Peanut meal as plywood adhesives: preparation and characterization

Bio-based adhesives have attracted much attention due to its renewable and environment-friendly properties. This study describes a route for the preparation of a new bio-based adhesive from peanut meal. For this purpose, different types of raw materials (hot-pressed peanut meal and cold-pressed peanut meal) were compared. Moreover, the crushing methods and modification agents were investigated in great details. Furthermore, response surface methodology was applied to optimize the preparation conditions of peanut meal adhesive. The apparent viscosity and the Fourier transform infrared spectroscopy (FITR) of peanut meal adhesives were also evaluated to confirm the validity of the optimal preparation conditions. These results showed that hot-pressed peanut meal is a good candidate for adhesive materials and the addition of sodium dodecyl sulfate (SDS) improves the adhesive bonding strength. In addition, the regression model for the peanut meal adhesive preparation revealed statistical significance. Modification time and material liquid ratio had a significant effect on wet strength while the variables of modification temperature and the addition amount of modifier were insignificant. The optimal preparation conditions were determined as follows: modification temperature of 60 °C, modification time of 3 h, ratio of material to liquid of 1:3 and the addition amount of modifier of 3.2%. The average value of the adhesive bonding strength of 1.05 ± 0.07 MPa was obtained, which is close to the predicted value. Under these conditions, the best wet strength and adhesive performance were achieved for the plywood.