Water Absorption Kinetics in Composites Degraded by the Radiation Technique.

Elena Manaila,Daniel Ighigeanu,Gabriela Craciun,Maria Daniela Stelescu

doi:10.3390/ma14164659

Abstract

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.

Highlights

The chemical structure of rubber can be changed in the production process through vulcanization, one of the desired effects being an increase in elasticity
The aim of the paper was to conduct a qualitative study on the kinetics of water absorption in composites based on natural rubber and plasticized starch, obtained by benzoyl peroxide vulcanization and irradiated with electron beam, in order to appreciate their degradation degree
Polymeric composites based on natural rubber and plasticized starch in amounts of 10 to 50 phr and obtained by benzoyl peroxide cross-linking were subjected to irradiation in the dose range from 150 to 450 kGy using an electron beam of 5.5 MeV in order to induce degradation

Summary

Introduction

The chemical structure of rubber can be changed in the production process through vulcanization, one of the desired effects being an increase in elasticity. One of the goals of devulcanization is rubber recycling, a difficult process that is still made by high heat and toxic chemical usage [1,2,3]. The molecular modifications of organic polymers induced by ionizing radiation lead to chain branching and cross-linking, causing the increase of molecular weight of the polymer, and chain scission or chemical degradation. These processes result in the breakage of the main chains of the macromolecule and a decrease of the molecular weight [4,5]

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Conclusion