ABSTRACT The aim of this research was to investigate sugarcane bagasse (SCB) particleboards, using two kinds of particles, from pith and fibers, reinforced with cellulose nanocrystals (NCC). The NCCs were dispersed in the adhesive urea formaldehyde (UF) using a sonificator in two proportions (0 and 1%). The NCCs and UF were applied in the SCB particles using a rotary blender. The particleboards were produced in three layers using two kinds of particles: pith and fibers. After dispersion of the adhesive, the mixture was compressed to produce the particleboards, which were characterized by physical, mechanical and thermal properties. The anatomical and chemical features relating to pith and fiber were very similar. The particleboards made with and without NCCs did not differ statistically for most properties: modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA) thermal conductivity (TC), and the volume heat capacity (VHC). Particleboards made only with fibers and without NCCs showed higher internal bond (IB). In the other hand particleboards made only with fibers in the face and pith in the core (without NCCs) showed lower thickness swelling after 24 hours (TS24h). Probably, the NCCs did not improve the particleboards performance, because less links were available for SCB to interact with the adhesive. For the others properties the particleboards made with pith and fibers did not showed statistical difference (MOE, MOR, TC, WA, TC and VHC), demonstrating that separation of pith and fiber are not significant and does not affect the final properties of particleboards.

ABSTRACT The objective of this study was to evaluate the polyester-based fiber composites reinfor ced with filaments/fibers of mauve treated with NaOH and maleic anhydride. The che mical treatment of the mauve filament/fibers (3 cm of length) was carried out, first with NaOH, followed by maleic anhydride. The resin used was ortho unsaturated polyester with addition of catalyst peroxide methyl ethyl ketone. The composites were prepared with 15% filaments (w/w) and tested for water absorption, three-point bending, tensile and impact strength. Fiberglass composites were produced using the same methodology for comparison purpose. The results demonstrate the potential use of mauve filaments. For some properties, the mauve composites showed better mechanical properties than fiberglass composites (three-point bending and tensile). The treatment of the filaments had varied effect and did not improve the mechanical properties. However, for the water absorption was observed a reduction of 35% in composites with treated mauve filaments.

RESUMO O objetivo deste trabalho foi avaliar a qualidade de painéis particulados produzidos com diferentes formulações, variando percentagens de adesivo e casca de arroz (Oryza sativa L.) adicionadas à madeira de Cunninghamia lanceolata. Três teores de adesivo (6, 9 e 12%) e três proporções de casca de arroz (25, 50 e 75%) foram combinados resultando em 9 formulações. Para analisar a influência de cada matéria-prima na qualidade final dos painéis, sua composição química foi determinada de acordo com os teores de extrativos, componentes minerais, lignina e holocelulose. Os painéis aglomerados foram avaliados pelas seguintes propriedades físicas e mecânicas: absorção de água (AA), inchamento em espessura (IE), ligação interna (LI), compressão paralela (CP), módulo de elasticidade (MOE) e módulo de ruptura (MOR) na flexão estática. Os valores médios das propriedades físicas e mecânicas demonstraram que menores teores de casca de arroz e maiores teores de adesivo ocasionaram melhor desempenho dos painéis. O baixo teor de lignina e alto teor de cinzas da casca de arroz influenciaram negativamente a qualidade dos painéis. Dentre as formulações avaliadas, painéis com inclusão de 25% de casca de arroz e 9% de ureia-formaldeído apresentaram os melhores resultados. Os painéis produzidos neste trabalho são alternativas potenciais para aplicações gerais em condições secas que não demandem alta resistência mecânica. No entanto, o processo e as formulações necessitam ser ajustados para aplicações estruturais mais exigentes.

ABSTRACT This work aimed to evaluate the quality of particleboards made with different formulations, varying adhesive content and rice husk (Oryza sativa L.) proportions added to Cunninghamia lanceolata wood. Three adhesive contents (6, 9 and 12%) and three proportions of rice husk added to wood (25, 50 and 75%) were combined resulting in 9 formulations of particleboards. In order to analyze the influence of each raw material in the final quality of the boards, their chemical composition was determined, including extractive, ash, lignin and holocellulose contents. Regarding the particleboards, the following physical and mechanical properties were evaluated: water absorption (WA), thickness swelling (TS), internal bonding (IB), parallel compression (PC), modulus of elasticity (MOE) and modulus of rupture (MOR) in static bending. For both mechanical and physical properties, average values showed that lower rice husk proportions and higher adhesive contents induced to better performance. Low lignin and high ash contents found in rice husks negatively influenced particleboard quality. Among the formulations tested, the inclusion of 25% of rice husk and 9% urea-formaldehyde presented the best results. Particleboards produced in this work are potential alternatives for general applications in dry conditions that do not require high mechanical resistance. Nevertheless, the process and formulations need to be adjusted in order to reach the requirements for more demanding structural applications.

The aim of this study was to evaluate the potential use of sisal and coir fibers in combination with Eucalyptus particles for the production of particleboard. The particleboards were produced in three layers. The first and third layers (face) were made with small Eucalyptus particles. The second layer (core) was made with big Eucalyptus particles in combination with coir or sisal fibers. The particleboards were prepared with the substitution on Eucalyptus wood for sisal and coir fibers in the particleboards core, in doses of 0, 10, and 20%, relative to the total mass of particles. The particleboards were characterized by mechanical, physical and thermal properties. The results were not satisfactory for particleboards with sisal. However, for coir particleboards the physical-mechanical properties were very similar to those particleboards produced only with Eucalyptus. This work demonstrates the potential use of the coir that is commonly disposed in landfills on the Brazilian beaches.

