A novel formaldehyde-free wood adhesive synthesized by straw soda lignin and polyethyleneimine

To eliminate toxic formaldehyde from wood-based panels, a new formaldehyde-free wood adhesive (named OL/PEI adhesive) was synthesized by reaction of oxidized lignin (OL) and polyethylenimine (PEI) in the presence sodium periodate. The curing mechanism clarified Fourier transform infrared spectroscopy (FTIR) solid-state cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS13C-NMR) spectroscopy. results showed that periodate could selectively oxidize wheat straw to produce ortho-quinone, then ortho-quinone OL further react with amino groups PEI form adhesive. as-prepared poplar particleboard investigated regard hot-pressing temperature, time, weight ratio, dosage Under optimum conditions, e.g., hot pressing temperature 180 °C, time 13 min, ratio 1:1, 10%, found disperse evenly into voids among shavings particleboard, followed using tightly bonds between shavings. resulting reached requirement mechanical properties (GB/T 4897.3-2003), higher water resistance properties, better heating resistivity. This study demonstrated way unique properties. material replace bonding.