Effect of tannin and calcium lignosulfonate-based adhesives on particleboards production

Abstract

Laboratory tests were carried out to evaluate the feasibility of producing particleboards with sugarcane bagasse and Eucalyptus sp. and adhesives (tannin pure and lignosulfonate (tannin + lignosulfonate in the proportion of 80:20)). The adhesives were characterized (pH, gel time, viscosity, and density), and the physical and mechanicals properties was realized (water absorption and thickness swelling, moisture content, gravimetric density, density profile by X-ray, elasticity and rupture modulus, and internal bond).The particleboards showed some homogeneity in density. As to the thickness swelling, the means varied from 24.15 % to 35.57 %, with higher averages for those particleboards that used lignosulfonate adhesive. The same effect could be seen in the water absorption test, with emphasis on the tannin-lignosulfonate adhesives, with averages 18.5 % higher than those of pure tannin, regardless of the type of material. Based on the internal bond test, the highlight was the treatment with 100 % wood particles and pure tannin adhesive. As sugarcane bagasse was added, there was a reduction in modulus of elasticity, independently of the adhesive used. The results highlighted the using lignosulfonate as a component obtained inferior results when compared to those of pure tannin, mainly concerning humidity and the internal bond test. As well as a gradual loss of strength as the wood was replaced by sugarcane bagasse. In this aspect, environmental issues are gained as waste is used; in such uses, such properties are not required.