Effect of nanostructured polyhedral oligomeric silsesquioxane on the physical properties of poly(vinyl alcohol)

An effective amphiphilic polyhedral oligomeric silsesquioxane (POSS) encapsulated poly(vinyl alcohol) (PVA) nanocomposite was successfully fabricated by solution blending method. Anionic octa(tetramethylammonium) (Octa-TMA) and poly(ethylene glycol) (PEG) were used as cage side groups in POSS (Octa-TMA-POSS and PEG-POSS) for the present study. Transmission electron microscopic analysis revealed the uniform dispersion of POSS in the PVA matrix. Crystallinity of PVA/POSS system was computed from differential scanning calorimetric studies. The effect of POSS on the mechanical, dynamic mechanical, and dielectric properties of PVA has been analyzed and discussed in detail with respect to the weight percentage of POSS. The incorporation of POSS in PVA matrix remarkably enhances the Young's modulus of the matrix. The viscoelastic properties such as storage modulus, loss modulus, damping behavior, and glass transition temperature of the membranes were evaluated. The relaxation corresponding to the crystal-crystal slippage characteristic of semicrystalline polymers were observed in storage modulus curves of PVA/POSS system, suggesting the crystalline nature of matrix even in the presence of POSS. Less polar, inert, and stiff inorganic center core of POSS contributes to the reduced energy dissipation and dielectric constant of PVA/POSS system. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45447.