Properties of Glued Laminated Timber Made from Fast-growing Species with Mangium Tannin and Phenol Resorcinol Formaldehyde Adhesives

Abstract

This study characterized the chemical compounds in tannin from mangium (Acacia mangium) bark extract and determined the physical–mechanical properties of glued laminated timber (glulam) made from sengon (Falcataria moluccana), jabon (Anthocephalus cadamba), and mangium wood. The adhesives used to prepare the glulam were based on mangium tannin and phenol resorcinol formaldehyde resin. Five-layer glulam beams measuring 5 cm × 6 cm × 120 cm in thickness, width, and length, respectively, were made with a glue spread of 280 g/m2 for each glue line, cold pressing at 10.5 kgf/cm2 for 4 h and clamping for 20 h. Condensed mangium tannin consisted of 49.08% phenolic compounds with an average molecular weight of 4745. The degree of crystallinity was 14.8%. The Stiasny number was 47.22%. The density and the moisture content of the glulams differed from those of the corresponding solid woods with mangium having the lowest moisture content (9.58%) and the highest density (0.66 g/cm3). The modulus of rupture for all glulam beams met the JAS 234-2003 standard but the modulus of elasticity and the shear strength values did not. Glulam beams made with tannin had high delamination under dry and wet conditions, but glulam made from sengon and jabon wood met the standard’s requirements. All glulam beams had low formaldehyde emissions and were classified as F**** for formaldehyde emissions according to the JAS 234 (2003) standard.