Chemical composition characterization of blends formed by
styrene−acrylonitrile (SAN),
ethylene−propylenediene (EPDM) and EPDM-g-SAN copolymer
molecules has been performed
with size-exclusion chromatography with DRI and UV detectors. With
proper detector calibration
reliable average composition results were obtained, whereas it has been
found that the
composition distributions calculated from the chromatogram fractions
are affected by large
experimental errors. The blend components were successfully
separated with precipitation−redissolution liquid chromatography, and an evaporative light scattering
detector was found
suitable for eliminating baseline drifts in the chromatograms, due to
the eluent gradients which
had to be employed. The application of evaporative detectors for
quantitative measurements,
however, appears questionable.