Abstract The rising popularity of various types of wood panels and the advances in manufacturing technology have increased the uses of wood. The bonding of fibers and particles to form panels, however, involves impregnation with resins, such as phenolic adhesives, which delivery desirable quality to the panels due to their insolubility in water, resistance against heat among others, but are also recognized as carcinogenic to humans (IARC, 2004). This study involved measuring the levels of formaldehyde, remaining in wood panels after use and disposal. It was initially evaluated new panels and then examined degraded ones. The results demonstrated significant volatilization of formaldehyde during the degradation process of the panels, with losses of 74.83% for MDF and 85.71% for medium density particleboards (MDP). The results demonstrated significant volatilization of formaldehyde during the degradation process of the panels, with losses of 74.83% for MDF and 85.71% for medium density particleboards (MDP).

ABSTRACT There is just little information about the technological aspects of the wood of Brazilian native tree species, which limits their suitable use. The objective of this study was to evaluate the resistograph amplitudes of the wood from six native tree species in different wood density classes, and correlate them with their wood densities to demonstrate the efficiency of this nondestructive technique. The results of the resistograph analysis divided the species into three classes. Analyses of basic and bulk densities of their wood showed statistically significant differences among the evaluated samples that divided them into four classes. The comparison of resistograph method and observed densities showed only a slight difference among the density classes. Therefore, it was found in this study that resistograph analysis may be used for explaining wood properties as well as achieving satisfactory correlations with their actual values, especially the physical properties of species with high wood density.

Resumo A grande dependência por madeiras das espécies dos gêneros Eucalyptus e Pinus associada à busca por produtos de diferentes qualidades impulsionam estudos acerca de madeiras alternativas para fins industriais, principalmente de espécies do bioma Caatinga, pouco estudado para fins florestais. O objetivo deste estudo foi caracterizar quimicamente a madeira da espécie Pterogyne nitens assim como analisar seu potencial para produção de polpa celulósica. Foram colhidas três árvores representativas de 9 anos, em um plantio experimental localizado na Universidade Estadual do Sudoeste da Bahia - Campus Vitória da Conquista, e amostradas cinco seções do fuste entre as posições 0, 25, 50, 75 e 100% da altura comercial. Os toretes foram transformados em cavacos e homogeneizados formando uma amostra composta representativa para a análise de densidade básica e composição química completa, bem como para a realização da polpação Kraft (cinco cozimentos utilizando diferentes cargas de álcali efetivo objetivando um Número Kappa 18). A densidade básica da madeira Pterogyne nitens foi de 641 kg/m3, sua composição química apresentou 41,9% de celulose, 24,7% de hemiceluloses, 26,5% de lignina, 7,3% de extrativos e 0,5% de cinzas. O rendimento do cozimento para Número Kappa 18 foi 46,4% e viscosidade 1075 dm3/kg. A espécie não se apresentou como uma alternativa interessante para a produção de polpa celulósica (baixo teor de celulose e rendimento depurado), mas bastante promissora para aplicação na área de energia da madeira.

Abstract The strong dependence on wood from species like Eucalyptus and Pinus genus, associated to the search for products of different qualities, led to studies about alternative wood for industrial use, mainly about species from the Caatinga biome and which is understudied for forest purposes. The aim of this study was to characterize chemically the wood from the species Pterogyne nitens and analyze its potential for pulp production. Three representative trees of 9 years old were harvested in an experimental plantation located in the southwest of Bahia state, the University of Vitória da Conquista Campus, and sampled five short logs at 0, 25, 50, 75 and 100% of the commercial height. Logs were transformed in chips and homogenized to obtain a representative composed sample for the total chemical analysis (cellulose, hemicelluloses, lignin, extractives and ashes content) and Kraft pulping (five cooking using different effective alkali loads to establish Kappa number 18). Pterogyne nitens wood basic density was 641 kg/m3, its chemical composition showed contents of cellulose (41.9%), hemicelluloses (24.7%), lignin (26.5%), extractives (7.3%) and ashes (0.5%). Pulping yield at Kappa number 18 was 46.4% and viscosity 1075 dm3/kg. The species did not suggest as an interesting alternative for pulp production (low cellulose content and screened yield), but very promising for application in the biomass energy area.