Dynamic oscillatory measurements (time sweep) were carried out in order to examine the
stability of cornstarch-tannin adhesives. In the complex modulus, the elasticity can be described by the storage shear modulus G’, and the viscous property can be described by the loss shear modulus G’’. Figure 1 show the variation of the elastic modulus G’ and viscous modulus G’’ with time at 25 °C, 1 % strain and 1 rad/s of formaldehyde-free cornstarch-tannin adhesives. It can be seen that dynamic modulus (G’ and G’’) increase progressively with time up to 4 hours. Beyond this they remain constant. That shows excellent structural stability of the adhesive. On the other hand, this figure shows a predominant elastic character of the adhesive (G’ > G’’)