Control of Protective Coating Performance Aspects Through Manipulation of Polymer Fragility

在环境条件下施涂的液体高性能保护涂层必须经历成膜以提供连贯的、粘附的和功能性的涂层膜，从而提供必要的性能。成膜的速率和程度在工艺方面（涂覆的制品可以多快地处理或储存）以及在涂层性能方面（已经形成了什么性质）都是最重要的。确保涂层具有可行的适用期，在经济的时间范围内干燥，并且在投入使用时涂层性能足够是成功成膜的重要组成部分。双组分热固性环氧-胺配方代表了大多数需要防腐或耐化学性的环境固化涂料技术。聚合物粘合剂中的所有反应性基团的完全转化在玻璃化至玻璃态发生之前在环境固化条件下很少实现，并且在扩散控制过程的一段时间之后，反应基本上停止。因此，涂料必须经常在欠固化状态下实现必要的性能。为了改善应用生产率与最终性能之间的理想平衡，更好地理解固化温度、反应基团的转化程度、聚合物结构和聚合物玻璃化转变（Tg）的选择聚合物玻璃脆性的概念与聚合物流动性随接近Tg的温度而变化的程度有关。“易碎”体系被描述为在接近Tg时聚合物迁移率变化大（伴随着大的热容变化）的那些，而“强”体系具有较低的迁移率（和较低的热容变化）。脆性量化了材料从液体到固体的变化速度，并且与聚合物链段填充效率有关，而聚合物链段填充效率又被认为与各种关键性能标准（特别相关的是机械性能和分子扩散阻挡性能）相关。通过选择反应组分，操纵聚合物的脆性，从而提供了一条路线来操纵干燥过程和最终的涂层性能criterions.We建议检查的假设，即聚合物的脆性可以通过聚合物的结构通过选择反应组分所带来的操纵。主要的环氧-胺粘合剂组分和其他常见的反应性添加剂在现代环氧-胺涂料配方中使用的影响，包括叔胺促进剂将explored.Using模型formulations，应用最先进的Modulated DSC方法将探索解释复杂的玻璃化转变区域。评估起始材料和相应的完全固化膜的热容量的变化将允许确定脆性的差异。应用E-Red技术将量化反应转化率，并探索聚合物结构、转化率和脆性之间的关系。将探索聚合物脆性对关键薄膜性能属性的影响。主要的干燥过程，以及与使用正电子湮没光谱（帕尔斯）或动态蒸汽吸附（DVS）的固化膜的透膜扩散分子传输性质和使用动态机械分析（DMA）的聚合物膜老化过程相关的那些。

Liquid applied, high performance protective coatings applied under ambient conditions must undergo film formation to deliver a coherent, adherent and functioning coating film to deliver the necessary performance. The rate and extent of film formation is of the highest importance both in terms of the process (how quickly a coated article can be handled or stored) and also in terms of coating performance (what properties have developed). Ensuring the coating has a workable pot-life, is dried in an economic timeframe and that coating performance is adequate when placed into service are vital components of successful film formation. Two component thermosetting epoxy-amine formulations represent the majority of ambient cured coating technology where corrosion protection or chemical resistance is required. Complete conversion of all reactive groups in the polymer binder is rarely achieved under ambient curing conditions before vitrification to the glassy state occurs and, following a period of diffusion controlled processes, reaction essentially stops. Consequently the coating must often achieve necessary performance in an under-cured state.In order to improve the desired balance of application productivity alongside final performance properties, greater understanding of the inter-relationships between cure temperature, extent of conversion of reactive groups, choice of polymer architecture and polymer glass transition (Tg) on coating film performance is required to guide design of coating formulations.The concept of polymer glass fragility is associated with the extent that polymer mobility changes with temperature close to Tg. "Fragile" systems are described as those that have large changes in polymer mobility close to Tg (accompanied by large heat capacity change) whereas "strong" systems have lower mobility (and lower change in heat capacity). Fragility quantifies how quick a material changes from liquid to solid and is related to polymer segment packing efficiency which, in turn, is believed correlated with various key performance criteria (of particular relevance is mechanical properties and molecular diffusion barrier properties). Through choice of reactive components, manipulation of polymer fragility may thus provide a route to manipulate both drying processes and final coating performance criteria.We propose to examine the hypothesis that polymer fragility can be manipulated through polymer architecture brought about through choice of reactive components. Influence of main epoxy-amine binder components and other common reactive additives used in modern epoxy-amine coating formulations including tertiary amine accelerators will be explored.Using model formulations, application of state-of-the-art Modulated DSC methodology will be explored to interpret complex glass transitions regions. Assessment of changes in heat capacity of starting materials and corresponding fully cured films will allow determination of differences in fragility. Application of Infra-Red techniques will quantify reaction conversion and allow relationships between polymer architecture, conversion and fragility to be explored.The implications of polymer fragility on key film performance attributes will be explored. Primarily drying processes, but also those associated with through-film diffusional molecular transport properties of cured films using Positron Annihilation Spectroscopy (PALS) or Dynamic Vapour Sorption (DVS) and polymer film aging processes using Dynamic Mechanical Analysis (DMA).