Marília da Silva Bertolini

Accelerated artificial aging of particleboards from residues of CCB treated Pinus sp. and castor oil resin

Tests simulating exposure to severe weather conditions have been relevant in seeking new applications for particleboard. This study aimed to produce particleboards with residues of CCB (chromium-copper-boron oxides) impregnated Pinus sp. and castor oil-based polyurethane resin, and to evaluate their performance before and after artificial accelerated aging. Panels were produced with different particle mass, resin content and pressing time, resulting eight treatments. Particles moisture and size distribution were determined, beyond panel physical and mechanical properties, according to NBR14810-3: 2006. After characterization, treatments B and G (small adhesive consumption and better mechanical performance, respectively) were chosen to artificial aging tests. Statistical results analysis showed best performances were achieved for waterproof aged samples, of both B and G treatments. As example, in treatment B, MOR and MOE values were 23 MPa and 2,297 MPa, samples before exposure; 26 MPa and 3,185 MPa, 32 MPa and 3,982 MPa for samples after exposure (non-sealed and sealed), respectively.

Restoration of Structural Timber Elements Using Epoxy Resin: Analysis of Mechanical Properties

Brazil cultural heritage is composed by numerous constructions that describe the various historical periods lived by country. Constructions arent in good conservation status, showing systematically some deterioration level of their structural elements, among them those of wood. Restoration process aims to preserve the identity of original cultural heritage. It is essential maintain structural characteristics related to mechanical loads response which are closely dependent on wood properties avoiding possible structural shocks. Wood deterioration can be characterized by fungi decay or termite attack. Depending on level and position of the deteriorated area in structural set, local interventions are enough to maintain structural integrity. Polymeric resins are material options that can be used when removed these deteriorated regions, requiring compatibility with wood to maintain structural elements properties. This paper aims use of a technical for restoring structural timber from historic buildings, based on removal of decayed regions and filling them with epoxy resin. To analyze restoration effectiveness, properties in static bending, according to Brazilian standard, were determined. Samples were produced containing one and three restorations along the specimens (105 cm in length and nominal square cross section of 4.5 cm side), on the same side. Samples of Pinus taeda with gaps generated in the specimens with dimensions of 1.10 cm in depth and 8 cm in length were tested, with restorations placed in central region. For grafting of these gaps bicomponent epoxy resin was employed, prepared by mixing components in 1:1.5 proportions. Resin was injected into splices and its cure occurred in a seven days period, using methodology restoration to simulate a situation in which these structural elements have been used. Samples were requested in static bending to obtaining the product of inertia, analyzing the amendment under the aspect of tractioned and as well under compressed edge. It is observed the viability of restoration using filling epoxy resin in timber samples, considering the mechanical performance and practicality of the methodology for local keeping.

Painéis de partículas provenientes de rejeitos de Pinus sp. tratado com preservante cca e resina derivada de biomassa

RESUMO – A utilizacao do preservante CCA (sais de cromo, cobre e arsenio) tem sido questionada devido ao impacto relacionado a dispersao, principalmente, do cobre e do arsenio para o ambiente, antes de sua completa fixacao na madeira. Outra questao se relaciona a disposicao indevida dos residuos provenientes da madeira tratada, viabilizando a lixiviacao devido a maior area passivel desses rejeitos sujeita a tal fenomeno. Este trabalho teve como objetivo a producao de paineis de particulas, avaliando o efeito da adicao de residuos de Pinus sp. tratado com sais de cromo, cobre e arsenio (CCA), em associacao com material da mesma especie sem preservantes, alem de alteracoes no teor de adesivo poliuretano a base de mamona empregado na producao. As propriedades dos paineis produzidos foram determinadas conforme recomendacoes da NBR 14810-3: 2006. Por meio de analise estatistica, observou-se que a adicao da madeira tratada proporcionou desempenho superior no inchamento em espessura (2 h), ao passo que esse insumo utilizado na mesma proporcao que a madeira sem preservantes foi significante, obtendo os melhores resultados na adesao interna. Os modulos de ruptura e de elasticidade na flexao nao sofreram influencia das variacoes nos insumos utilizados nos paineis. Os paineis, em grande parte, apresentaram-se em conformidade com os principais requisitos nesse âmbito, mostrando a possibilidade da utilizacao dos referidos insumos na producao, alem da obtencao de um produto com consideravel apelo ambiental. Palavras-chave: Pinus sp.; Paineis aglomerados; Tratamento CCA. PARTICLEBOARDS USING WASTES FROM CCA-TREATED Pinus sp. AND RESIN FROM BIOMASS

Influence of growth ring orientation of some wood species to obtain toughness

Wood toughness is a mechanical property of interest in structural design where the load impact must be considered, finding a strong application in bridges, however, not an integral part of the mechanical properties commonly investigated in the characterization of this material. This study aimed to investigate with the aid of variance analysis, the influence of growth ring orientation to obtain toughness for Angelim Saia (Parkia pendula), Eucalyptus grandis, Pinus elliottii and Corymbia citriodora wood species, considering three different positions, so that the orientation causes tensile strength in fibers near the pitch, near the bark, and in the radial direction. The results of the statistical analysis revealed that there was no significance in the orientation of the growth rings to obtain the toughness of the wood species investigated, where the highest values were for Corymbia citriodora and the least values were for Pinus elliottii.

