Performance changes of composite membranes prepared from various glycidyl methacrylate derivatives and their mixtures

To produce membranes having desired salt rejection and water permeability properties for the reverse osmosis process, their active layers were fabricated from various gylcidyl methacrylate derivatives, i.e., 2,2-bis[3,5-dimethyl,4-(2-hydroxy-3-methacryloyloxy propoxy)phenyl]propane (TM-Bis-GMA), 4-cumylphenoxy glycidyl methacrylate (CP-GMA) and 4-tert-butylphenoxy glycidyl methacrylate (t-BP-GMA), by photopolymerization. Composite membranes prepared from TM-Bis-GMA exhibited better salt rejection and water permeability performance than those prepared by interfacially reacting m-phenylenediamine (MPDA) and trimesoyl chloride (TMC). The crosslinking density of the active layer was controlled by varying the mixing ratio of TM-Bis-GMA containing vinyl moieties at both ends of the molecule and CP-GMA (or t-BP-GMA) containing a vinyl moiety at the end of the molecule. The salt rejection of the membranes was higher than 99% when the active layer was fabricated from the mixtures containing less than or equal to 10 wt.% of CP-GMA (or t-BP-GMA) and then it rapidly decreased with further increasing CP-GMA (or t-BP-GMA) content. Membranes prepared from TM-Bis-GMA or its mixtures exhibited better chlorine resistance than the membrane prepared from MPDA and TMC.