Abstract:SynopsisThe two-phase equilibrium in the system polystyrene (PS)-liquid sulfur dioxide [SOn(l)] was investigated, mainly at room temperature. The system consisted of an upper PS-rich phase, concentration (30-50)% depending on the way of preparation, and a lower phase containing less than 1% PS. The range of molecular weights of the PS samples used was 22,000-350,OOO (mW,). PS with an mu, value of 22,000 dissolved homogeneously in SOn(l). In systems forming two phases a fractionation of PS with respect to molec… Show more
The concentration and molecular weight distribution (GPC) of polystyrene (PS) in the two phases of the PS‐SO2 (δ)‐system were determined. Typical concentrations of PS in the upper phase were around 30%, while the lower phase contained at most 1% PS. An exception was a PS‐grade with a low molecular weight (MW 3.5 · 103), which dissolved homogeneously. The molecular weight of PS in the lower phase was substantially below an the one found in the concentrated phase. Mechanical agitation was necessary to attain an equilibrium state; during the equilibration the upper phase became more diluted. At the same time the molecular weight of the lower phase PS‐fraction increased, while the MW value in the upper phase remained practically unchanged and equal to that of the virgin sample. The fractionation with regard to the molecular weight between the two phases was also reflected in the Tg‐values of the fractions. The value of X(Flory‐Huggins parameter) determined from vapour pressure data above the concentrated phase was 0.8–1.
men wird. Fragen der Hydrodynamik und der Grenzflachenphanomene beim Stoffubergang sowie apparative Probleme beim Einspeisen der ProzeBstrome in die Hochdruckkolonne uber geeignete Verteilersysteme sowie auch die Niveaukontrolle beim Ausschleusen mussen in der weiteren Entwicklung dieses Verfahrens besonders beachtet werden. Daneben bietet die Verdusung rnit Stoffubergang und anschlieBender Phasentrennung als Mixer-Settler-Verfahren fur die Auftrennung von Fettgemischen interessante Moglichkeiten zur Weiterentwicklung.L i t e r a t u r
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