Thermal Insulation Particleboards Made with Wastes from Wood and Tire Rubber

The concept of sustainable buildings addresses the environmentally efficiency, with respect to energy consumption, by adopting products that offer thermal insulation. Moreover, use of wastes from different materials also contributes to obtain products for this application. The volume of wastes from timber industry and those from tires are an environmental problem. This study aimed to production and characterization of particleboards using wastes from wood and tire rubber with castor-oil polyurethane resin. Panels were produced containing only wood and also with addition of tire rubber. The properties determined were density, modulus of rupture (MOR) and modulus of elasticity (MOE) in bending, according to Brazilian Code NBR 14810-3 (2006), and thermal conductivity. Statistical analysis was conducted in physical and mechanical properties. Panels containing wood were classified as low density (0.55 g/cm³), while those with wood and tire rubber resulted in medium density (0.78 g/cm³). For mechanical properties, the addition of rubber resulted in increased of MOR and reduction for MOE. Superior performance for thermal conductivity was achieved for panels produced only with wood. However, samples with a mixture of wood and tire rubber also showed consistent thermal conductivity with similar products. Considering the results obtained, panels containing wood and tire rubber addition have potential for application as thermal insulation.

Painéis OSB fabricados com madeiras da caatinga do nordeste do Brasil

Este trabalho objetivou avaliar a viabilidade da producao de paineis OSB feitos com especies de madeira da caatinga do nordeste do Brasil – marmeleiro (Croton sonderianus Muell. Arg.), jurema-branca (Piptadenia stipulacea (Benth.) Ducke) e catanduva (Piptadenia moniliformis Benth.) – e resina poliuretana bicomponente derivada de mamona. As propriedades investigadas foram: densidade aparente; inchamento em espessura e absorcao de agua, ambos em 2 h e 24 h; modulo de elasticidade e resistencia na flexao, na direcao paralela e na direcao perpendicular ao painel; adesao interna e arrancamento de parafuso em relacao a face, conforme as normas europeias EN. Os resultados das propriedades fisicas e mecânicas obtidas evidenciaram a possibilidade da producao em laboratorio de paineis OSB com as tres especies analisadas, conforme valores medios e variabilidade de propriedades equivalentes as chapas fabricadas em escala industrial, alem de comparados aos requisitos da norma EN 300 (EUROPEAN..., 2006) para paineis dos tipos OSB/3 e OSB/4. Pela analise de variância, os paineis OSB fabricados com strands de madeiras de catanduva apresentaram os melhores resultados para as propriedades mecânicas; para as fisicas, os melhores desempenhos foram provenientes dos paineis feitos com madeira de marmeleiro e jurema-branca.

Influência do teor de umidade na propriedade de tenacidade de espécies florestais

Wood toughness is a mechanical property of interest in structural design where load impact must be considered, as in the construction of silos, bridges and formwork for reinforced concrete structures. However, toughness is not an integral part of the mechanical properties commonly investigated in the characterization of this material. This study aimed to investigate, with the aid of analysis of variance and Charpy pendulum test, the influence of moisture content (30; 20; 12; 6; 0%) to obtain the toughness of angelim saia (Vatairea sp), Eucalyptus grandis, Pinus elliottii and Corimbia citriodora wood species, considering the orientation of growth rings in relation to the direction of impact load. Statistical analysis carried out using ANOVA and Tukey test revealed significant influence of moisture content on toughness only with respect to angelim saia wood. Statistical analysis also showed equivalent results for the other three species, that is, moisture content did not significantly influence toughness. Thus, we conclude that moisture content may be significant in obtaining toughness according to the wood species analyzed and higher moisture content can provide higher values of toughness.

Influência do Teor de Umidade na Propriedade de Tenacidade de Espécies Florestais / Influence of the Moisture Content of Some Wood Species on Toughness

Wood toughness is a mechanical property of interest in structural design where load impact must be considered, as in the construction of silos, bridges and formwork for reinforced concrete structures. However, toughness is not an integral part of the mechanical properties commonly investigated in the characterization of this material. This study aimed to investigate, with the aid of analysis of variance and Charpy pendulum test, the influence of moisture content (30; 20; 12; 6; 0%) to obtain the toughness of angelim saia (Vatairea sp), Eucalyptus grandis, Pinus elliottii and Corimbia citriodora wood species, considering the orientation of growth rings in relation to the direction of impact load. Statistical analysis carried out using ANOVA and Tukey test revealed significant influence of moisture content on toughness only with respect to angelim saia wood. Statistical analysis also showed equivalent results for the other three species, that is, moisture content did not significantly influence toughness. Thus, we conclude that moisture content may be significant in obtaining toughness according to the wood species analyzed and higher moisture content can provide higher values of toughness.

Pinus caribaea var. hondurensis Wood Impregnated with Methyl Methacrylate

AbstractThis paper investigates the normal hardness, the compressive strength, and the modulus (parallel to the grain) of Pinus caribaea var. hondurensis wood in pristine condition and impregnated ...