Session: 03-09-01: Materials for Extreme Environments

Paper Number: 152571

152571 - Effects of Chlorine Exposure on the Mechanical Properties of Polymer Composites 

Thermoset-based polymer composites are extensively used in automotive and aerospace engineering due to their remarkable light weight, strength, durability, and resistance to various environmental conditions. During their service life, these materials are often exposed to multiple environments and chemicals that can affect their performance. While considerable research has been conducted on the effects of moisture absorption on the mechanical properties of these materials, the impact of exposure to certain chemical environments, such as chlorine-containing solutions, remains less understood. This study explores the effects of immersion in chlorine solution on the flexural and impact strengths of aerospace-grade polymer composites, with a focus on with a focus on understanding the diffusion and absorption behavior of chlorine and its impact on the composite’s mechanical performance.

The primary objective of the experiment was to determine the effect of chlorine concentration and exposure duration on the mechanical properties of E-glass/epoxy composites. The composites were molded and flexural specimens were prepared according to ASTM D790 standards. A set of composite samples were tested without exposure. Other sets were submerged in chlorine solutions of varying concentrations for three distinct time intervals: 48 hours, 2 weeks, and 1 month. The chlorine absorption by the specimens was tracked, and mechanical tests conducted to evaluate the changes in flexural and impact strength.

The results revealed that exposure to chlorine significantly deteriorates the flexural and impact properties of the glass/epoxy composites. A correlation between chlorine absorption and mechanical degradation was observed, with greater absorption leading to more pronounced property loss. The degradation was attributed to the weakening of the fiber-matrix interface and the deterioration of the composite matrix due to chlorine-induced chemical reactions. These findings underscore the importance of understanding the environmental effects on polymer composites in aerospace structures, especially in chlorine-rich environments. The study highlights the critical need for designers and engineers to account for long-term exposure to aggressive chemical environments when selecting materials and designing with composites for aerospace applications.

Presenting Author: Diego Zuniga University of Houston-Clear Lake

Presenting Author Biography: Diego Zuniga is a senior-year mechanical engineering student at the University of Houston-Clear Lake. He is also a research assistant working on polymer composites manufacturing, characterization, and service life prediction. His research is supported by the US Department of Education. Diego is a first-generation mechanical engineering students and very much appreciative to the funding agency to allow him to pursue research in the area of advanced manufacturing of composites.