Valorization of Solanum Elaeagnifolium Cavanilles Weeds as a New Lignocellulosic Source for the Formulation of Lignin-Urea-Formaldehyde Wood Adhesive

Solanum Elaeagnifolium Cavanilles (SE-Cav) is an invasive plant that has been developed in Mediterranean basin countries especially in Morocco. This weeds which belongs to lignocellulosic biomass allows possibility to insulate lignin. This work attempts to isolate lignin from SE-Cav applying alkali treatment. The obtained lignin was characterized by different complementary analysis (FT-IR; H-1 NMR; C-13 NMR; EDX-SEM and TGA/DTG). On the other hand, lignin was subjected to wood adhesive formulation as partial substitution to urea-formaldehyde (UF). Lignin to UF ratio was (5:95, 10:90, 15:85 and 20:80; w:w). Particleboards bonded with optimal lignin: UF (15:85; w:w) adhesive exhibited excellent mechanical properties (modulus of elasticity, modulus of rupture and internal bond strength) compared to other formulations and control (lignin:UF, 0:100; w:w). Besides, the optimal formulation shows the same behaviours in wet conditions compared to control UF. Moreover, particleboards bonded with the optimal formulation lignin: UF (15:85; w:w) showed a significant decrease in formaldehyde emission levels as compared to control UF.

Automated summary

This study successfully isolated lignin from SE-Cav using alkali treatment and applied it in wood adhesive formulation, showing excellent mechanical properties, water resistance, and a significant decrease in formaldehyde emissions.