Abstract

Acrylic acid (AA) and acrylonitrile (AN) were synthesized by solution polymerization with nanometer SiO₂. The copolymer solution was made into main body of the membranes, then composited with the polyvinyl alcohol (PVA) acetal membranes, to make the three-layer sandwich composite pervaporation membranes. The adsorption and the preferential sorption characteristics of the membranes were analyzed by studying swelling degree in different concentrations of methanol solution. Furthermore, the structure unit ratios of the P(AA-Co-AN/SiO₂) membranes were analyzed by X-ray Photoelectron Spectroscopy (XPS). Pervaporation experiments were carried out using these membranes to separate methanol/water mixture, and results showed that selectivity of the membranes has increased with increasing the ratio of AN, but ?ux decreased. When the comonomer ratio AA/AN was 1/1, for the 98wt% mixtures at 60?, the separate factor was up to 1534, and the permeation ?ux was 583 g/(m²·h). Moreover, the composite membranes also showed good stability by a long-term test of the pervaporation experiments.

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