PHASE FLUCTUATION CHROMATOGRAPHY FOR LARGE-SCALE SEPARATION OF POLY(STYRENE-CO-ACRYLONITRILE) BY CHEMICAL-COMPOSITION

We propose phase fluctuation chromatography(PFC) to separate a large a mount of random copolymers into fractions with different chemical comp ositions. PFC is based on the tendency of a concentrated solution of t he copolymer to separate into different phases, each of which is enric hed with components of a specific composition. When the multiphase sol ution is injected into a column packed with porous materials that have specific moieties, domains rich in a component with greater affinity to (or less repulsion from) the surface will be retained longer than t he domains rich in the other component. Styrene-acrylonitrile copolyme rs with different acrylonitrile contents were used as model copolymers . The compositions of fractions obtained were determined from IR spect ra. A silanol or diphenyl surface retained styrene-rich components lon ger than the other components, whereas a cyano surface attracted acryl onitrile-rich components. The separation resolution was better when th e pore had a large surface area and selective surface moieties and whe n selective solvents and higher concentrations were used.