Novel ion-containing reverse osmosis membranes. I. Preparation and selected properties

Grafting and subsequent quaternization of 2- and 4-vinylpyridine to poly(vinyl chloride) (PVC) and to poly[3,3-bis(chloromethyl)oxetene], Penton, films have been exploited to prepare novel ion-containing membranes. 2-Vinylpyridine-grafted Penton films are the most attractive system for further study since the PVC grafts were unstable under the requisite extraction conditions. Although the sterically less hindered 4-vinylpyridine-grafted films were easier to quaternize, weight gain calculations indicated that complete quaternizations were only achieved with the 2-vinylpyridine-grafted films. High ionic concentrations were obtained in the grafted membranes. The mechanical properties of the wet films were measured. Salt absorption studies demonstrated that significant salt exclusion was achieved at relatively high salt concentrations although the grafted films sorbed up to 30 vol % water