Surface characterization of polysaccharides, lignins, printing ink pigments, and ink fillers by inverse gas chromatography

Inverse gas chromatography (IGC) was used to determine the dispersive contribution to surface energy of three families of fibrous or powder-like materials: (i) polysaccharides; (ii) lignins from different sources; and (iii) printing ink pigments and ink fillers. The dispersive component of unpurified alpha hardwood cellulose was found to be close to 32 mJ . m(-2). This parameter increased substantially (up to 50%) when fibers were purified by acetone extraction or by corona treatment using a current discharge of 40 mA. The surface properties of other polysaccharides, namely starch, chitin, and two chitosans with different degrees of acetylated groups, were also investigated. Except for the soda-anthraquinone lignins, which showed the highest dispersive component of surface energy (115.6 mJ . m(-2)), other lignins, namely kraft, steam-explosion, and organosolv materials, showed very similar dispersive properties (45 to 49 mJ . m(-2)). As expected, lignosulfonates displayed a higher dispersive energy of about 67 mJ . m(-2). The study of printing ink pigments and ink fillers suggested that carbon black and calcium carbonate used for that purpose must have been subjected to a specific treatment in order to increase their surface energy. The dispersive component of the surface energy of other pigments, viz., red, yellow, blue, and white powders, was close to 40 mJ . m(-2). (C) 1996 Academic Press, Inc.