O objetivo principal do presente estudo foi avaliar o efeito do tratamento térmico das partículas strand (pré-tratamento) e dos painéis (pós-tratamento) sobre as propriedades físicomecânicas dos painéis, visando principalmente à melhoria de sua estabilidade dimensional. O delineamento experimental se constituiu de sete tratamentos, com a avaliação de: Duas temperaturas de tratamento das partículas (200 e 240°C) por um período de 60 minutos; do póstratamento térmico dos painéis produzidos com e sem a aplicação de parafina na temperatura de 220°C e por um período de 12 minutos; e do aumento do teor de adesivo e a aplicação de parafina em painéis sem tratamento térmico. Para cada tratamento foram produzidos três painéis com densidade nominal de 0,65 g/cm³, colados com adesivo à base de fenol-formaldeído. O ciclo de prensagem dos painéis foi o seguinte: pressão de 35 kgf/cm², temperatura de 160ºC e tempo de 8 minutos. A partir dos painéis produzidos, corpos-de-prova foram obtidos para a realização de ensaios físicos (Teor de umidade, densidade aparente, absorção de água e inchamento em espessura) e mecânicos (Módulo de ruptura, Módulo de elasticidade e Ligação interna), conduzidos conforme as normas ASTM D 1037 (2006) e DIN 52362 (1982). Mediante à análise dos resultados dos ensaios foi possível extrair as seguintes conclusões: Os painéis produzidos com as partículas tratadas termicamente a 240°C apresentaram-se superiores aos outros tratamentos em todas as propriedades físicas avaliadas, sendo portanto o tratamento com a melhor estabilidade dimensional. O pós-tratamento térmico promoveu melhora significativa das propriedades físicas dos painéis sem comprometer as propriedades mecânicas. O pré-tratamento térmico teve efeito mais pronunciado sobre as propriedades dos painéis do que o pós-tratamento térmico, proporcionando a melhoria das propriedades físicas e a diminuição das propriedades mecânicas. O aumento do teor de adesivo e a aplicação de parafina não se mostraram tão eficientes na estabilidade dimensional dos painéis OSB quanto o tratamento térmico aplicado nas partículas na temperatura de 240°C. / The main objective of this study was to evaluate the effect of thermal treatment of strand particles (pre treatment) and panels (post-treatment) on the physical and mechanical properties of the panels, aiming primarily to improve the dimensional stability. The experimental design was consisted of seven treatments, with the evaluation of: two temperatures of particle treatment (200 and 240 °C) during 60 minutes; thermal post-treatment of the panels produced with and without the application of paraffin at 220 ° C during 12 minutes; and the increase in adhesive content and application of paraffin on the panels without thermal treatment. Three panels were produced for each treatment with nominal density of 0.65 g/cm ³, bonded with phenol-formaldehyde adhesive. The pressing cycle of the panels was as follows: 8- minute press time, pressure of 35 kgf/cm ², and temperature of 160 °C. From the panels produced, specimens were obtained to conduct physical tests (moisture content, bulk density, water absorption and thickness swelling) and mechanical (Modulus of Rupture, Modulus of elasticity and internal bonding), tests according to ASTM D 1037 (2006) and DIN 52 362 (1982) standard. Through the analysis of test results it was possible to conclude: The panels produced with the particles thermally treated at 240°C were superior to the others for all physical properties evaluated, and therefore it was treatment with better dimensional stability. The post-thermal treatment caused a significant improvement of the physical properties of the panels without compromising the mechanical properties. The prethermal treatment had an effect on the properties of the panels that was more pronounced than the post-heat treatment, providing improved physical properties and lower mechanical properties. The increase in adhesive content and the application of paraffin were not as efficient in the dimensional stability of OSB as the thermal treatment applied on the particles at 240 ° C.

La toxicité des émissions de formaldéhyde rejetées par les panneaux de particules à base de résines contenant du formaldéhyde motive la recherche de liants alternatifs notamment d’origine naturelle. Ce travail porte sur l’élaboration par thermopressage et la caractérisation physico-mécanique de panneaux de particules sans ou à faibles rejets de formaldéhyde à partir des tiges de kénaf (Hibiscus cannabinus) et de la colle d’os ou de liants végétaux riches en tannins ou en mucilage de plantes tropicales. L’utilisation de ces bioadhésifs a permis d’obtenir des panneaux de bonne résistance en flexion (370 = MOE = 3100 MPa ; 2,01 = MOR = 23 MPa). Un procédé peut être envisagé pour une production de ces panneaux utilisables comme matériaux de construction écologiques / The proven toxicity of lignocellulosic composites based on urea-formaldehyde, phenol-formaldehyde type resins by their formaldehyde emissions cause environmental health problems. A study has been carried out to enhance the development of particleboards of low density with few formaldehyde emissions manufactured with Hibiscus cannabinus core reinforcements and matrix of bone adhesive or tannin material from pod of Parkia biglobosa, stem barks of Pithecellobium dulce and foliar sheath of Sorghum caudatum or mucilaginous material from calyx of Bombax costatum and stem barks of Grewia venusta. Vegetable materials were employed in rough powders or extracts forms, or in mixture with the bone adhesive. The results obtained reveal that bone adhesive was as valuable as the urea formaldehyde resin for manufacturing particleboard with good mechanical properties (MOE: 541 MPa, MOR: 5.23, IB: 0.58 MPa). Tannin and mucilaginous rough materials gave particleboards with bending modulus of elasticity (MOE) ranging from 370 to 400 MPa, bending modulus of rupture (MOR) varying from 2.01 to 3.17 MPa and internal bond (IB) going from 0.06 to 0.28 MPa. Those plant extracts leaded to particleboards with variable mechanical properties (MOE: 484 –1100 MPa, MOR: 2.36 – 5.66 MPa and IB: 0.11 – 0.46 MPa) depending of the nature of the adhesive. Tannin based adhesive gave particleboards more valuable than mucilaginous ones. The association of the bone adhesive with the rough or the extracts of the plants material improved the mechanical characteristics of the panels

