Waste Tetra Pak particles from beverage containers as reinforcements in polymer mortar: Effect of gamma irradiation as an interfacial coupling factor

In this work, composites based on polyester resin and silica sand were elaborated. Partial substitution of silica sand by waste Tetra Pak particles from discarded beverage containers was carried out, namely 1, 2, 4 and 6% by weight. As is well known, Tetra Pak packaging have six layers: four of polyethylene, one of cellulose and one of aluminum. Modified composites were irradiated with gamma rays at doses from 100 to 500 kGy in order to improve the mechanical properties of composites through a better interfacial coupling between the matrix and Tetra Pak particles caused by the irradiation process. The results shown an improvement of 15% on the compressive strength and 16% on the flexural strength, when 1% of Tetra Pak particles and irradiation dose of 100 kGy were used. Higher compressive and flexural deformation was also observed (until 34% higher); therefore a ductile material was obtained, which is not common for these kinds of composites. By increasing the irradiation dose to 200 kGy and concentration higher than 2% of waste Tetra Pak particles, mechanical properties of the composites decreased considerably.