Effect of Silica Nanoparticles on the Local Segmental Dynamics in Polyvinylacetate

Abstract

The effect of nanosized silica particles on the properties of polyvinylacetate (PVAc) was investigated for a range of silica concentrations encompassing the filler network percolation threshold. The quantity of polymer adsorbed to the particles (“bound rubber”) increased systematically with silica content and was roughly equal to the quantity shielded from shear stresses (“occluded rubber”). A variety of experimental techniques was employed including pressure‐volume‐temperature measurements, broadband dielectric spectroscopy, thermal analysis (modulated DSC), dynamic‐mechanical spectroscopy, viscometry. The glass transition properties of PVAc, i.e. the glass transition temperature and the changes in the thermal expansion coefficient and heat capacity at Tg, as well as the isothermal compressibility and the volume sensitivity of the local segmental dynamics of the polymer chains in the presence of the polymer‐filler interface are discussed. The implication of this result and possible directions for new research are considered.