This study aimed at evaluating the effect of thermo-mechanical treatment on properties of Pinus caribaea var. hondurensis wood. Two pressure levels (25% and 50% of the compression strength perpendicular to grain) were evaluated. The treatment was applied in a laboratory hot press in one-step or two-step modes for 50 minutes. In the one-step treatment, the total pressure was applied after the temperature of the center of the wood reached 170°C. In the two-steps treatment, half of the pressure was applied after the center of the wood reached 100°C, and the final pressure was applied when it reached 170°C. The weight loss immediately after treatment was equivalent to the wood moisture content, indicating that degradation of wood polymers did not occur. However, the treatments showed decreasing values of the moisture content, which were reduced from 12.3% to 9.8%. A moderate improvement on surface roughness was achieved, while wood wettability was highly reduced in all treatments, as determined by contact angle measurement. On the other hand, the treatment applied did not improve the wood dimensional stability, but all mechanical properties presented a trend of improvement.

RESUMOEste estudo teve por objetivo avaliar a ação do tempo de exposição ao intemperismo artificial na cor de lâminas de madeiras de teca tratadas com produtos de acabamento. Amostras que receberam 2 tipos de produto, a seladora e o stain, mais as testemunhas, sem acabamento. O experimento foi instalado no delineamento inteiramente casualizado, com 3 tratamentos e 4 repetições. As lâminas ficaram expostas ao simulador QUV-Acelerated Weathering Teste, por 7 períodos, de: 6, 12, 24, 48, 96, 192 e 384 horas. Após cada período de intemperismo foram feitas medições das cores, com espectrofotômetro COLOR EYe XTH. As variáveis cromáticas avaliadas foram: L*, a*, b*, C e h*. Ao final do estudo pôde-se concluir que as lâminas de madeira de teca sofreram alterações em sua cor com o passar do tempo de exposição e que o stain apresentou maior eficiência na conservação da cor da madeira.Palavras-chave: teca, fotodegradação, colorimetria, seladora, stain. Artificial Weathering in Tectona grandis Slides Treated with Finishing Products ABSTRACTThis study aims to evaluate the effects of weather exposure to artificial weathering in the color of teak wood veneer treated with finishing products. The samples received 2 types of products, the sealer and the stain, plus witnesses, unfinished. The experiment was conducted in a completely randomized design with 3 treatments and 4 replications. Slides were exposed to QUV-Accelerated Weathering Test simulator for 7 periods as follow : 6, 12, 24, 48, 96, 192 and 384 hours. Color measurements were made after each period of weathering using the spectrophotometer Color Eye XTH. The chromatic variables evaluated were: L *, a *, b *, C * and h*. The study concluded that the teak wood veneer had color alterations with the exposure time and the stain was more efficient in preserving the wood color.

This study investigated the effects of different treatments of coir fibers (Cocos nucifera L.), and cement:coir ratio on physical and mechanical properties of cement-bonded composites. Three treatments: adding 4% of CaCl2, immersion in hot water at 80°C for 90 minutes, and immersion in NaOH aqueous solution at 5% for 72 hours and two cement:fiber ratios (3:1 and 4:1) were chosen for manufacturing 24 panels. After 28 days of setting, characterization was made through static bending (MOE, MOR), parallel compression (COMP), internal bonding (IB), thickness swelling (TS), and water absorption (WA) (2 and 24 hours of water immersion) tests. Treating coir fibers with hot water provided an improvement in the panel’s properties. This treatment had better results in MOE and COMP. Panels produced with CaCl2 addition were resistant as well; however coir fibers treated with NaOH produced cement/coir composites with unsatisfactory physical and mechanical properties.