With the oscillation test we researched rheological properties of phenol-formaldehyde (PF) adhesives during the process of curing at the constant frequency of loading 1Hz in the system wood-adhesive-wood and aluminium-adhesive-aluminium. We researched the influence of the heating rate (10°C/min, 20°C/min, 30°C/min, 40°C/min, 50°C/min in 60°C/min) and types of substrate (aluminium, beech and spruce discs) on storage modulus (G') and loss modulus (G'') of PF adhesives. For the influence of temperature on the G' and G'' of PF adhesives at different heating rate, we used only aluminium discs, since they the best showed characteristic properties during curing. We also researched the influence of the substrate on the gel point and on the point of cross-linking of PF adhesives at different heating rates. It was found out that both moduli, when we used aluminium disks, started to increase earlier, than when we used wood discs. Using the beech discs compared to the spruce ones did not influence on the G' and G'' of PF adhesives. The heating rate of the PF adhesive at all types of substrates influenced on time of curing of the adhesive, which was decreasing with the increasing heating rate. With the use of aluminium discs we found out that with the increasing heating rate of the PF adhesive, the temperature at which the curves of both moduli started to increase, was decreasing. The gel and crosslinking times of the PF adhesive did not differ, irrespective of the substrate type. Larger differences were observed at the gel and crosslinking temperatures of the PF adhesive.
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