Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Orman Endüstri Mühendisliği Anabilim Dalı, 2007. / Bibliyografya var.

Made available in DSpace on 2014-06-11T19:27:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-21Bitstream added on 2014-06-13T19:14:25Z : No. of bitstreams: 1 ferreira_bs_me_guara.pdf: 1757485 bytes, checksum: 644373e17c086aa6bd2de1a3a27e1610 (MD5) / Estudos relacionados a matérias-primas alternativas para a substituição parcial ou total de madeira na produção de produtos engenheirados, mais especificamente de painéis, vem sendo desenvolvidos com a finalidade de diminuir a utilização da madeira e também aproveitar resíduos, que muitas vezes não possuem valor agregado. Por este motivo este trabalho teve o intuito de caracterizar a utilização da casca de noz macadâmia na produção de painéis de partículas, tendo em vista que esta casca é um resíduo com alta resistência, porém raramente possui utilização. Para tanto se testou quatro composições de painéis de partículas, com 0%, 30%, 60% e 100% de casca de noz macadâmia com base na massa de partículas. Avaliou-se a razão de esbeltez das partículas e as propriedades físico-mecânicas dos painéis com base na norma brasileira ABNT NBR 14810-3 (2006). Foram realizados os ensaios físicos de densidade, teor de umidade, inchamento em espessura durante 2 e 24 horas e absorção de água durante 2 e 24 horas. Os ensaios mecânicos realizados foram de flexão estática, para a determinação do módulo de ruptura (MOR) e do módulo de elasticidade (MOE), e o de tração perpendicular à superfície também conhecido como adesão interna. Com os resultados obtidos notou-se que com a adição de casca de noz macadâmia ocorreu diminuição da resistência mecânica, tanto com relação a adesão interna quanto com relação ao MOR e MOE, sendo que este último diminuiu abruptamente com a adição de apenas 30%; e maior instabilidade dimensional, pois ocorreu o aumento do inchamento em espessura e da absorção de água. Este resultado foi devido principalmente à geometria das partículas de macadâmia que não permitiu uma boa interação entre o substrato e o adesivo. Destaca-se ainda que a alta densidade da casca de noz macadâmia dificultou a interação... / Studies related to alternative raw materials for the partial or total substitution of wood in the production of engineered products, specifically panels, has been developed with the aim of reducing the use of wood and also recycle waste that often have no value. For this reason this study aimed to characterize the use of macadamia nutshell in the production of particleboard, given that this bark is a residue with high strength, but rarely has use. For that four different compositions of particle boards with 0%, 30%, 60% and 100% of macadamia nutshell based on the mass of particles were tested. The slenderness ratio of the particles and the physical-mechanical properties of panels were evaluated based on the Brazilian standard ABNT NBR 14810-3 (2006). The physical tests performed were density, moisture content, thickness swelling for 2 hours and 24 hours and the water absorption during 2 hours and 24 hours. The mechanical tests performed were the static bending, for determining the modulus of rupture (MOR) and modulus of elasticity (MOE) and the tension perpendicular to surface also known as internal bonding. With the results obtained it was noted that with the addition of Macadamia nutshell there was a decrease in mechanical strength, with respect to internal bonding and MOR and MOE, which latter abruptly decreased with the addition of only 30%; and in the dimensional stability, because occurred the increasing of the thickness swelling and water absorption. This result was mainly due to the macadamia particles geometry, which did not allow a good interaction between the substrate and the adhesive. Note also that the high density of the macadamia nutshell hindered the interaction between particles, because it blocked a sufficient panel compression

