Poly(methyl acrylate)/poly(hydroxyethyl acrylate) sequential interpenetrating polymer networks. Miscibility and water sorption behavior

Sequential poly(methyl acrylate)/poly(hydroxyethyl acrylate) interpenetrati ng polymer networks with different poly(hydroxyethyl acrylate) contents wer e prepared by free radical polymerization of hydroxyethyl acrylate inside t he previously polymerized poly(methyl acrylate) network. Differential scann ing calorimetry on dry samples shows that the interpenetrating polymer netw orks exhibit phase separation, and no differences are found between the gla ss transition temperatures of the two phases present in the interpenetratin g polymer network and those of the pure components. Thermally stimulated de polarization current experiments were used to study the influence of water sorption on the mobility of the different molecular groups in the poly(hydr oxyethyl acrylate) phase of the interpenetrating polymer network. Isotherma l water sorption of the interpenetrating polymer networks and pure poly(met hyl acrylate) and poly(hydroxyethyl acrylate) networks is analyzed with dif ferent theories to compare the behavior of the poly(hydroxyethyl acrylate) phase in the interpenetrating polymer networks with that of the pure poly(h ydroxyethyl acrylate) network. Diffusion coefficients of water in the inter penetrating polymer networks are obtained by means of dynamic sorption expe riments. (C) 1999 John Wiley & Sons, Inc.