Nitrocellulose filled and natural rubber grafted poly(styrene-co-acrylonitrile) organophilic membranes for pervaporative recovery of aliphatic alcohols from water

Styrene (Sty) was copolymerized with acrylonitrile (AN) at varied molar ratios by emulsion polymerization in the presence of 1, 2.5, 5 and 7.5 wt% natural rubber (NR, 1,4-cis polyisoprene) latex and 0.5, 1, 1.5 and 2 wt% nitrocellulose (NC). During copolymerization the NC particles (~300–500 nm) were in-situ generated by controlled precipitation from AN monomer and thus it was incorporated into the NR grafted poly (Sty-co-AN) copolymer (noted as SAN) matrix. The organophilic membranes prepared from these grafted copolymers were characterized by FTIR, 13C NMR, XRD, DTA-TGA, mechanical properties, DMA, SEM, TEM and TEM-EDAX. These membranes were used for sorption and pervaporation of methanol–water, ethanol–water and isopropyl alcohol (IPA)-water binary mixtures. Three-level full factorial design-based optimisation showed a total flux (g/m2h)/ alcohol selectivity of 200.79/30.29, 211.92/35.83 and 216.49/42.43, respectively for 4 wt% aqueous methanol, ethanol and isopropyl alcohol (IPA), respectively in feed by the membrane prepared with an optimized composition of 4:1 Sty: AN molar ratio, 7 wt% NR latex and 2 wt% NC. The membrane was further used at varied feed concentrations and temperatures.