Abstract
The effect of pristine silica nanoparticles on a model low‐density polyethylene (LDPE)–ethylene vinyl acetate copolymer (EVA) thermoplastic elastomer blend system is explored in this article. Pristine silica nanoparticles were melt‐blended with the LDPE–EVA system at 1.5, 3, and 5 wt % loadings through the variation of the sequence of addition. In one of the compositions, coupling agent bis[3‐(triethoxysilyl)propyl] tetrasulfide (Si‐69) was used to improve the interaction of hydrophilic silica fillers with the polymer matrix. The blends were compression‐molded, and their mechanical, dynamic mechanical, and thermal properties, X‐ray diffraction patterns, and morphology were evaluated. The properties of the blends were found to be strong functions of the sequence of addition of nanofillers during their preparation. With Si‐69 as a coupling agent, the dynamic storage modulus of nanosilica‐based composites was found to increase up to 35%. An appreciable improvement in the tension set properties of the thermoplastic elastomer nanocomposites was observed in all the nanosilica‐based films. Morphological studies and dynamic properties clearly indicated that the differential properties of these blend systems primarily stemmed from the extent of dispersion and alternation of crystalline morphology, which in turn was a strong function of preferential incorporation in the LDPE or EVA matrix and the agglomeration tendency of the nanofillers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008