QUALITATIVE AND QUANTITATIVE-ANALYSIS OF STYRENE AND ITS VARIOUS OLIGOMERS BY LIQUID-CHROMATOGRAPHY

Two polystyrenes (crystal PS 1 and choc PS 2) were tested to determine the composition of low-molecular-mass products. The RP-HPLC method sh ows clearly, in both polystyrenes, two oligomeric entities: higher-mol ecular-mass (n>5) and lower-molecular-mass (n<5). The ratio between fr actions exhibits respectively the same value (1/4) in PS 1 and PS 2. H owever it is logical that the total oligomeric fraction in PS 1 was la rger than in PS 2. In addition, the styrene level in polystyrene cryst al determined by RP-HPLC coupled with gel permeation chromatography (G PC) was 2500 mg/kg. This technique exhibits a satisfactory recovery (7 9+/-5%). Styrene could not be determined in polystyrene choc. Automati on of combined GPC-RP-HPLC, in the future, will permit quantification of the lower styrene levels in commercial packaging polystyrene.