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of the present study was to evaluate the performance of particleboards fabricated with different proportions of Eucalyptus grandis Hill ex Maiden wood and polyurethane granular solids from the footwear sector of Três Coroas/RS city, using as a binding agent Elastan 8004/BR®, a pre-polymer modified polyisocyanate MDI based. The proportions of polyurethane granular solids and wood particles used were 0/100, 15/85, 30/70, 45/55 e 60/40% (m/m). The performance of the panels was evaluated by density, moisture content, water absorption and thickness swelling at 2 and 24 hours, tensile strength perpendicular to surface, hardness testing, screw withdrawal, IZOD impact strength, thermal conductivity and acoustic performance in relation to airborne noise. Polyurethane addition caused an increase in dimensional stability of the panels, reducing the values of water absorption and thickness swelling. Tensile strength perpendicular to surface of the panels increased significantly with the increase of polyurethane amount in the composition, indicating adhesion quality between particles of panel and adhesive used. Hardness testing was negatively influenced, indicating that the values decreased with the increasing of polyurethane amount. The highest values of screw withdrawal were found using 30 and 45% (m/m) of polyurethane. The IZOD impact strength of the panels increased with the polyurethane granular solids incorporation in its composition, requiring more energy to break them. The addition of t polyurethane provided a decrease in the values of thermal conductivity of the panels and affected the acoustic performance of the panels in a positive way. / O presente trabalho teve como objetivo avaliar o desempenho de painéis aglomerados confeccionados com diferentes proporções de madeira de Eucalyptus grandis Hill ex Maiden e sólidos granulares de poliuretano provenientes do setor calçadista do município de Três Coroas/RS, utilizando como agente aglomerante 20 partes de Elastan 8004/BR®, um prépolímero de poliisocianato modificado baseado no MDI. As proporções entre sólidos granulares de poliuretano e partículas de madeira empregadas foram 0/100, 15/85, 30/70, 45/55 e 60/40% (m/m). O desempenho dos painéis foi avaliado através da determinação da massa específica, teor de umidade, absorção de água e inchamento em espessura após 2 e 24 horas de imersão, resistência à tração perpendicular à superfície, dureza Janka, resistência ao arrancamento de parafusos, resistência ao impacto IZOD, condutividade térmica e desempenho acústico em relação ao ruído aéreo. O acréscimo de poliuretano ocasionou aumento na estabilidade dimensional dos painéis, diminuindo os valores de absorção de água e inchamento em espessura dos mesmos. A resistência à tração perpendicular à superfície dos painéis aumentou significativamente com o aumento da quantidade de poliuretano em sua composição, indicando a qualidade da adesão entre as partículas de madeira e sólidos granulares de poliuretano e o adesivo utilizado. A dureza Janka foi influenciada de maneira negativa, verificando-se diminuição em seus valores à medida que aumentou a quantidade de poliuretano na composição dos painéis. Os maiores valores de resistência ao arrancamento de parafusos foram encontrados utilizando-se 30 e 45% (m/m) de poliuretano. A resistência dos painéis ao impacto IZOD aumentou com a incorporação de sólidos granulares de poliuretano, sendo necessária maior quantidade de energia para o rompimento dos mesmos. A adição de sólidos granulares de poliuretano proporcionou decréscimo nos valores de condutividade térmica dos painéis e afetou de maneira positiva o desempenho acústico dos mesmos.

Cement bonded particleboards contain organic base and as they are set outside, extreme weather condition, such as frost, chemical defrosting substances or sulphates, cause their degradation. The presence of the organic base in the matrix of the material could be the reason why there is higher probability of degrading when compared with materials containing an inorganic base. It could be partially eliminated by an appropriate surface modification of the slab, which main goal is to weaken the impact of an aggressive environment and to extend the lifespan of the board. On the other hand, the surface modifications based on a polymer base are prone to degrade because of other unfavourable conditions such as UV radiation when compared with the cement bonded particleboard. The classification of the surface modifications and the way of their degradation caused by the aggressive environment in real applications are presented in the theoretical part of the thesis. In the experimental part, appropriate methodical ways of testing the resistance of cement bonded particleboard’s coating system were chosen. Then, the testing and comparing of the physical, mechanical and aesthetic properties of different types of coatings were done. Moreover, a spectrophotometric analysis of the colour shade changes for the different aggressive environment were carried out. Furthermore, microstructures of chosen surface modifications were assessed by using an optical and an electron microscope.

The diploma thesis deals with possibility of utilization raw materials from alternative sources for production of cement-bonded particleboards. In theoretical part the possibilities of modifying composition of cement-bonded slabs with emphasis on their matrix are discussed in detail. On basis of the findings and their evaluation, waste from the formatting of cement-bonded particleboards, micronized limestone, heat sink and high temperature fly ash were selected to the composition modification. The mentioned raw materials were analyzed and subsequently tested as substitutes for the matrix of cement-bonded particleboards in the experimental part. The properties of the proposed materials were tested even in the longer term, including the microstructure.

As all materials used for exterior construction, cement-bonded particleboards also subject to climatic effects, such as frost, chemicals (eg. sulphates) or UV rays. Degradation of theese effects is slightly increased by organic base. Increased susceptibility can be eliminated by a effective coating, which reduces direct contact with aggresive influences on the board and provides longer durability. Theoratical part of this thesis analyzes different types of negatice influences and their effect on durability. Practical part contains selection of specific types of coating and assessment of their mechanical and aesthetic properties including spectrophotometric analysis of color change for each degradation effect.