Recent developments on ultra-low formaldehyde emitting system of tannin-based adhesive derived from tropical wood barks for wood-based products manufacturing: A review

Abstract

Various bio-based compounds have been attempted for adhesive development, including tannin, lignin, polylactic acid, chitosan, etc., to reduce the use of formaldehyde as well as the formaldehyde emission. Among them, tannins demonstrating as the most interesting compound, since tannin has very similar structure with synthetic phenol and has identical reactivity and chemical cross-linking with formaldehyde. As the greatest amount of tannin was found in the tree bark, therefore, this article aims to review the previous development of tannin-based adhesive generating from tropical wood barks and their performance on the manufacturing of several types of wood-based products. The properties of tannin and tannin-based adhesive from several types of tropical wood barks are presented in this review, as well as the physical and mechanical characteristics of wood-based product manufactured with tannin-based adhesive.