Effect of gamma irradiation on tensile, thermal and wettability properties of waste coffee grounds reinforced HDPE composites

This study investigates the impact of gamma irradiation on the properties of waste coffee grounds (WCG)/high-density polyethylene (HDPE) composites. The composites were manufactured with 20 wt% of unirradiated and irradiated WCG at 10 and 20 kGy doses of gamma radiation. Through the utilization of a two-roll mill followed by a hydraulic press. The properties of the composites were analyzed through several methods, including contact angle measurements, hardness and tensile tests, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), in order to understand the influence of gamma irradiation. The addition of WCG decreased the tensile strength of the composite. However, gamma irradiation at 10 and 20 kGy led to substantial improvements in thermal stability and tensile strength compared to unirradiated samples. The SEM images showed the alterations within the fiber-matrix interface that corroborated the enhanced tensile properties after the treatment. While FTIR spectra confirmed the changes in functional groups of WCG caused by the irradiation process, gamma irradiation treatment not only increases fiber-matrix adhesion but also significantly improves the water resistance of the composites. These results suggest that gamma irradiation can be used for the modification of agro-waste materials as a beneficial process and the fabrication of high-performance, environmentally friendly composites.