A Mark-Houwink Equation for Polyvinyl Alcohol) from Sec-Viscometry

Abstract

A new Mark-Houwink equation for fully-hydrolyzed poly(viny! alcohol) has been determined using aqueous size exclusion chromatography (SEC) with on-line, differential viscometry detection. The Mark-Houwink K and a constants have been measured at 35° C over a wide range of molecular weights in an aqueous solution of sodium nitrate, a commonly used mobile phase for SEC-molecular weight characterization of polyvinyl alcohol). Absolute molecular weights determined using these Mark-Houwink values compare favorably among universal calibration. viscometry, and the Mark-Houwink (or intrinsic viscosity distribution) methods to those obtained from low-angle laser light scattering. The intrinsic viscosity distribution method is calibration independent and only requires a one time determination of the Mark-Houwink constants This new method for characterizing molecular weight of an unknown polyvinyl alcohol) is illustrated.