Adsorption of water vapor on modified methacrylate polymeric sorbents

Adsorption of water vapor on methacrylate copolymers and terpolymers was studied. An increase in the content of the cross-linking agent gives rise to increase in the limiting adsorption of water vapor at the saturation pressure (a(s)) and to decrease in the concentration of primary adsorption centers. Modification of the initial copolymer containing 60 % of 2,3-epoxypropyl methacrylate (EPMA) monomer and 40 % of cross-linking agent, ethylene dimethacrylate, with diethylenetriamine (DETA) results in an increase in the a(s) value, while modification with C-12 and C-18 alkyl benzyl, and phenyl groups gives rise to decrease in the a(s) values for the copolymeric sorbents. The concentration of primary adsorption centers (a(m)) increases considerably on modification of the copolymer with DETA and C-12 groups and decreases markedly on modification with benzyl and phenyl groups. For terpolymers, containing EPMA and styrene, an increase in the styrene/EPMA ratio reduces the a(s) and a(m) values. The copolymer modified with DETA groups possesses the most hydrophilic properties, while the copolymer modified with benzyl group exhibits the most hydrophobic properties. The mechanism of adsorption of water molecules on the polymers is discussed.