Due to the petroleum crisis in the Seventies, research had the objective of replace part or the entire conventional adhesive, based on petroleum. One way of replacement was the use of natural sources, as the tannins from some species of tree. However, the tannins present some use limitations, which can be overcome by sulfitation and acid hydrolysis. Therefore, the purpose of this study was evaluate the effect of tannina cid hydrolysis and sulfitation, extracted from the bark of Eucalyptus grandis and Anadenanthera peregrina in the kinetic parameters of tannin adhesives using the technique of differential scanning calorimetry (DSC). The tannins were hydrolyzed with acetic acid or hydrochloric acid 10N, using three pH values and three reaction times. The sulfitation was performed in a 5% sodium sulfite solution, in three reaction times. The activation energy, enthalpy and cure temperature of the adhesive were reduced by hydrolysis and sulfitation of tannins, but showed broadband polymerization. The tannins reaction time had no effect on the kinetic parameters.
Differential scanning calorimetry (DSC); Wood adhesives; Natural adhesives
