| dc.contributor | Ramos, J., Wood, Pulp and Paper Res. Dept., University of Guadalajara, P.O. Box 52-93, 45020, Zapopan, Jalisco, Mexico; Sandoval, J., Wood, Pulp and Paper Res. Dept., University of Guadalajara, P.O. Box 52-93, 45020, Zapopan, Jalisco, Mexico; Davalos, F., Wood, Pulp and Paper Res. Dept., University of Guadalajara, P.O. Box 52-93, 45020, Zapopan, Jalisco, Mexico; Navarro, F., Wood, Pulp and Paper Res. Dept., University of Guadalajara, P.O. Box 52-93, 45020, Zapopan, Jalisco, Mexico; Rivera, J., Wood, Pulp and Paper Res. Dept., University of Guadalajara, P.O. Box 52-93, 45020, Zapopan, Jalisco, Mexico | |
| dc.description.abstract | Effect of soda and formaldehyde as pre-treatment chemicals during the chemimechanical pulping (CMP) of Populus deltoides have been studied. When the two chemicals are used in a mixture for cooking in one or two stages, the pulp has low strength properties, but when the chemicals are used in two separated stages the pulp become stronger although with lower brightness. For a same stage, increments in the formaldehyde quantities reduce the strength properties of the pulp but increase its brightness; increments in temperature seem not affect significatively the breaking length, but the tear index is increased notoriously and the brightness and the light scattering coefficient are reduced considerably. By using a 4% hydrogen peroxide in two bleaching steps, a final brightness of 67.7% is obtained. With the use of formaldehyde during the obtention of CMP from cottonwood, considerably thermal brightness stability is observed, but only a low light stability. | |
