Characterization of the surface of cellulosic fibers using aqueous two-phase partitioning

Abstract

The physical chemical surface properties of cellulosic fibers have been assessed using aqueous two-phase partitioning in polyethyleneglycol (PEG) — dextran systems containing hydrophobic palmitoyl-PEG and positively charged trimethylamino-PEG. The sizing with alkylketenedimer (AKD) of bleached kraft pulp could easily be monitored with this new technique. The adsorption of oleate on thermomechanical pulp could also be followed. In this case the oleate adsorbs preferentially on the hydrophobic parts of the fibers making them more hydrophilic. We also investigated bleached sulphite fibers treated in various ways. Ethanol extraction made the fibers more hydrophilic, obviously by removing resinous material from the fiber surfaces. Heat treatment of the fibers made the fibers more hydrophobic. The resinous material probably melts and covers a larger part of the fiber surface.