Characterization of the Reinforcement Potential of Different Softwood Kraft Fibers in Softwood/Hardwood Pulp Mixtures

Two morphologically different market kraft pulps, a New Zealand radiata pine medium grade and a benchmark northern hemisphere spruce pulp from interior British Columbia, were evaluated and compared for their reinforcement potential following supplementation at different levels to a Eucalyptus market kraft pulp. A full factorial experimental design including softwood pulps types, three levels of both wet-pressing and refining, and six different softwood proportions in softwood/eucalypt furnish mixtures (0, 5, 10, 15, 20, and 100%), was employed to generate two independent regression models using SAS General Linear Model procedure, from data obtained from handsheet evaluation. It was conclusively shown, with statistical significance, that the reinforcement potential of softwood market kraft pulps in softwood/hardwood mixtures can readily be characterized and predicted through the measurement of fracture energy index of handsheets made from 100% softwood fiber