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

Abstract

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.