Development and mechanism characterization of high performance soy-based bio-adhesives

The techniques for denaturing defatted soy flour (DSF) for the production of high performance soy-based bio-adhesives (SBA) have been developed. The developed soy based products from various stages of process were characterized using FTIR and XPS to examine the denaturing mechanisms. The results from the orthogonal statistics [L9(34)] showed that the optimized ratio of DSF:H2O was 2:8 by weight and the best combination of acid:salt:alkali was 2.38:0.002:7.98% total mass of DSF and H2O. The FTIR and XPS spectra illustrated the change of chemical groups and conversion of the protonized products: the amide link hydrolysis and decarboxylation have taken place when DSF was denaturized by acid and salt with the active groups, –NH2, –COOH and –OH, increased. The alkali modification caused some aminolysis with the active groups increased further. Curing SBA made amide links reestablished and hence caused amination, resulting in the improvement of cross-linkage of soy-protein and hence water-resistance.