, utilizando a resina uréia-formaldeído na proporção de 8% de sólidos -base peso seco das partículas. Os painéis foram prensados com pressão específica de 4,0 MPa, temperatura de 160 ºC e tempo de prensagem de oito minutos. As avaliações dos resultados de ensaios obtidos nesta pesquisa indicam a viabilidade técnica de utilização das nove espécies provenientes de florestas tropicais da Amazônia na produção de painéis de madeira aglomerada, com destaque para Ecclinusa guianensis Eyma (Caucho) que, de uma forma geral, apresentou melhores resultados de propriedades físico-mecânicas. PALAVRAs-CHAVe: Painéis aglomerados, madeiras tropicais, uréia-formaldeído. , using the urea-formaldehyde resin in the proportion of 8% of solid content based on oven dried wood particles. The boards were pressed at the specific pressure of 40 kgf/cm², temperature of 160 ºC and press time of eight minutes. The evaluations of test results obtained in this study indicate the potential use of the nine species from Amazon rainforest in the production of particleboard, highlighting Ecclinusa guianensis (Caucho) that, in general, showed better results of physical and mechanical properties. Evaluation of the properties of particleboard made from sawmill waste of nine tropical wood species of Amazon

RESUMOEste trabalho teve como objetivo avaliar o potencial de uso de resíduos originados da produção de painéis compensados, MDF e MDP para fabricação de painéis aglomerados. A resina ureia-formaldeído (UF) foi utilizada na produção dos painéis, em proporções de 6% e 10% com base no peso seco das partículas de madeira, juntamente com 2% de catalisador (base sólido de resina) e 1% de parafina (base peso seco das partículas). O delineamento experimental foi composto por 10 tratamentos com três repetições cada, totalizando 30 painéis. Os painéis foram produzidos com resíduos nas proporções de 100%, 50-50% e 33-33-33%. Para avaliação qualitativa, os painéis foram submetidos aos seguintes ensaios das propriedades físico-mecânicas: densidade, absorção de água e inchamento em espessura -24 horas, flexão estática, arrancamento de parafusos (superfície e topo) e tração perpendicular à superfície. Os resultados foram avaliados conforme os requisitos das normas EN e ABNT. As avaliações gerais dos resultados das propriedades físicas e mecânicas dos painéis indicaram a viabilidade técnica de uso de resíduos de MDF, MDP e compensados, de forma pura e misturadas, para produção de painéis aglomerados. A possibilidade de uso de resíduos contribui de forma significativa em termos econômicos e ambientais. Palavras-chave: painéis aglomerados; MDF; compensados; resíduos de painéis. ABSTRACTThis study aimed to evaluate the potential use of plywood, MDF and MDP to manufacture particleboards. The resin urea formaldehyde (UF) was used in the production of the panels in proportions of 6% and 10% based on dry weight of wood particles, along with 2% of catalyst, and 1% of paraffin. The experiment comprised 10 treatments with three replicates each, totaling 30 panels. The panels were manufactured with residues in the proportions of 100%, 50-50% and 33-33-33%. The panels were subjected to the following tests of physical and mechanical properties: board density, water absorption and thickness swelling -24 hours, static bending, screw withdraw strength (surface and top) and tension perpendicular to surface (internal bond).The results were evaluated according to the requirements of EN and ABNT standards. The general evaluation of the results of physical and mechanical properties of the panels showed the technical feasibility of the use of residues of MDF, MDP and plywood and their mixtures for particleboard manufacture. The possibility of the use of these residues contributes in terms of economical and environmental issues.

