Utilization of enzymatic hydrolysate from corn stover as a precursor to synthesize an eco-friendly adhesive for plywood II: investigation of appropriate manufacturing conditions, curing behavior, and adhesion mechanism

In this study, further research on an enzymatic hydrolysate-ammonium dihydrogen phosphate (EHADP) adhesive was carried out. Appropriate hot pressing conditions were clarified by measuring the bond strength of three-ply plywood bonded with EHADP adhesive, and the results indicated that the appropriate fabricate conditions were 170 °C and 5 min. The value of wet shear strength fulfilled the requirements of China National Standard GB/T 9846–2015 when plywood was fabricated by the appropriate conditions. In the research of curing behavior, the insoluble mass proportion promoted significantly as heating temperature and time were ≥ 170 °C and 5 min. Furthermore, a pyrolysis gas chromatography/mass spectrometry analysis indicated that adding ammonium dihydrogen phosphate (ADP) catalyzed the conversion of monosaccharides in the EHADP adhesive. The adhesion mechanism of the EHADP adhesive was studied by Fourier transform-infrared spectroscopy analysis, and the chemical changes indicated that the adhesion mechanism was attributed to both mechanical and chemical bonding between the wood elements and the cured EHADP adhesive.