Investigation of Thermal Aging Behaviour on Silane Treated White Fumed Silica/Glass Fiber Reinforced Vinyl Ester Composite

Abstract

In this study, an investigation has been performed on the glass fiber-vinyl ester composites with varying contents of silane treated white fumed silica at different thermal aging conditions. The main objective of this research work is to explicate the effectiveness of silane treated functional fumed silica on commercially used glass fibre-vinyl ester composite at elevated temperature aging conditions. The fumed silica was treated with 3-Aminopropyltrimethoxysilane (APTMS) and the composites were made by a hand layup principle. The composites were further subjected to temperature aging such as 50 & 60 °C @ 180 days and tested for their mechanical, flammability, and water absorption properties. The results indicate that, despite thermal aging the mechanical properties of the composites is stable, revealing the enhanced silane protection effect on glass fiber and fumed silica. Composite GST21, GST22, and GST23, subjected to thermal aging at 60 °C for 180 days, the tensile and flexural strengths experienced reductions compared to the un-aged specimens. However, the decrease in values is minimal, indicating the resilience of the composites even under harsh aging conditions. Flammability tests revealed consistent UL 94 ratings for all specimens, even after thermal aging. Water absorption percentages marginally increased after thermal aging, particularly at higher temperatures, yet remained within acceptable limits. SEM analysis provided visual evidence of the composite's microstructure, highlighting areas of voids, crack formations and low fiber pull-out. Despite some indications of degradation, the overall integrity of the composites remained sound, emphasizing the effectiveness of silane treatment on glass fiber and fumed silica in maintaining structural stability.In summary, while some minor losses in mechanical and physical properties were observed in the thermally aged specimens, the silane treated glass fiber and fumed silica mitigated these effects, ensuring that the composites retained their essential characteristics. Overall, the study underscores the importance of silane barrier protection on the reinforcement materials in enhancing the durability and performance of composite materials, even under challenging conditions.