Produção de celulose kraft e papel de madeiras de Pinus taeda L. e Pinus patula Schltdl & Cham.

Abstract

Wood characteristics influence the yield of pulp processing and the quality of produced cellulose pulp and paper. Therefore, the goal of this study was to evaluate wood in different axial positions, measuring their proportions: adult and juvenile; earlywood and latewood, relating their influence on the chemical and physical properties and of Pinus taeda and Pinus patula woods on the production of unbleached kraft cellulose pulp and packaging papers. Three trees of each species were selected, with ages of 14 years, in which the commercial heights were divided in base, middle and top. The analysis of extractives, lignins, carbohydrates and ashes rates were done in accordance with the TAPPI standard. The physical and anatomical characteristics of wood that were analyzed were the basic density and proportion of adult/juvenile, earlywood/latewood, respectively. Afterwards, the woods were transformed in brown kraft cellulose pulp and then in papers, which were evaluated in regards to their physical and mechanical properties. The results of the chemical analysis, for both species, showed that wood from the top of the log presented less extractives, ashes and carbohydrates (cellulose and hemicellulose) rates, and a superior lignin rate compared to wood from the middle and base. Wood from the base of the logs resulted in higher density values than middle and top, in both species. The percentages of adult or latewood, for both species, were also higher than in base wood in comparison to top, which presented a higher percentage of young and earlywood. In the pulping process, wood with less lignin, higher carbohydrates rates and high density reached the higher yield and viscosity values, while, for produced papers, wood with higher tracheid lengths and viscosity values presented better results.