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

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.