Analysis of Physical and Chemical Deterioration of Polymeric Coatings for Structural Steel

本提案的目的是表征用于保护钢结构和桥梁的聚合物面漆和面漆系统的降解机制。分析将包括通过正电子光谱法确定纳米级缺陷尺寸分布和分布，这些缺陷尺寸分布和分布是从顶面和从与底漆和金属表面的界面开始的深度的函数;通过电子自旋共振检测、量化和识别与光降解和光氧化降解相关的自由基，这些自由基是实时老化和加速老化的函数;以及常见的光学和机械性能。样品将在紫外线、氧气和高温下进行加速老化，并在桥梁和其他结构上进行实际暴露。结果将结合起来，以了解结构钢涂层系统失效的降解机制。

The objective of this proposal is to characterize degradation mechanisms in polymeric topcoat and finish systems used to protect steel structures and bridges. Analyses will include determination by positron spectroscopy on nano-scale defect size profiles and distributions as a function of depth from the top surface and from interfaces with primers and the metal surface; detection, quantification and identification by electron spin resonance of free radicals associated with photo degradation and photo-oxidative degradation as a function of real-time and accelerated aging; and common optical and mechanical properties. Samples will be subjected to accelerated aging in ultraviolet light, oxygen and elevated temperature and to actual exposure on bridges and other structures. The results will be combined to develop an understanding of the degradation mechanisms responsible for failure of coating systems on structural steels.