Investigation of gamma (γ) radiation and hygrothermal aging on the performance of hybrid natural/synthetic fiber reinforced thermoset polymer matrix composites

The study explores two critical factors affecting the performance of fiber-reinforced thermoset polymer composites: (i) the effect of gamma (γ) radiation as a post-treatment, and (ii) the effect of hygrothermal aging as a simulated service environment. Composite laminates were fabricated via compression molding using unsaturated polyester resin as the thermoset matrix, reinforced with jute (natural fiber), glass (synthetic fiber), and jute/glass hybrid formulation. The three laminate configurations examined were: (i) jute/polyester, (ii) glass/polyester, and (iii) hybrid jute/glass/polyester. In the first section of this study, the fabricated composites were subjected to γ-radiation at doses ranging from 1.0 kGy to 10.0 kGy. The effects of irradiation were assessed through tensile and flexural tests, Fourier Transform Infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM). Mechanical testing revealed an enhancement in tensile and flexural properties, with the most significant improvement observed at a dose of 5.0 kGy. In the second section of this study, non-irradiated composites were exposed to hygrothermal aging by immersion in water baths maintained at 23 and 60 °C for up to 70 days. Dynamic Mechanical Analysis (DMA) was employed to evaluate viscoelastic behavior, while FTIR provided insights into physico-chemical changes. Water uptake measurements revealed that hybrid laminates exhibited superior moisture resistance compared to neat jute/polyester composites. Overall, the findings suggest that these composite materials hold strong potential for various lightweight structural applications.