Preparation Of Ion-exchange Membrane By SI-ATRP And Its Application

Ion-exchange membrane has an important application in purification of compounds.In recent years, surface-initiated atom transfer radical polymerization (SI-ATRP) technique attracts much attention in the surface chemical modification. Two new kinds of ion-exchange membranes were prepared by SI-ATRP, and their adsorptive properties were investigated.The regenerated cellulose membranes were modified by the reaction of the initiator, 2-bromoisobutyryl bromide with the hydroxyl groups on the surface of regenerated cellulose membrane to get the macroinitiator of the reaction surface-initiated atom transfer radical polymerization.Then poly(acrylonitrile)(PAN) and poly(tert-Butyl methacrylate)(PtMBA) were grafted on the surface of the membranes via surface-initiated atom transfer radical polymerization. Finally, the functionalized ion-exchange membranes were obtained via "click chemistry" -(3+2) azide -nitrile cycloaddition reaction and acid hydrolysis reaction, respectively. The structure of the modified membranes were characterized by X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR), elemental analysis and pore distributions measurement. The results showed that polyvinylterazole and poly(acrylic acid) had been successfully grafted on the surface of the cellulose membranes. Membranes surface morphology and structure were characterized by scanning electron microscopy (SEM) and we find that membranes pore size decrease gradually with increasing the polymerization time. Static adsorptive experiments confirmed that the bonding amount of polymer and adsorption capacity increase with the longer polymerization time in a certain range. And the maximum equilibrium adsorption capacities of lysozyme reached 475.6 mg/mL and 412.8 mg/mL. The results show that the obtained ion-exchange membranes have high adsorption capacities and some potential applications in the purification of biological samples.