Abstract: Particleboard can be produced from a mixture of different lignocellulosic materials, which can be chosen depending on the density required for the panel and its applications. The aim of this study was to evaluate the mechanical properties of particleboard with bamboo, pine and mate for a new product of high density for the special applications currently served by HDF. Particles of bamboo (Phyllostachys aurea) finely chopped sticks of mate (Ilex paraguariensis) and commercial particles of southern pine (Pinus taeda) wood were used. These particles used 100 % by weight in the panel or in mixtures of 50 % each (three mixtures) or in a triple mixture of one third each, were glued in a drum-type rotary mixer with melamine-urea-formaldehyde (MUF) resin, and pressed in hydraulic press at 120 °C and 5,88 MPa for 10 minutes, up to 6 mm thickness. The panels were produced with 900 kg/m3 nominal density and, after pressing, were conditioned at 20 ºC and 65 % relative humidity. Statistical was performed by means the variance analysis and simplex centroid experimental design, with three replicates. It was found the use of pine particles contributed mainly to increase the panel's strength and stiffness, while the use of mate particles facilitated internal bond strength. The mixtures modeling showed that the water absorption, the strength and stiffness in bending and the internal bond strength are explained by the cubic model, while the thickness swelling and hardness are explained by the quadratic model. The best physical and mechanical properties results were found for the pine, bamboo and mate same ratio mixture.

ABSTRACT Were characterized microstructurally and mechanically the Ti-6Aℓ-4V alloy obtained through powder metallurgy in an uncontrolled atmosphere, varying the sintering parameters, arose. The samples were compacted in a uniaxial press at 874 MPa, 999 MPa, and 1124 MPa, and sintered without a protective atmosphere or vacuum, at 675 °C, 750 °C, and 850 °C. When sintering the material, the oxides influenced the results due to titanium’s high affinity for interstitial elements, promoting increased density and high hardness values. Based on the results, the treatment carried out at a pressure of 1124 MPa and a temperature of 750 °C showed the highest hardness in the beta phase (β), with a value of 1165.1 HV. In the alpha phase (α), the highest value was 1321.3 HV, presented by the treatment performed at a pressure of 999 MPa and a temperature of 850 °C. The high hardness values observed in the alloy are associated with the reinforcement promoted by the dissolution of Fe atoms. Materials with high hardness values use in the aerospace and biomedical industries, which always look for better mechanical resistance results, thus increasing their products’ useful life and applicability.

RESUMO Foram caracterizadas micro estruturalmente e mecanicamente a liga Ti-6Aℓ-4V obtida através da metalurgia do pó em atmosfera não controlada variando os parâmetros de sinterização. As amostras foram compactadas em uma prensa uniaxial à 874 MPa, 999 MPa e 1124 MPa, e sinterizadas sem atmosfera protetora ou vácuo, nas temperaturas de 675 °C, 750 °C e 850 °C. Ao sinterizar o material, houve influência dos óxidos nos resultados devido à alta afinidade que o titânio tem por elementos intersticiais, promovendo um aumento na densidade e elevados valores de dureza. A partir dos resultados verificou-se que o tratamento realizado na pressão de 1124 MPa e temperatura de 750 °C foi o que apontou a maior dureza na fase beta (β), sendo o valor de 1165,1 HV. Na fase alfa (α), o maior valor foi de 1321,3 HV, apresentado pelo tratamento realizado na pressão de 999 MPa e temperatura de 850 °C. Os elevados valores na dureza observados na liga estão associados ao reforço promovido pela dissolução átomos de Fe. Materiais com elevada dureza possuem uma vasta aplicação nas indústrias aeroespaciais e biomédicas, que buscam sempre por melhores resultados de resistência mecânica, aumentando assim a vida útil e a aplicabilidades de seus produtos.

