Exploring the simultaneous effect of nano-silica reinforcement and electron-beam irradiation on a model LDPE/EVA-based TPE system

Abstract

Background: The technical properties of polyolefinic thermoplastic elastomer (TPE) systems can be modified significantly using fillers like nano-silica. Controlled irradiation can potentially be an effective way of tailoring the technical properties of such nano-silica-filled TPE systems. Results: The effect of controlled electron-beam irradiation on the properties of a pristine silica nanoparticle-filled model low-density polyethylene/ethylene-(vinyl acetate) (LDPE/EVA) TPE system is explored in this paper. The morphology of such a filled system was investigated using scanning electron microscopy (SEM) and field-emission SEM. The dispersion of silica particles was analysed using transmission electron microscopy which clearly indicates that at low loading a fine dispersion of silica occurs in the polymer matrix. Swelling studies and Fourier transform infrared analyses indicate the occurrence of a favourable EVA-silica interaction. On the whole, it is observed that electron-beam irradiation induces a high degree of reinforcement in all the silica-filled samples through interfacial crosslinking as well as controlled crosslinking in the two polymer phases. In a few samples the processing characteristics are remarkably preserved following concurrent nano-silica reinforcement and irradiation, while the technical properties of TPE systems, including set, solvent swelling and mechanical properties, are improved. However, the improvement in properties is a strong function of sequence of addition of filler in the LDPE/EVA blends. Conclusion: The green technique studied can be potentially extended for the improvement of the technical properties of conventional TPE systems. © 2009 Society of Chemical Industry.