Dynamic mechanical relaxation of poly(2-hydroxyethyl acrylate)-silica nanocomposites obtained by the sol-gel method

Abstract

[EN] A series of poly(hydroxyethyl acrylate)-silica nanocomposites has been polymerized by the simultaneous sol-gel reaction of the organic monomer and the silica precursor tetraethyl orthosilicate (TEOS). Samples with different silica contents were prepared and their mechanical properties investigated by dynamic mechanical spectroscopy (DMS). The application of the time-temperature superposition principle to the isothermal DMS results in the main relaxation region permits to successfully construct master curves. The calorimetric properties of these hybrid materials have also been measured in order to compare the results of DMS and DSC The presence of a polymer phase formed by polymer chains with reduced mobility has been proved by the DMS results. The main relaxation due to the segmental dynamics of these chains takes place at frequencies around seven decades smaller than in the bulk PHEA homopolymer.