Accelerated testing methods for oxidative aging of polymeric composites

Controlling damage progression in oxidative environments is critical for enhancing the long-term durability of polymeric resins and composites. Traditional methods for characterization of these materials for their practical service life require several thousands of hours of isothermal aging. Therefore, there is a need for accelerated testing methods in order to reduce the prohibitive cost in this testing process. Both elevated temperatures and pressure environmental conditions can accelerate oxidative aging of the materials. This paper presents methods to characterize oxidation progress and damage growth in a polymeric matrix composite based on stress-assisted diffusion and sample miniaturization. In this approach, microscale specimens are fabricated using micro-fabrication techniques. The specimens are isothermally aged at controlled stress levels that accelerate both the oxidation and damage growth in the specimen. Coupling effects of temperature and stress on the oxidative aging are investigated based on the presented method. Due to the small scale of the specimen, the number of specimens that can be tested in parallel grows significantly. Micro-fabrication techniques also allow integration of instrumentation for measurement of the specimen response during aging, thereby reducing the additional effort, time and expense of acquiring and processing the data from the specimens during the traditional long-term aging tests.