Effects of Glyoxal on Chemical Structure and Properties of Proteinbased Adhesives

By measuring internal bonding strength of the particleboard and by means of CPMAS 13C NMR analysis, the properties of proteinbased adhesives modified with glyoxal and formaldehyde were comparatively studied with two kinds of typical raw materials rich in protein, i.e., soy flour and gluten. The results showed that there was chemical reaction between glyoxal and protein, the performance of the proteinbased adhesives with glyoxal was inferior to the proteinbased adhesives with formaldehyde because the former had less crosslinking than the latter. The proteinbased adhesives with glyoxal could also be applied to particleboard manufacture if more crosslinker, such as pMDI were added.