The effects of initial particle moisture content, wood-cement ratio and density on physical (thickness swelling and water absorption) and mechanical properties (MOE, MOR, IB and edgewise compression) were investigated. Five initial particle moisture content levels - 0-6%, 8-15%, 25-30%, 40-50% and 60-80%; three wood-cement ratios - 1:1, 1:1.5 and 1:2; and three density levels at each wood-cement ratio - 1:1 -0.472 g/cm³, 0.528 g/cm³ and 0.622 g/cm³, 1:1.5 - 0.636 g/cm³, 0.707 g/cm³ and 0.809 g/cm³; and 1:2 - 0.763 g/cm³, 0.847 g/cm³ and 0.939 g/cm³ were used. Combinations of the above variables gave 45 treatments. Three replicate boards were made for each treatment thus giving a total of 135 panels for the study. A total of 135 test specimens were used for each property tested. Results from the tests were compared to the German and ISO Standards for similar boards and to the Canadian Waferboard Standard. Initial particle moisture content was highly significant in the development of physical and mechanical properties of magnesite cement-bonded particleboard. Increasing initial particle moisture content from 0-6% to 60-80% resulted in the reduction of the physical and mechanical properties of the boards. The highest initial particle moisture content of (60-80%) yielded the lowest physical and mechanical properties. For manufacture of boards of favourable mechanical properties, an initial particle moisture content of not more than 15% is recommended. On the other hand, a higher initial particle moisture content (>40%) is considered desirable if board thickness and water absorption are to be minimized. All the mechanical properties tested consistently increased by increasing wood-cement ratio and density and were highest at 1:2 wood-cement ratio and density level 3 of each wood-cement ratio. Thickness swelling and water absorption were consistently reduced by increasing wood-cement ratio and density. In both physical properties tests, the 1:2 wood-cement ratio and density level 3 yielded the lowest values. Thirty-two of the forty-five treatment combinations of initial particle moisture content, density and wood-cement ratio pass the MOE requirement of the German Standard DIN 52 362 for Portland cement-bonded particleboard; forty-one treatments met the minimum MOE Canadian Waferboard Standard requirements, while no treatment meet the MOR requirements for this Standard. Eleven of the forty-five treatments met the minimum IB Canadian Waferboard Standard requirements. All the 45 treatments pass the ISO building board requirements in thickness swelling, while 18 treatments pass the water absorption requirements for this Standard. Most of the treatment combinations compare favourably with results obtained in tests conducted in Europe for cement-bonded particleboard. / Forestry, Faculty of / Graduate

The response of a flake mat to the mechanical stress applied during consolidation is a function of mat structure, raw material properties and the environmental conditions created during pressing. This research project was aimed at improving the understanding of raw material behavior during the hot-pressing of wood based composites by examining the response of a wood flake mat to the compression encountered during press closure in the flakeboard manufacturing process. The structure of a flakeboard mat can be considered to be that of a cellular material, the properties of which are governed by the cellular geometry, or arrangement of cells, and the properties of the solid cell wall material. A method for quantifying the cellular structure of a wood flake mat was developed and implemented. The structure of thin mat sections and small flake mats was quantified using image analysis techniques. The applicability of theories developed for modelling the compressive behavior of cellular materials to the consolidation of wood flake mats was investigated using thin mat sections. Narrow mat sections and small laboratory mats has similar void sizes but significantly different void shapes. Void size was not significantly affected by flake orientation, but void shape was. / Master of Science

In an attempt to relate different pressing parameters to changes in test flake properties, eight hot-press cycles were used in the manufacture of 24 flakeboard panels, with 2 levels each of platen temperature, initial mat moisture content, and press closing time. Temperature and gas pressure occurring at the face and core of the mat, along with platen pressure, were recorded throughout the press cycles. Data is presented graphically as a function of press time. Face and core equilibrium moisture content conditions throughout the press cycle were estimated for each panel based on corresponding temperature and gas pressure information. Time-integral data on temperature, gas pressure, and platen pressure were determined. Simple linear regressions were performed in an attempt to relate the actual test flake environment to changes in properties. Two hundred and fifty yellow-poplar (<u>Liriodendron tulipifera</u>) test flakes were consolidated within the face and core of flakeboard mats and recovered. Their individual pre- and post-pressing thickness and specific dynamic bending modulus values were determined and compared with respect to changes in pressing parameters. Platen temperature, initial mat moisture content, and test flake location within the mat were all involved in significant two-way interactions in their effects on flake properties. / M.S.

The area of penetration of phenol-formaldehyde resin into aspen (<i>Populus tremuloides</i>) and Douglas-fir (<i>Pseudotsuga menziesii</i>) flakes, and the layer properties of yellow poplar (<i>Liriodendron tulipifera</i>) flakeboard were investigated to determine how they were influenced by various pressing parameters. The evenness of penetration was found to be a function of the natural variability of the wood and was not influenced by the pressing parameters of temperature, moisture content, pressure, or time. These four parameters were found to influence the area of penetration by controlling the viscosity and flow of the resin. The temperature, gas pressure, and platen pressure history at any particular plane through a flakeboard panel thickness were found to be directly and interactively determined by the pressing parameters of platen temperature, initial mat moisture content, and press closing time. The specific gravity profile was observed to be a function of the press closing time while platen temperature and the mat moisture content influenced the amount of springback which the panel exhibited. Layer-shear and the corresponding specific gravity at a particular plane were found to be similarly dependent on environmental history. The layer-shear strength increased consistently toward the surface of the panel and exhibited a lower coefficient of variation nearer the surface. / M.S.

