Corrosion protection of galvanized sheet by maleic anhydride-g-liquid polybutadiene environmental friendly coatings

Maleic anhydride-g-liquid poly(1,2-butadiene) (MALPB) was modified with diethanolamine (DEA) to prepare anticorrosive coatings by using ethylene glycol monobutyl ether as non-volatile diluents which was considered environmental friendly; their curing processes and anticorrosive performances on galvanized sheet were studied. A robust coating could be obtained through the crosslinking reaction among hydroxyl groups and acids groups, as well as the crosslinking reaction of double bonds by adding peroxides including 0.25% benzoyl peroxide and 1% dicumyl peroxide (wt% of MALPB) as initiators. The Fourier transforming infrared (FTIR) spectra and differential thermo analysis (DTA) results showed that the coatings could be effectively cured at around 260 °C in 5 min. These coatings exhibited good flexibility and adherence on galvanized sheet while their adhesion decreased with the addition of pigments as observed by the digital microscope. As anticorrosive layers on galvanized sheet, these coatings provided effective barriers to electrolyte by impeding their contact with the metal surface; and their anticorrosive capability could be improved by the addition of pigments as observed through the DC polarization tests and salt spray tests.