Effect of Controlled Electron Beam Irradiation on the Rheological Properties of Nanosilica-Filled LDPE-EVA Based Thermoplastic Elastomer

The effect of controlled electron beam irradiation on the rheological properties of a model LDPE-EVA thermoplastic elastomer (TPE) system filled with silica nanoparticles is explored in this article. The pristine silica particles were mixed with LDPE-EVA system in molten condition by varying the sequence of addition and amount of nanosilica. In one composition, Si69 was used to improve the state of dispersion of nanosilica. The rheological behavior of irradiated TPE systems is influenced remarkably by irradiation dose, loadings of silica, variation of sequence, and addition of Si69. All filled TPE systems register an increase in elastic response with increasing frequency and with increase in irradiation dose. Upon irradiation, melt viscosity increases when compared with the unirradiated samples because of the crosslinking effect and improvements in interfacial bonding. The viscoelastic response varies markedly with the temperature. The radiation sensitizing effect of silica is reflected from the rheological data. The dynamic and steady shear rheological properties do not follow a simple correlation. Finally, the rheological behavior is correlated with the morphology of the irradiated systems processed at various shear rates. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119:2153-2166, 2011