Paricá (Schizolobium amazonicum) and embaúba (Cecropia sp.) as new raw materials for particleboards
In this work two potential new species for forest plantation projects in Northern Brazil were evaluated for their suitability in particleboard production. The main evaluated parameters of the laboratory boards were pH value and buffer capacity of the particles, compaction ratio, thickness swelling, modulus of elasticity (MOE), modulus of rupture (MOR) and internal bond (IB). The results showed that both species are highly suitable for particleboard production as they presented low densities (400–430 kg/m³), light color, good compressibility and no apparent adverse reactions after UF-resination.
PRODUÇÃO DE PAINÉIS AGLOMERADOS COM MISTURAS DE SEIS ESPÉCIES DE MADEIRAS DA AMAZÔNIA E Pinus taeda
This study aimed to evaluate the quality of particleboard produced from the mixture of six wood species of the Amazon and Pinus taeda taeda taeda. The Amazonia wood species studied were: Eschweilera odora, Byrsonima crispa, Swartzia recurva, Eschweilera coriacea, Manilkara amazonica and Pouteria guianensis . The experimental design consisted of a mixture of three tropical species, in a proportion of 50% and Pinus taeda . Experimental panels were produced with 0.75 g/cm³ nominal density, using urea-formaldehyde resin at 8% based on solid dry weight of the particles. The panels were pressed with the following conditions: 4.0 MPa specific pressure, 160 oC temperature and a 8 minutes of pressing time. Despite the differences in density, extractives content and pH of the wood, besides of the board compression ratio, clear interactions between these variables and the properties of the particle boards were not found. Based on comparisons with standard requirements and results for the reference species - Pinus taeda , it can be concluded that the wood of six tropical species studied have potential for particleboard production.
Propriedades de chapas de aglomerado confeccionadas com misturas de partículas de Eucalyptus spp e Pinus elliottii
This work aimed to evaluate properties of particleboards manufactured with particles derived from planner shavings and flakes of Eucalyptus grandis, E. urophylla and E. cloeziana. Pinus elliottii particles were mixed with eucalyptus particles when necessary and in an amount enough to keep boards densities at 0.70 gr/cm3. Eucalyptus wood was obtained from the municipalities of Ponte Alta (Vale do Rio Doce) and Tres Marias (Cerrado Region), both in Minas Gerais state, Brazil. Eucalyptus grandis, E. urophylla and E. cloeziana densities collected in Ponte Alta were 0.55; 0.61 and 0.70 g/cm3 whereas those collected from Tres Marias were 0.58; 0.58 and 0.69 g/cm3, respectively. The density of Pinus elliottii cultivated in the region of Vicosa was 0.45 g/cm3. Particles were produced by processing flakes (0.48 x 20 x 90 mm) and planner shavings in hammer mill. Mean slenderness ratios were 19.87 and 4.66 for particles produced from flakes and shavings, respectively. Urea-formaldehyde adhesive was applied in the proportion of 8% of particle dry mass. Boards manufactured with higher amount of eucalyptus particles absorbed more water and had higher swelling and linear expansion. Highest hardness and parallel compression were observed on boards manufactured with particles from shavings, whereas highest internal bond, modulus of rupture and elasticity values were found for boards fabricated with particles from flakes. Boards made with particles from wood derived from Tres Marias had higher means for parallel compression, internal bond and modulus of rupture.