Natural Tannins for Cold-Setting Wood Adhesives
Flavonoid tannins, from the bark and wood of trees such as Acacia mearnsii and Pinus radiata, being phenolic in nature, undergo the same well-known reaction of phenols with formaldehyde either base- or acid- catalysed, weakly basic base-catalysed reactions being predominantly used in industrial applications. Increasingly alkaline conditions lead to progressive activation of the phenol as nucleophile, especially above pH 8 where phenate ions are formed.
KeywordsReactive Position Methylene Bridge Liquid Resin Simultaneous Synthesis Tannin Adhesive
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