Inclusion of cellulose pulping waste for production of medium density particleboards

Abstract

The pulp production process generates several residues, among them, the material resulting from the purification known as UKP (Unbleached Kraft Pulp). The use of waste in the manufacture of products can add value and solve environmental problems, as well as contributing to the development of new technologies. The objective of this work was to evaluate the potential of using UKP (Unbleached Kraft Pulp) and wood of Eucalyptus sp. for the production of MDP panels. The treatments consisted of different percentages of particles of the residue in mixture with particles of Eucalyptus sp. (25%, 50%, 75% and 100% of UKP), and 100% of the eucalyptus particles (control). The panels were made with nominal density of 0.70 g / cm3; face / core / face ratio of 20:60:20; 12% urea-formaldehyde adhesive for the faces and core. The pressing cycle consisted of a dose of 3.92 MPa, a temperature of 160 ° C and a time of 8 minutes. The following tests were performed: water absorption after 2 and 24 h of immersion, swelling in thickness after 2 and 24 h of immersion, apparent density, and non-return rate in thickness, humidity, perpendicular traction and static bending. The values for the physical properties of water absorption and thickness swelling after 24 h ranged from 53 to 130% and from 8 to 50%, respectively, according to the increase of the waste amount in the panels composition. Similarly, there was a decrease in MOE values (from 2264.82 to 543.72 Mpa) and MOR (from 19.66 to 3.46 Mpa). It is recommend to use 35% replacement of wood particles by UKP waste particles for the production of MDP panels, thus allowing a waste disposal in the generation of new products, while maintaining the physical and mechanical properties within the required values standards.