Molar mass distributions in homopolymer blends from multimodal chromatograms obtained by Sec/Gpc with a concentration detector

LUIS ALBERTO CLEMENTI; GREGORIO RAÚL MEIRA; DUSAN BEREK; LUDMILA IRENE RONCO; JORGE RUBÉN VEGA

POLYMER TESTING

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2015 vol. 43 p. 58 - 67

0142-9418

This article proposes data treatment for estimating the individual (and unimodal) molarmass distributions (MMDs) of each polymer component in a blend from multimodalconcentration chromatograms obtained by size exclusion chromatography (SEC/GPC). TheDifferential Refractometer (DR) chromatograms are deconvoluted into linear combinationsof exponentially-modified Gaussian distributions. The deconvolutions are possible if theindividual peaks are not fully overlapped and if the mass fractions of the minor componentsare not too low. To help determine the number and approximate location of theindividual peaks, the second derivative of the chromatogram is employed. For blends ofchemically identical homopolymers, the deconvolution stage directly provides the massfractions of the individual peaks. For blends of two chemically different homopolymers,the chemical composition and detector responses of the individual components must bedetermined, for example with the help of dual detection (UV/DR). The procedure wasvalidated with blends of a priori known components.