Esta pesquisa teve por objetivo avaliar a viabilidade de uso de lâminas de madeira de Schizolobium amazonicum (paricá) na produção de painéis compensados. Foram produzidos compensados com cinco lâminas de 2,0 mm de espessura, coladas com resinas ureia-formaldeído (UF) e fenol-formaldeído (FF), com duas diferentes formulações de cola e gramaturas. Foram avaliadas as propriedades de resistência da linha de cola (RLC) e flexão estática (MOE e MOR) paralelo e perpendicular. As diferentes formulações de cola e gramatura não afetaram significativamente os resultados de resistência da linha de cola. Os valores médios de RLC e falhas na madeira atendem aos requisitos da norma EN 314-2 (EUROPEAN COMMITTEE FOR STANDARDIZATION (CEN), 1993). Os resultados de MOE e MOR, sentido paralelo e perpendicular, obtidos para os compensados de paricá foram inferiores em relação aos painéis comerciais de Pinus taeda. Entretanto, a baixa massa específica dos painéis de paricá, entre 0,32 e 0,37 g/cm³, em relação aos painéis de pínus de 0,53 g/cm³, não influenciou de forma proporcional na redução dessas propriedades. Os resultados obtidos indicam a viabilidade de uso de lâminas de paricá para fabricação de painéis compensados.Palavras-chave: Compensados; paricá; lâminas de madeira. AbstractEvaluation of plywood quality manufactured with veneers of Schizolobium amazonicum. This research was developed to evaluate the feasibility to use the veneers of Schizolobium amazonicum (paricá) for plywood manufacture. The plywood was manufactured with five veneers of 2.0 mm thickness, using urea-formaldehyde and phenol-formaldehyde resins with two different adhesive formulations and amount of glue spread. Were evaluated the properties of glue line shear strength (RLC) and static bending (MOE and MOR) parallel and perpendicular. The different adhesive formulations and amount of glue spread not affected significantly the results of glue line shear strength. The average values of RLC and percentage of wood failures of the Paricá plywood attends the requirements of EN 314-2 (EUROPEAN COMMITTEE FOR STANDARDIZATION (CEN), 1993). The results of MOE and MOR, parallel and perpendicular, obtained to Paricá plywood were lower than the commercial plywood of Pinus taeda. However, the lower density of Paricá plywood (0,32 to 0,37 g/cm³) in comparison to pinus plywood (0,53 g/cm³), not affected significantly to reduction of these properties. The results obtained in this research showed the feasibility of the use of veneer of Paricá for plywood manufacture.Keywords: Plywood; paricá; veneers.

A study of vacuum-deposited organic-inorganic hybrid coatings for UV protection of polycarbonate is presented. UV-absorbing compounds, which are commonly used for polycarbonate, were embedded in a silica matrix by thermal co-evaporation under high vacuum. In addition to the optical properties of the coatings, the influence of the silica network on the organic UV absorber and the stability of the intramolecular hydrogen bond (IMHB) are discussed. A model is presented to show the interaction between the organic compound and the silica matrix. It could be shown with UV irradiation experiments that the hydroxyphenyltriazine compound exhibits higher UV stability in the hybrid coating than the hydroxybenzotriazoles

This study aimed to evaluate the bonding quality of plywood panels from Pinus taeda using low and high molecular weight phenol-formaldehyde resin and veneers from three different density classes. The experiment consisted of six treatments, each of which produced three panels (replicates). Tests were conducted to evaluate glue line strength to shear stress after two boiling cycles and after 24 hours of cold water immersion. Also determined was the percentage of defects in wood samples. Results indicated that the density classes being assessed differed statistically. However, no significant difference was found between panels produced with high and panels produced with low molecular weight resin as to the mean values of glue line strength, whether subjecting them to two boiling cycles or after 24 hours of cold water immersion. Interactions between different density classes and adhesive formulations were found not significant either. Low molecular weight resin (BPM) and panels produced with higher density veneers were found to have better behavior, regarding both bonding strength and percentage of defects. It was concluded that the bonding quality of plywood panels from Pinus taeda was satisfactory after using different densities of veneer and also high and low molecular weight phenolic resins. All treatments were found to comply with minimum requirements established in European standard EN 314-1/1993, which addresses bonding quality of plywood panels.Key words: Plywood panels, Pinus taeda, veneers, phenol-formaldehyde. PRODUÇÃO DE PAINÉIS COMPENSADOS DE Pinus taeda COM LÂMINAS DE DIFERENTES DENSIDADES E RESINA FENOL-FORMALDEÍDO COM ALTO E BAIXO PESO MOLECULAR RESUMO: Neste trabalho, objetivou-se avaliar a qualidade da colagem de painéis compensados de Pinus taeda, produzidos com resina fenol-formaldeido de alto e baixo peso molecular, e lâminas de três diferentes classes de densidades. O experimento foi organizado em seis tratamentos, e para cada tratamento foram produzidos três painéis (repetições). Os ensaios de resistência da linha de cola aos esforços de cisalhamento foram realizados após dois ciclos de fervura e após 24 horas de imersão em água fria. Determinou-se, também, a porcentagem de falhas na madeira. Os resultados indicaram que as classes de densidade são