Phenol-Formaldehyde Plywood Adhesive Resins Prepared With Liquefied Bark of Black Wattle (Acacia mearnsii)

ABSTRACT

In this study, whole bark and tannin-free bark from black wattle were liquefied in phenol in the presence of sulfuric acid catalyst. The resulting solutions were reacted with formalin in basic solution to yield resol resins that had 33% of the phenol replaced by liquefied bark. Preparation of three-ply Southern Pine plywood showed that the resins made with liquefied whole bark performed better than those prepared with tannin-free bark. At low veneer moisture content, panels bonded with the best liquefied bark resin had properties similar to panels bonded with the commercially available phenol-formaldehyde resins that were tested.