Effect of urea-formaldehyde adhesive composition on rheological and dielectric properties during curing was examined. The main difference among adhesive samples was different molar ratio between urea and formaldehyde. One sample also contained melamine. Adhesive mixtures were pre-prepared, we just added a catalyst before testing. Tests were made using rheometre ARES-G2, connected to a computer and LCR metre. In this way we gained ability to analyze rheological and dielectric properties together during curing. A sample of a prepared adhesive mixture was applied on aluminium discs. Then we approached discs on a required distance and launched measurement. The heating temperature was set from 30 °C to 85 °C for most of the samples. From the test data, the degree of curing was calculated for each sample. We found out that the molar ratio between urea and formaldehyde affected rheological and dielectric properties, just as an addition of melamine and flour. When the quantity of the catalyst was higher, higher values for both components of shear modulus and conductivity were recorded, and also the curing reaction was faster. On the basis of typical points of adhesive conversion, as gel and vitrification points, a correlation between the results of both methods was detected..Significant similarity among the results of degree of curing calculated out of storage modulus and conductivity was discovered as well.
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