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

这项建议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理。分析将包括用正电子能谱仪测定纳米级缺陷的尺寸轮廓和分布，作为从顶表面以及从与底漆和金属表面的界面的深度的函数；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；作为实时和加速老化的函数；以及常见的光学和机械性能。样品将在紫外线、氧气和高温下加速老化，并实际暴露在桥梁和其他结构上。这些结果将结合在一起，以加深对导致结构钢涂层系统失效的退化机制的理解。

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.