From soda bagasse lignin

In this chapter, the development of a thermosetting adhesive from soda bagasse lignin is described. The research has concentrated on the development of interior-grade adhesives for particleboard. The local market for exterior boards is smaller than that for the interior panels, and adhesives for exterior boards are already covered by an excellent range of tannin-based adhesives. 

Table IV. Internal Bond Strength of Particleboard, 12-mm-Thick, Prepared from Soda Bagasse Lignin Adhesives (10% on Dry Chips) After Pressing at 170 °C for 15 Minutes...

The alkali lignins used were selected from different industrial origins in order to have a wide variation in their properties. The lignins were a kraft softwood, soda/AQ hardwood and soda bagasse lignin (Table II). 

Lignin was obtained from an industrial soda bagasse spent liquor as before (5). The lignin was initially evaluated as a thermosetting adhesive by the beech strip test. Prior to its application as adhesive, the lignin was reacted with formaldehyde in alkali at temperatures below 60 °C to afford a hydroxymethylated lignin (fi). The hydroxymethylation reaction was done at pH 12 and 13, and samples of the reaction mixtures were evaluated on beech strips with overlaps of 25 x 25 mm, cured for 4 hours at 90 °C and 12% equilibrium moisture content. 

Hemicellulose was reclaimed from industrial soda bagasse spent pulping liquor by precipitation with methanol as was done in earlier studies 2-5). The hemicellulose precipitate obtained was submitted to different degrees of washing with 50% aqueous methanol, resulting in hemicellulose preparations containing different quantities of ash and lignin. The pH of the hemicellulose was adjusted and borax or CaCh added, after which it was dried and ball-milled to the indicated particle sizes. 

Preparation of Materials. Soda lignin was prepared from bagasse by subjecting to soda cooking conditions (11), namely,... 

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