Molecular Weight Distribution of Aspen Lignins from Conventional GPC, Universal Calibration, and Sedimentation Equilibrium

Molecular weight distributions of ball-milled, organosolv, alkali-extracted/mild acid-hydrolyzed and alkali-extracted/steam-exploded aspen lignins in tetrahydrofuran were compared using conventional gel permeation chromatography (GPC), universal calibration and sedimentation equilibrium. Molecular weight averages reported in the literature from universal calibration for the four low-molecular-weight lignins agreed more closely with values found in this study from sedimentation equilibrium experiments than from conventional GPC. This result supports the suggestion that these acetylated lignins fit universal calibration.