Dynamic thermomechanical analysis as a control technique for thermoset bonding of wood joints

Dynamic thermomechanical analysis was used to control and investigate the viscoelastic behaviour, as expressed by the dynamic storage modulus and by tan δ, of wood joints bonded with crosslinking thermosetting adhesives. Phenol formaldehyde (PF), melamine-urea-formaldehyde (MUF), resorcinol-formaldehyde (RF), tannin-formaldehyde (TF) and tannin-hexamethylenetetramine (TH) were the resins used. The approach presented indicated that three parameters, defined as the stiffening coefficient, the softening coefficient and the degradation coefficient, may be of interest in comparing wood joints bonded with different adhesives