Synthesis of a cation-exchange fabric with sulfonate groups by radiation-induced graft copolymerization from binary monomer mixtures

Cation-exchange adsorbent based on a nonwoven polypropylene fabric carrying sulfonate functional groups was synthesized by a one-step graft copolymerization of sodium styrenesulfonate and acrylic acid monomers from binary monomer mixtures using the electron beam pre-irradiation method in air. The effect of various polymerization parameters (absorbed dose, reaction temperature and time, monomer ratio, Mohr's salt additive) on the degree of grafting was studied. It was found that the copolymerization process begins with the primary grafting of acrylic acid monomers on the nonwoven polypropylene fabric and continues by cografting of sodium styrenesulfonate and acrylic acid monomers. Total ion-exchange capacity and sulfonate group density were evaluated to vary within 3.5-5.5 and 1.0-2.16 mEq/g, correspondingly, for synthesized fabrics with a medium grafting degree (70-220%). These values are similar to those of sulfonated membranes obtained by radiation-induced graft polymerization of styrene with subsequent sulfonation of polystyrene chains. The main advantage of the studied approach is a one-step process of synthesis.