Edvá Oliveira Brito

Utilização de fibras (epicarpo) de babaçu como matéria-prima alternativa na produção de chapas de madeira aglomerada

O objetivo deste trabalho foi avaliar a utilizacao de fibras (epicarpo) de babacu (Orbignya spp) em combinacao com particulas de Pinus elliottii em diferentes proporcoes na confeccao de chapas de madeira aglomerada, bem como avaliar o efeito de dois teores de adesivo a base de ureia-formaldeido. As chapas foram prensadas a 160 oC, utilizando-se dois niveis de resinas (6 e 8%, base peso seco de particulas) e tempo de prensagem de 10 min, obtendo-se oito tratamentos. Para cada tratamento foram feitas tres repeticoes, totalizando 24 chapas, com densidade nominal de 0,70 g/cm3. As propriedades avaliadas foram: flexao estatica - modulo de ruptura (MOR) e modulo de elasticidade (MOE); tracao perpendicular-ligacao interna (LI); estabilidade dimensional - inchamento em espessura (IE) 2 e 24 horas e absorcao de agua (AA) 2 e 24 horas, de acordo com a norma ASTM D 1037-91. O aumento do teor de fibras de babacu associado ao aumento no teor de adesivo contribuiu para a reducao nos valores de inchamento em espessura e absorcao de agua. O aumento do teor de adesivo de 6 para 8% foi fundamental para a melhoria das propriedades inchamento em espessura, absorcao em agua, modulo de ruptura e modulo de elasticidade. Utilizando ate 30% de fibras de babacu na composicao das chapas, os valores de MOR foram superiores aos estabelecidos pela CS 236-66.

Produção de chapas de partículas de madeira de duas espécies nativas da Mata Atlântica e suas combinações.

The aim of this work was to manufacture strand and shaving particleboards from Schizolobium parahyba and Erytrina verna and their combinations. The parameters of manufacture were: nominal density 0,65 g/cm³, press temperature 180 oC, pressing time 14 minutes, resin content 8% (phenol-formaldehyde), particle moisture content 5% (dry weight basis). The best results of static bending tests were found when guapuruvu pure and/or in the face layer was used, although the majority of the treatments presented superior values to when to campared the Canadian Standard (CSA O437-0, 1993). In relation to internal band, 50% of the treatments presented larger values than established by the Canadian Standard. The values of water absorption and thickness swelling were considered high for all the treatments, having to consider that paraffin was not used during board manufacturing.

CHAPAS AGLOMERADAS CONFECCIONADAS COM UREIA-FORMALDEÍDO SOB ADIÇÃO DE TANINO EM PÓ

This work aimed to evaluate the technological properties of particleboards manufactured with particles of Acacia mangium and urea-formaldehyde adhesive by addition of powder form commercial tannin of Acacia mearnsii to their particles. The boards manufactured under different compaction ratio and the effect of these in the properties of the boards evaluated. It used a completely randomized design in the factorial outline 4 x 4 as follows: four percentages of substitution of powder form tannin to the adhesive urea-formaldehyde - 0, 10, 20 and 30%; and four nominal compaction ratios: 1.39, 1.55, 1.73, and 2.00. The pressing cycle used was 3.92 specific pressure with temperature of 140oC by 8 minutes. The addition of powder tannin to particles with urea-formaldehyde provided some improvements in the physical and mechanical properties. The results indicate that the addition of tannin powder is a viable alternative of use in particleboards, with no need for dilution.

Utilização da farinha de babaçu como extensor alternativo na produção de painéis compensados

This work aims at evaluating the potentiality of babacu flour under differents percents (0%, 50%, 75%, and 100%) as alternative extensers to wheatmeal for plywood manufacturing. Third three panels with five veneers were produced using Araucaria angustifolia (Bert.) Ktze, with urea-formaldehyde – UF and phenol-formaldehyde – FF resins and being three panels per treatment. The following formulations (in parts per wheight) were used: UF resin – 100 x extender – 50 x water – 50 x catalyst – 7 and FF resin – 100 x extender – 18 x water – 22. The results of both glue line shear strength obtained for plywood manufactured with urea-formaldehyde and phenol-formaldehyde resins showed the feasibility of the use of babacu flour as the extender in parcial or total substitution of wheat flour in the plywood manufactures.