CHARACTERIZATION OF BINARY POLYMER MIXTURES BY SIZE-EXCLUSION CHROMATOGRAPHY WITH MULTIPLE DETECTION

We demonstrated that both components of binary polymer mixtures of polystyrene and poly(methyl methacrylate) can be characterized simultaneously by size exclusion chromatography equipped with multiple detectors. In this analysis scheme, the individual peaks of the two components are separated from the overlapped chromatogram by simultaneously solving the response signal intensities from two concentration detectors, i.e. a refractive-index detector and an ultra-violet/visible absorption detector. Then the absolute molecular-weight distribution of each component is obtained from the response of a light-scattering detector in conjunction with universal calibration. This method can be applied to binary mixture systems the two components of which have a distinguishable difference in refractive index as well as in absorptivity.