An investigation using a variable radius roll adhesion test (VaRRAT) revealed an irreversible increase in the wet-adhesion in a metal-oxide-polymer system, under specific experimental conditions. This observation is further confirmed by the T g measurements and the ATR-FTIR studies. The increase in wet-adhesion is attributed to late H 2O-catalyzed curing of the previously partially cured polymers (epoxy ring opening), as well as the formation of nanocomposite layer within the epoxy primer matrix, because of precipitation of the nanocrystals including zinc ammine complexes formed as a result of dissolution of the zinc/ aluminum alloy as well as the metal oxide pigments by the amine crosslinker. High activation energy of ∼100 kJ mol -1 indicated a chemical process to be responsible for the adhesion gain.
- Activation energy
- Glass transition