Glulam Properties of Fast-growing Species Using Mahogany Tannin Adhesive

Abstract

Manufacturing glued laminated timber (glulam) can help overcome the limited availability of large-sized timber, and the use of bio-adhesives may resolve environmental problems associated with synthetic adhesives containing high formaldehyde contents. Tannin adhesive is a bio-adhesive that can be used as alternative glue in the manufacture of glulam. The purpose of this study was to determine the physical and mechanical properties of glulam made with mahogany (Swietenia sp.) tannin adhesive and wood from three fast-growing species, namely pine (Pinus merkusii), jabon (Anthocephalus cadamba), and sengon (Falcataria moluccana). Glulam (3 cm × 6 cm × 120 cm in thickness, width, and length, respectively) was manufactured with three layers of lamina. The physical and mechanical properties of the glulams were tested based on relevant standards. The results showed that pine glulam fulfilled the standard for the modulus of rupture and modulus of elasticity, while sengon glulam met the standard for shear strength. In the delamination test, sengon glulam was resistant to immersion in cold water and hot water. All glulams had low formaldehyde emission levels and therefore fulfilled the standard requirements. The results showed that the tannin adhesive from mahogany bark was equal in quality to methylene diphenyl di-isocyanate for glulam manufacturing.