration with the industry. Additionally, collecting and sharing the results through a database will have a direct and lasting impact on the scientific community.

聚合物涂层在我们的环境中非常普遍，用于保护，装饰甚至表面和物体的卫生。因此，了解它们的结构-性质关系，流变学，表面化学和降解对于工业（例如生产，耐久性和性能控制）以及其他相关领域(例如艺术和保护科学（例如修复，鉴定伪造画作）和刑事调查（例如在入室盗窃（工具漆，家用漆），故意破坏（喷漆）的情况下比较可疑油漆和参考油漆的成分），或者车祸（汽车油漆）。尽管这些领域面临着不同的问题，但它们都有一个共同的分析挑战：所分析的涂层在其使用寿命期间可能会受到风化和降解的影响。通过暴露于外部环境，聚合物涂层老化，降解，并获得改变的化学特征。科学界面临的挑战是了解这些变化，以便预测聚合物涂层的长期风化。然而，涂料的风化和降解是一项难以理解的任务，因为基质是一种动态介质。降解是多种因素的综合，包括组分的迁移或蒸发，以及结构的一些物理化学修饰（氧化、交联）。所有这些效应都可以通过热、水（湿气）、紫外线辐射或生物/化学污染物进一步催化。此外，最常见的涂料材料（如丙烯酸、醇酸、聚氨酯、聚酯）具有不同的流变性能和表面化学性质，并且含有防紫外线（受阻胺光稳定剂、HALS）、热稳定剂、机械改性剂或抗菌添加剂，这些都有助于它们的化学特征，进一步增加了综合评估其降解的复杂性。对文献的调查表明，聚合物涂层降解的知识严重缺乏，这一直是通过案例研究或特定应用来解决的，但在更普遍的水平上仍然没有完全理解。在我的“发现”研究项目中，我打算回答以下目标：1)全面评估导致降解的影响因素及其物理和化学结果；2)利用自然和加速风化作用的影响因素的协同方法评估定年潜力；3)创建一个综合的化学特征数据库，根据油漆成分、分析方法和降解条件进行组织。这项研究将与工业界合作建立聚合物降解的新分析标准。此外，通过数据库收集和分享结果将对科学界产生直接和持久的影响。