Compositional heterogeneity in partially hydrolysed poly(vinyl alcohol) byreversed phase liquid chromatography

Reversed phase high performance liquid chromatography (HPLC) was employed t o elucidate the composition distribution of partially hydrolysed samples of poly(vinyl alcohol) (PVOH), demonstrating that elution across a chromatogr am proceeded from higher to lower degree of hydrolysis (DoH). Fractions iso lated by preparative HPLC fractionation and characterised by H-1 nuclear ma gnetic resonance spectroscopy (NMR) were used as HPLC standards to construc t a calibration curve of retention time versus DoH, allowing for DoH determ ination of any PVOH sample once its chromatogram was available. Plots of cu mulative and differential distributions as a function of DoH were determine d, allowing for comparisons of samples having average DoH in the range 70-9 0 mol%. A second set of fractions originating from a parent polymer having different molar mass was also isolated to confirm that calibration was not influenced by molar mass or size exclusion effects. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.