Water Absorption Kinetics in Composites Degraded by the Radiation Technique

Rubber-based wastes represent challenges facing the global community. Human health protection and preservation of environmental quality are strong reasons to find more efficient methods to induce degradation of latex/rubber products in order to replace devulcanization, incineration, or simply storage, and electron beam irradiation is a promising method that can be can be taken into account. Polymeric composites based on natural rubber and plasticized starch in amounts of 10 to 50 phr, obtained by benzoyl peroxide cross-linking, were subjected to 5.5 MeV electron beam irradiation in order to induce degradation, in the dose range of 150 to 450 kGy. A qualitative study was conducted on the kinetics of water absorption in these composites in order to appreciate their degradation degree. The percentages of equilibrium sorption and mass loss after equilibrium sorption were found to be dependent on irradiation dose and amount of plasticized starch. The mechanism of water transport in composites was studied not only through the specific absorption and diffusion parameters but also by the evaluation of the diffusion, intrinsic diffusion, permeation, and absorption coefficients.