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Dielectric-barrier discharge treatment was used to modify fully bleached softwood kraft and unbleached softwood thermomechanical pulp handsheets. The effect of dielectric-barrier discharge treatment on the physical strength properties and dimensional stability of handsheets were analyzed. Increased dielectric-barrier discharge treatment power resulted in significant increases in the wet tensile index of handsheets. Increases in the surface acid content of pulp fibers do not appear to contribute to changes in paper properties, nor do changes to relative bonded area within handsheets. Enhanced wet strength via dielectric-barrier discharge treatment corresponds to increased dimensional stability. This appears to be due to fiber cross-linking in the case of bleached kraft pulp, since the wet-strain decreases as wet tensile and wet Young's modulus increase. In the case of unbleached thermomechanical pulp, the wet-strain shows no decrease, yet the wet Young's modulus increases as the wet tensile index increases.

This study investigates the fundamental topochemical effects of dielectric-barrier discharge treatment on bleached chemical pulp and unbleached mechanical pulp fiber surfaces. Fibers were treated with various levels of dielectric-barrier discharge treatment ranging from 0 to 9.27 kW/m 2 /min. Changes to the fiber surface topochemistry were investigated by atomic force microscopy (AFM). The AFM studies were complemented by inverse gas chromatography (IGC), contact angle evaluation, poly-electrolyte titration, viscosity testing and determination of water retention value (WRV). The static coefficient of friction and zero-span tensile index of sheets were also evaluated. Low dielectric-barrier discharge treatment levels resulted in increased surface energy and roughness. Fibers treated at high applied power levels showed surface energies and roughness levels near that of reference samples as well as evidence of degradation and decreased fiber swelling.Abbreviations: AFM -atomic force microscopy; BKP -bleached kraft pulp; IGC -inverse gas chromatography; TMP -thermomechanical pulp; WRV -water retention value.

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