Fig. 4 shows a representative 13C NMR spectrum of corn flour, UF and corn flour:UF (7:93) adhesive. The assignments of the different peak shifts observed were both obtained from the relevant literature. This measurement was used to show the reaction between UF and corn flour. Results from Fig. 4 revealed that the spectrum of the corn flour:UF (7:93) adhesive was very similar to that of corn flour and UF. Interpretation of the 13C NMR spectrum suggests that no reaction between corn flour and UF appears to have occurred.