Synergistic Effects of Enviromental Exposures on Ploymer Matrix with or without Metallic Coating Protection

Epoxy and vinyl ester resins are widely being used in fiber-reinforced polymer matrix composites due to their superior physical and mechanical properties; however, they suffer significant degradation during prolonged environmental exposure that is affecting their extended use. The current study shows that the synergistic exposure to ultraviolet radiation, high temperature, and moisture has detrimental effects on the microstructure, strength, ductility, and toughness of both resins with more pronounced effects on the epoxy. The environmental damage in the microstructure of epoxy appeared primarily in the form of surface cavities and blisters while for the vinyl ester emerged mainly as microcracking events. Correlation between degradation of microstructure and loss in the flexural properties of epoxy and vinyl ester was also presented. Furthermore, the protective effect of copper metallic thin films on the epoxy substrate was characterized, revealing that the copper coating can be an effective barrier in preventing environmental degradation of epoxy based composites