RESUMO Os bambus são plantas que apresentam rápido crescimento, com excelentes propriedades físico-mecânicas, as quais derivam, principalmente, das características e dimensões de seu principal elemento estrutural: suas fibras. Objetivou-se realizar a descrição dimensional (comprimento, largura, diâmetro do lume e espessura da parede) e caracterizar os índices e coeficientes técnicos das fibras de espécies de bambu que ocorrem no Brasil, por meio de levantamento bibliográfico. Os resultados mostraram que a densidade básica em corpos de prova de hastes das espécies levantadas variou entre 0,451 g cm-3 e 0,780 g cm-3, evidenciando grande variabilidade entre elas. Os valores médios observados para as dimensões das fibras foram 2,29 mm de comprimento, 16,4 µm para largura total, 6,4 µm de espessura da parede e 3,5 µm para o diâmetro do lume. A partir destes dados, foram estabelecidos índices e coeficientes técnicos que sustentam boas propriedades físico-mecânicas do bambu nas várias espécies estudadas.

ABSTRACT Bamboos are fast-growing plants, with outstanding physical-mechanical characteristics that may be chiefly ascribed to the features and dimensions of their main structural element: their fibers. This study aimed to perform a dimensional description (length, width, lumen diameter and wall thickness) and depict the indices and technical coefficients of fibers of bamboo species that occur in Brazil, through a bibliographical survey. The results showed that the basic density in test stem-specimens of the surveyed species varied between 0.451 g cm-3 and 0.780 g cm-3, what revealed a great variability among them. The average values observed for the fiber dimensions were 2.29 mm for length, 16.4 µm for total width, 6.4 µm for wall thickness and 3.5 µm for lumen diameter. From these data, it was possible to estimate indices and technical coefficients that support good physical-mechanical characteristics of bamboo in the several studied species.

RESUMO O bambu é um material utilizado em escala global em diversas áreas. Contudo, necessita de aprimoramento nos processos para utilização industrial, no Brasil. A produção de painéis laminados colados está em crescimento no mundo e pode ser uma fonte de recursos para esse fim. Objetivou-se avaliar as propriedades físico-mecânicas de painéis laminados de bambu produzidos com duas espécies (Phyllostachys aurea e Dendrocalamus asper) e dois processos produtivos/adesivos (laminado colado e termomecânico). Para as análises mecânicas, corpos de prova retirados dos painéis foram submetidos a ensaios de cisalhamento, dureza Janka e flexão estática. Os mesmos corpos foram utilizados para a determinação da massa específica aparente, teor de umidade e grau de compressão. A massa específica aparente variou entre 0,75 g cm-3 e 0,79 g cm-3, com teor de umidade de equilíbrio entre 7,83 % e 10,42 %. Os maiores valores das propriedades mecânicas foram verificados no bambu laminado termomecânico. Para D. asper, o módulo de ruptura foi de 146,8 MPa, a resistência ao cisalhamento na linha de cola de 6,36 MPa e a dureza Janka atingiu 3.852 N, enquanto, para P. aurea, constatou-se 19.603 MPa no valor do módulo de elasticidade. Concluiu-se que a produção de painéis laminados de bambu, em especial no processo termomecânico, é uma potencial alternativa.

ABSTRACT Bamboo is a material used on a global scale in several areas. However, it needs adaptation in the processes for industrial use, in Brazil. The production of glued laminated panels has been growing in the world and this material can be a source of resources for this purpose. This study aimed to evaluate the physical-mechanical properties of laminated bamboo panels produced with two species (Phyllostachys aurea and Dendrocalamus asper) and two production processes/adhesives (glued-laminated bamboo and thermo-mechanical laminated bamboo). For the mechanical properties analysis, specimens removed from the panels were subjected to shear tests, Janka hardness and static bending. The same specimens were used to determine the apparent density, moisture content and degree of compression. The apparent density varied between 0.75 g cm-3 and 0.79 g cm-3, with equilibrium moisture contents between 7.83 % and 10.42 %. The highest values for the mechanical properties were verified in the thermo-mechanical laminated process. For D. asper, the modulus of rupture was 146.8 MPa, the shear glued line 6.36 MPa and the Janka hardness 3,852 N, while, for P. aurea, the modulus of elasticity reached 19,603 MPa. It was concluded that the production of bamboo laminated panels, especially using the thermo-mechanical process, can be a potential alternative.