Adhesives fromPinus RadiataBark Extractives

Publisher Website
Google Scholar
Abstract
Extracts containing tannins and related polyphenols were obtained from Pinus rudiata bark by extraction with hot water containing small amounts of sodium carbonate and/or sodium sulphite. The extracts had excessive viscosities (< 10 Pa.s) at the concentrations required for adhesive formulation, but this problem was readily overcome by reducing the pH of the extract solution to below 4.5 with acetic acid, adding a small amount of phenol, and heating the mixture. Adhesive performance was best between pH 4.5–6.0, and the bonds were resistant to boiling water. However, joints bonded with early adhesive formulations tended to fail within the adhesive, necessitating some form of adhesive fortification in later formulations. The results obtained with a number of different additives as fortifiers are presented. Softwood plywood which passed the bond quality requirements of the boiling test described in U.S. Product Standard 1-74 was made in the laboratory using these fortified adhesives.

This publication has 2 references indexed in Scilit: