The growth of the civil construction sector, made necessary to develop alternative products made of sustainable materials. Within this context came the cross laminated timber panels (CLT), which are formed by gluing veneer arranged at 90°, which provide high strength and great versatility, as constructive elements. This research aimed to evaluate the chemical properties of the particles of both materials and evaluate the performance of CLT panels made with Pinus oocarpa and waste wood from Coffea arabica. The panels were made with three orthogonal layers with veneer of pine and coffee wood, using the phenol-formaldehyde (PF) adhesive with a spread rate of 0.35kgm-² and the hydraulic press with a pressure of 1,2×107 N.m-2for 15 min. The physical, mechanical properties, acoustic and thermal performance of the panels were evaluated. There was a significant difference for water absorption in 2 and 24 hours. The panels produced only with coffee wood waste showed the lowest water absorption rates, corresponding to 10.2 and 33.3%, in 2 and 24 hours. In relation to the MOE, the panels made with varied veneer were statistically equivalent to each other and the panels made of pine blades showed a MOE corresponding to 3,33×107 N.m-2. The same trend was observed for MOR, since the average value obtained for pine panels, corresponding to 1,35x108 N.m-2 was significantly higher. Panels made of coffee veneer and pine veneer showed no delamination. With regard to acoustic and thermal evaluation, all panels met the minimum requirements indicated in the standards, with emphasis on coffee wood waste, associated or not with pine wood.Key words: Adhesive; Coffee; Chemical analysis; Hybrid panel; Technological properties.
25 February 2023 in Clean Technologies and Environmental Policy
This study aimed to use the petiole residues of miriti to partially replace pine wood and evaluate the effects of this incorporation on the physical and mechanical properties of the particleboards. Panels were produced with 0, 25, 50, and 75% of miriti in partial replacement of wood and 12% of urea-formaldehyde adhesive. The chemical-physical properties of miriti residues showed potential particleboard production as they were similar to those of pinewood. For the physical properties, the panels were classified as low density. There was an increase in the compression ratio and, consequently, in the hygroscopicity . For the mechanical properties, it was observed that the modulus of elasticity (MOE) and modulus of rupture (MOR) did not show any statistical differences. For perpendicular traction (PT), there was a significant reduction in 50%. Considering a general analysis of the physical and mechanical properties, up to 40% of mirti can be substituted, as in this situation they meet the properties mentioned in CS-236-66, except for PT for commercialization of the panels.
6 February 2022 in Research, Society and Development
Os oriented strand board (OSB) são um importante produto de madeira projetado, fabricado através da colagem de partículas strand em camadas cruzadas, sendo amplamente aplicado em construções, embalagens, decks, pisos, revestimentos de paredes e até mesmo para fins de suporte de carga. Para a produção destes painéis, podemos utilizar de biomassa da agricultura, como resíduos da atividade cafeeira. O objetivo desta pesquisa foi avaliar a composição química da madeira de café e do pinus, bem como as propriedades físicas e mecânicas dos painéis produzidos com a substituição do pinus pelo resíduo. Os painéis OSB produzidos, utilizaram a substituição do pinus pela madeira de café em 0 (T1), 25 (T2), 50 (T3), 75 (T4) e 100% (T5). Os resultados mostram que houve melhorias significativas nas propriedades físico-mecânicas e que os tratamentos atenderam o mínimo exigido por norma, com exceção do T2. Evidencia-se, portanto, o potencial de utilização do resíduo da madeira de café para a produção de painéis OSB, uma vez que este bioproduto que evitará a destinação incorreta do resíduo e vários outros problemas ambientais.
Coffee is one of the most consumed commodities globally, and its harvests generate large quantities of wood waste with low industrial value. This study aimed to explore the potential of residual Coffea arabica wood to produce lignocellulose microfibrils and lignocellulose nanofibrils (LCMF/LCNF) and biodegradable films with possible application in packaging. The fibers were treated with 5% NaOH and fibrillated in an ultrarefiner until they formed a gel. The resulting suspensions were used to create films whose physical, morphological, optical, and mechanical properties were analyzed. The NaOH treatment removed extractives and exposed hemicelluloses, allowing the gel point to be reached with just seven passes through the ultrarefiner, saving energy (~4700 kWh/t). More than 65% of the fibers had diameters of less than 100 nm and little sedimentation after 8 h. The films were flexible, thin (24.5 µm), with a high density (~1100 kg/m3) and good resistance to grease, as well as a water vapor permeability of ~1230 g/m2/day, suitable for packaging bread, fruit, and vegetables. However, the higher wettability of the surface may limit its use in humid environments. The films showed moderate tensile strength (~25 MPa) but low puncture resistance (~7 N mm), making them suitable for biodegradable packaging.
29 November 2021 in Revista Brasileira de Engenharia de Biossistemas
O objetivo desta pesquisa foi avaliar o reforço de fibras de bambu em compósitos poliméricos. Para tanto, o bambu da espécie (DENDROCALAMUS STRICTUS) foi processado em moinho de martelos e peneirado. Após a caracterização "in natura", os corpos de prova foram conformados em prensa a partir de dois tratamentos, 100% polipropileno e 80% polipropileno / 20% fibras de bambu, e testados mecanicamente por dobra em máquina de ensaio universal. Os resultados da caracterização das fibras indicaram propriedades químicas compatíveis com os valores publicados na literatura, além de resultados de densidade consideravelmente superiores. Por outro lado, os valores do módulo de elasticidade e de ruptura decorrentes dos ensaios mecânicos dos compósitos não apresentaram diferenças estatísticas entre os tratamentos analisados.