Alkali-treated kraft lignin as a component in flakeboard eesins

Abstract

Southern pine kraft lignin was reacted with NaOH (15 and 20% based on dry lignin) at 170, 200, and 250°C for 30 and 60 min. Sweetgum flake boards bonded with phenolic resins containing 50% hydroxymethylated lignin prepared from some of the alkali treated lignins were compared with boards bonded with a neat PF resin. Results indicate that boards bonded with lignin-containing resins have a satisfactory bending strength. Boards bonded with resins prepared by reacting lignins with phenol and formaldehyde have better internal bond strength and durability than those bonded with lignin-extended resins. However, there is no evident advantage in using alkali treated lignin in the manufacture of phenol-lignin-formaldehyde resins for flakeboard application.

Keywords

Alkaline hydrolysis, kraft lignin, NMR spectroscopy, hydroxymethylation, phenolic resin, flakeboard, sweetgum

Citation

Kuo, Mon-Lin.; Hse, Chung-Yun; Huang, Dee-Hua. 1991. Alkali-treated kraft lignin as a component in flakeboard eesins. Holzforschung 45(1):47-54