Objetivou-se, neste trabalho, avaliar a qualidade do encolamento de partículas "strand" e a influência desse processo na qualidade final da colagem em painéis OSB. Realizou-se a mensuração das dimensões e determinação da massa de 658 partículas antes e após o processo de encolamento. As variáveis gramatura (g.m-2) e a quantidade efetiva de adesivo aplicado (%) foram avaliadas. Aplicaram-se os teores de 6, 9 e 12 % de adesivo fenol-formaldeído em partículas de Pinus oocarpa e Eucalyptus grandis. Foi realizado o teste de tração perpendicular nos painéis produzidos. O processo de encolamento de partículas "strand" em laboratório é heterogêneo, o que dificultou analisar a influência das variáveis de processamento sobre a quantidade efetiva de adesivo aplicado e gramatura. Foi verificado que painéis OSB produzidos com a espécie Pinus oocarpa apresentaram menor gramatura de partículas em relação aos painéis de Eucalyptus grandis. Esse resultado foi atribuído a menor densidade básica da madeira de Pinus oocarpa. Observou-se que maiores gramaturas na partícula estão, positivamente, relacionadas com a resistência à tração perpendicular.

This work aimed to evaluate the quality of strand particles gluing and its influence on the final bonding quality in OSB panels. The measurement of the dimensions and determination of the mass of 658 particles were made before and after the gluing process. The variables glue amount (g.m-2) and effective amount of adhesive applied (%) were evaluated. Phenol-formaldehyde adhesive was applied at 6, 9 and 12% contents in Pinus oocarpa and Eucalyptus grandis particles. Perpendicular tension strength test was conducted in the panels produced. The gluing process in laboratorial conditions is heterogeneous, which hinders the analysis of the influence of the processing variables on the effective amount of adhesive applied and glue amount. It was verified that OSB panels made from Pinus oocarpa species presented lower glue amount per particle in relation to Eucalyptus grandis species. This result was attributed to the lower basic density of Pinus oocarpa wood. Increases in glue amount of particles are related to increases in perpendicular tension strength.

The sugar cane bagasse is the most abundant agricultural residue produced in Brazil. It can be used for the production of chipboard panels and as constructive components for several types of environments. The substitution of timber for the bagasse minimizes environmental impacts and contributes to the generation of a new product with lower density and lower thermal conductivity which can improve the thermal conditioning of buildings. This study aims at determining the heat flow through chipboard panels made of sugarcane bagasse and comparing these chipboard panels with similar ones made of Pinus and Eucalyptus. The results show that the heat flow during the heating of the panels is lower for the panels made of sugar cane bagasse and the heat accumulation promoted by this panel is greater than by others. Therefore this product may be suitable to be used as liners, between cavity walls, partition walls and more.

ABSTRACT The purpose of this research was to evaluate the influence of compression ratio on the physical and mechanical properties of particleboards through simple linear models. Panels were produced in three compositions: 1) 100% Toona ciliata; 2) 50% Toona ciliata + 50% Pinus sp.; and 3) 50% Toona ciliata + 50% Eucalyptus sp. For the adjusted models, variance analysis and lack of adjustment test were performed. The models were evaluated according to the significance of their coefficients, estimation standard error and determination coefficient. The Pearson linear correlation between variables was also determined. The elasticity and rupture modulus increased with the increase in compression ratio; the opposite occurred for internal bonding, thickness swelling after 2 hours and water absorption. Except for parallel to face compression and thickness swelling, good adjustments of models were obtained for the other variables.

RESUMO O objetivo deste trabalho foi avaliar a influência da razão de compactação sobre propriedades físicas e mecânicas de painéis aglomerados por meio de modelos lineares simples. Foram produzidos painéis em três composições distintas: 1) 100% Toona ciliata; 2) 50% Toona ciliata + 50% Pinus sp.; 3) 50% Toona ciliata + 50% Eucalyptus sp. Para os modelos ajustados, foram realizadas análises de variância e teste de falta de ajuste. Os modelos foram avaliados de acordo com a significância de seus coeficientes, erro padrão da estimativa e coeficiente de determinação. A correlação linear de Pearson entre as variáveis foi determinada. Os módulos de elasticidade e ruptura aumentaram com o aumento da razão de compactação, tendo o contrário ocorrido para ligação interna, inchamento em espessura após 2 horas e absorção de água. Com exceção da compressão paralela às faces e inchamento em espessura, foram obtidos bons ajustes de modelos para as demais variáveis.

ABSTRACT The physical properties of commercial particle-boards made of sugar cane bagasse and wood were studied. Thickness swelling and water absorption tests were conducted in order to compare the materials and their types of absorption: total, lateral and superficial. Tests for comparison between particle-boards made of different materials showed that sugar cane bagasse particle-boards presented higher water absorption, but lower thickness swelling. For sugar cane bagasse particle-board, the highest value was found for lateral water absorption. For wood particle-board, the total absorption was highest after 2 hours of immersion, but it became equal to the superficial absorption after 24 hours.

RESUMO As propriedades físicas de painéis aglomerados comerciais produzidos com bagaço de cana e madeira foram estudadas. Os testes de absorção de água e inchamento em espessura foram realizados para comparação entre os materiais estudados e entre os tipos de absorção de cada material: total, superficial e lateral. Nos testes de comparação entre painéis de bagaço de cana e painéis de madeira, foi observado que os primeiros apresentaram maiores valores de absorção de água, mas menores inchamentos em espessura. O aglomerado de bagaço de cana apresentou maiores valores de absorção de água lateral. Já no de madeira, a absorção total foi superior após 2 horas, mas igualou-se à absorção superficial após 24 horas.