Mat conditions of temperature and gas pressure were measured in three locations for one conventional and four steam-injection press schedules used in the laboratory scale manufacture of aspen (Populus grandidentata and Populus tremuloides) flakeboard. Two resins, phenol formaldehyde and polymeric MDI, were used. Steam-injection press schedules varied from low steam input to high steam input by adjusting steam pressure, steam time, and the density range for steam-injection during press closing. Steam-injection rapidly raises mat core temperatures as compared to conventional pressing. Temperature and gas pressure were positively correlated with the amount of steam input. Flakeboard strength and dimensional stability properties were tested. Steam-injection pressing produced panels with superior dimensional stability as compared to conventional pressing. The high steam press schedule produced internal bond and shear strengths equal to the conventional press schedule for phenol formaldehyde. Medium steam press schedules produced superior internal bond and shear strengths to the conventional press schedule for polymeric MDI. The conventional press schedule produced superior static bending MOR strengths for both resins. A fluorescence microscope was interfaced with a digitizing image analysis system to measure resin penetration area on flakes recovered from inside of the mat. Wood anatomy was found to be the dominating factor in creating high variablity in resin penetration area measurements, as differences could not be detected due to the press schedules or resin type. / Master of Science

O OSB é um produto derivado da madeira desenvolvido nos Estados Unidos em 1970. É definido como um painel de partículas orientadas, as quais são distribuídas em camadas múltiplas de uma forma predeterminada. À época, o OSB foi criado para substituir o painel de madeira compensada. Todavia, geralmente suas propriedades na flexão estática são inferiores. A proposta principal deste trabalho foi produzir e analisar o desempenho de painéis OSB de Pinus sp e resina poliuretana à base de óleo mamona com inclusão de telas metálicas, objetivando acréscimo nas propriedades de resistência e de rigidez na flexão estática. A produção seguiu o processo laboratorial, consistindo em gerar as partículas, distribuir o adesivo, confeccionar o colchão e prensar à temperatura de 100°C por 10 minutos. O teor de resina adotado foi de 12% tendo como base a massa seca das partículas. Os painéis foram confeccionados com três camadas, as externas tendo direção paralela ao comprimento da chapa e a interna com distribuição randômica. A proporção face/miolo/face foi na faixa de 20:60:20. Com base nas recomendações de documentos normativos brasileiros e europeus foram realizados ensaios de flexão estática, de onde foram determinados os módulos de ruptura (MOR), e módulo de elasticidade (MOE), ensaios de arrancamento de parafusos, adesão interna, teor de umidade, absorção de água, inchamento em espessura e determinação da densidade aparente. Os resultados apontam a eficiência dos painéis OSB produzidos quando comparadas suas propriedades com os valores mínimos exigidos pelas normas e valores encontrados na literatura para painéis desta natureza. A utilização da tela metálica se mostrou não necessária, dada a pouco relevante diferença de MOE e MOR entre os painéis com e sem a tela. / OSB is a wood based product developed in the United States, since 1954. It\'s defined as oriented particles panels, which are distributed in multiple layers of a predetermined shape. At the time, the OSB was created to replace the plywood panel, but usually its bending properties are inferior. The main purpose of this study was to produce and analyze the performance of OSB from Pinus sp and castor oil based polyurethane resin with inclusion of metallic gauzes, aiming to increase strength and stiffness properties in static bending. Panel production followed laboratory process, consisting of particles generation, adhesive distribution, mattress making and a pressing in 100ºC temperature for 10 minutes. The resin content was set at 12% based on particles dry weight. Panels were produced with three layers: the outers with strands in direction parallel to the panel length; internal in randomized distribution. Face/core/face particle proportion was in range of 20:60:20. Based on Brazilian and European codes recommendations, several tests were performed to determine: modulus of rupture (MOR) and modules of elasticity (MOE), in static bending; screw pullout; internal adhesion; moisture content; water absorption; thickness swelling and density. Results showed efficiency of OSB produced comparing their properties with basic codes requirements the standards and literature values for such panels. The use of metallic gauze has been shown not necessary, because of small relevant difference between MOE and MOR for panels with and without gauze inclusion.

Abstract not available

Thesis (M.S.M.E.)--Baylor University, 2008. / Includes bibliographical references (p. 54).