A new source of natural adhesive: Acacia mangium bark extracts co-polymerized with phenol-formaldehyde (PF) for bonding Mempisang (Annonaceae spp.) veneers

Abstract

Acacia mangium is a fast-growing dicotyledonous tree species and has become the dominating plantation in Malaysia. It was grown particularly as a raw material for veneer, pulp, and paper industries. The chemical properties test in this study showed that the A. mangium tree bark contains higher extractive content as compared to the wood portion (sapwood). Tannin extracts from A. mangium tree bark were found to be rich in phenolic compounds and had the potential to replace conventional phenol-formaldehyde (PF) adhesive used in the plywood manufacturing industry. Tannin adhesive (tannin-paraformaldehyde) prepared from A. mangium bark tannin by cross-linking with paraformaldehyde were used for bonding of Mempisang (Annonaceae spp.) plywood board. However, the resulting bonding strength using tannin adhesive was found to be only suitable for interior grade application. Further extension of its application for interior and exterior grade plywood could be achieved with addition of PF (co-polymerization with resol) during the production process. The optimized formulation of tannin adhesive consists of A. mangium solid extracts (90 parts), commercial PF (10 parts), and paraformaldehyde (3%). Results have shown that the plywood shear strength complies with the requirement for European norms EN 314-1 and EN 314-2:1993, which includes the dry test, cold water test, and the boiling test.

Development a new method for pilot scale production of high grade oil palm plywood: Effect of hot-pressing time

“…The low molecular weight phenolic (LmwPF) resin, with desired solid content (20%, 30%, 40%) that was prepared according to Hoong et al [6][7][8], which is by reacting phenol and formaldehyde in an alkaline condition were used as the filling agent in the pretreatment of OPS veneer. The resin cooking procedure were as the normal PF resin cooking for plywood with, minor modified where the methylolation period was maintained less than 4 h. The specifications of the resin used in this study were shown in Table 1.…”

Adhesives formulated from bark bio-crude and phenol formaldehyde resole

“…Addition of tannins extracted from chestnut wood into PF resins shortened the pressing times by 33% without deteriorating the gluing quality of plywood (Kulvik, 1977). Hoong et al (2011) extracted tannin from Acacia mangium tree bark in water at 75 • C, then prepared a tannin solution of 40% solid content, and formulated the tannin solution with a commercial PF resole at the weight ratio of 50:50, 70:30 and 90:10, to which wheat flour with 3% paraformaldehyde was added as the harder. Results showed the formulated tannin-paraformaldehyde-PF (90 parts tannin, 10 parts commercial PF, 3% paraformaldehyde) adhesive contributed to shear strength meeting the requirement for European norms EN 314-1 and EN 314-2:1993 with respect to dry tests, cold water and even boiling tests on the bonded plywood.…”

Investigation of a New Natural Particleboard Adhesive Composed of Tannin and Sucrose. 2. Effect of Pressing Temperature and Time on Board Properties, and Characterization of Adhesive

“…These materials are considered to be environmentally friendly due to the fact that they incorporate lignocellulosic biomass, which is a renewable resource, as a raw material. Usually, synthetic resin adhesives derived from fossil resources are used in wood-based materials to obtain satisfactory bond performance (Yang et al 2006;Mansouri et al 2007;Krug 2010;Hoong et al 2011). However, as the shortage of fossil resources and the deterioration of global environment have been serious problems, it is necessary to develop renewable resources instead of fossil resources.…”