Lignin from waste black liquor 3‐treated lignin in phenol formaldehyde resin

Bagasse and rice straw lignins undergo different treatments, e.g. acid hydrolysis, oxidation with hydrogen peroxide and thermal treatment, before being used as a partial replacement for phenol in phenol formaldehyde resin. These treatments improved the resin formation properties of the lignin. The effect of these treatments on the improvement of the properties of the resin produced has the following sequence: lignin treated with HCl (1‐3N) > lignin treated with H₂O₂ (1‐3 per cent) > thermally treated lignin (120‐140°C). The improvement of the properties of the resin produced from bagasse lignin is greater than that produced from rice straw lignin. The treatment of rice straw lignin with acid increases its ability to form a resin. Treatment of rice straw lignin with acid leads to its increased concentration in the phenol lignin formaldehyde resin with good properties. In general, the resin produced from treated lignin has better properties than resin produced from untreated lignin.