Hydrophilic poly(2-hydroxyethyl methacrylate)(PHEMA) and hydrophilic poly(acrylic acid)(PAA) interpenetrating polymer network (IPN) membranes were prepared by sequential polymerization method.
The PAA networks were prepared by polymerizing and crosslinking AA in the presence of precrosslinked PHEMA networks of varying Tg and hydrophilicity. Tg was varied by copolymerizing with buthyl acrylate (BA), methyl methacrylate (MMA) mixture and the hydrophilicity was controlled by varying the HEMA and BA/MMA ratio. The Tg of the membrane was measured by DSC.
The pervaporation of water-ethanol mixture was carried out and the permselectivity was investigated to evaluated the effect of the hydrophilicity and the Tg of the membrane. The swelling ratio and pervaporation rate increased with increasing hydrophilicity but showed no effect of Tg. The separation factor of water (in all ranges of feed concentrations, water permeated preferentially through these membranes) increased with Tg.
The hydrophilic-hydrophilic SIPN membrane was found to enhance the pervaporation rate and mechanical properties.