Characterization of Hydroxy- Terminated Polybutadienes by Liquid Chromatography

Abstract

Size exclusion chromatography and liquid adsorption chromatography were used to characterise low- molecular weight hydroxy- terminated polybutadienes prepared by anionic polymerisation. Independent molecular weight distribution and functionality type distribution were obtained. Special chromatographic conditions denoted as critical point of adsorption were used in the determination of functionality type distribution. Under these conditions, the baseline recoveries between the peaks of separated fractions were observed for a broad range of molecular weights. Comparison of two different functionality averages was used to support both the suitability of the use of universal calibration in size exclusion chromatography and the expected absence of íunctionalities higher than two. The evaporative light-scattering detector was applied in liquid adsorption chromatography and the results were compared with measurements using differential refractive- index detector. Even if the quantitation of the chromatograms from evaporative light-scattering detector is difficult since the response factor depends on the sample molecular weight and on concentration . its application enables to utilise gradient elution chromatographic separation .The gradient elution can be used to determine higher functionalities in polybutadienes prepared by a free-radical process.