The effect of microwave irradiation on the molecular diffusion of the ethyl acetate (EA) into the blend of styrene-butadiene rubber (SBR)/ethylene-propylene-diene monomer rubber (EPDM)

Abstract

The rubbers mix to prepare a blend to improve performance and reduce the costs of rubber-made articles. To achieve optimal mechanical and dynamical properties, strong interphases must form between different polymers in a blend. The solvent uptake into the structure of a polymer blend, whether organic or inorganic, is a significant concern in polymer-made articles. In this research, several blends and compounds based on styrene-butadiene rubber (SBR) and ethylene-propylene-diene monomer rubber (EPDM) were prepared. The prepared samples were pre-irradiated by microwaves and immersed in the ethyl acetate (EA) for doing the dynamic swelling experiment. The swelling results were used to determine the molecular diffusion characteristics of the polymer-solvent system. Also, a new method for quantitatively evaluating the interphase between two polymers in a blend was developed using the diffusion characteristics obtained from the swelling experiments. To validate the findings, conventional analytical techniques such as scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed. The diffusion parameters found in the study were used to determine the degradation mechanism of the immersed SBR/EPDM blend in an organic (EA) solvent and also, to develop a new technique for efficient separation of EA from a solution. In addition, the EPDM/SBR blend with a 20/80 wt ratio at 25°C associated with the lowest interphase showed the highest solvent uptake.