Characterizing the Average Composition and Molar Mass Distributions of a Poly(styrene-coacrylic acid) Copolymer by SEC-MALS-dRI-UV

This application note demonstrates how both the absolute molecular weight and composition of random-copolymer samples with a UV-absorbing component may be determined quickly and accurately, without a fraction collection step or NMR analysis. The technique utilizes size exclusion chromatography combined with analysis by three on-line detectors: multi-angle light scattering, differential refractive index and UV/Vis absorbance (SEC-UV-MALS-RI). Weight fractions of poly(styrene-co-acrylic acid) (PSAA) samples were analyzed using the tripledetector system and ASTRA^® software for macromolecular characterization. Results were found to be in good agreement with the reference values determined by 1H NMR spectroscopy.