Equilibrium swelling measurements on crosslinked poly(2-hydroxyethyl methacrylate) (PHEMA) in water/dioxan mixtures show that the swelling exceeds that in pure water except in mixtures of very low water content. From the maximum swelling in water/dioxan (34/66 wt%) a value of 29 (kJ dm** minus **3) ** one-half is derived for the solubility parameter of PHEMA. Refractometric analysis of residual solvent shows the composition of solvent within the gel to be the same as that of the initial swelling medium only when the latter contains ca. 35 wt% water. For swelling in solvents of lower and higher water contents there are selective adsorption and selective desorption respectively of water to the gel. The results accord with published findings relating to dilute solutions of linear PHEMA in water/dioxan.
|Number of pages||3|
|Journal||Polymer communications Guildford|
|Publication status||Published - 1 Aug 1987|