Performance of bonded boards using lignin-based resins

Lignin was extracted from some underutilized plant materials using soda–anthraquinone and soda–anthraquinone–ethanol pulping chemicals. Soda–anthraquinone–ethanol gave higher lignin yield, ranging from 44.47% to 50.41% versus 39.40% to 47.92% of soda-anthraquinone. The isolated lignin was used as a partial substitution for phenol in preparation of lignin-phenol-formaldehyde. The free formaldehyde of the resins ranges from 0.25% to 0.67% versus 1.23% of phenol-formaldehyde (PF) resin used as control. The bonding effectiveness of the resin was evaluated when used as glue for board preparation. The density of the board ranges from 333.54 Kg/m3 to 363.84 Kg/m3. The result revealed that Musa sapientum-, Musa parasidiaca- and Tithonia diversifolia- soda–anthraquinone-derived resins, and soda-anthraquinone–ethanol-derived resin of M. parasidiaca and T. diversifolia had boards with better modulus of rupture (MOR) and modulus of elasticity (MOE) than the board obtained using PF resin.