Upcycling Waste Ground Tire Rubber in Waste Polyethylene Mixtures: The Role of Radiation Induced Grafting and Mixing Strategies

ABSTRACT

We investigated the properties of waste polyethylene and ground tire rubber (GTR) blends as a function of different mixing strategies and GTR surface modifications. The GTR surface was modified by ionizing radiation in air and by radiation induced grafting (maleic anhydride, MAH and methyl methacrylate, MMA). We confirmed the presence of oxygen‐containing functional groups by Fourier‐transform infrared spectroscopy (FTIR), and the formation of specific morphological structures by scanning electron microscopy (SEM). We prepared mixtures containing polyethylene and GTR using three different mixing methods. To improve mechanical compatibility, we used ethylene‐vinyl acetate copolymer (EVA), which improved the tensile strength by 25% and the elongation at break by 84%. The tensile strength of the sample containing GTR grafted with MAH increased by 30% relative to the reference sample (MMA 26%), while its elongation at break exceeded it by 158% (MMA 128%). Dynamic mechanical measurements revealed that although the addition of EVA reduced the damping coefficient, radiation treatment and grafting increased it. The SEM analysis indicated that strong adhesion and chemical compatibility had developed between the modified GTR and the matrix. The combined use of radiation‐induced grafting and blending sequence is an effective method for optimizing the properties of waste‐based polymer blends.