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U ovom radu provodilo se eksperimentalno istraživanje vodoupojnosti polimernih premaza elektrokemijskom impedancijskom spektroskopijom. Za istraživanje koristila su se četiri sustava premaza, dva na bazi vode i dva na bazi otapala, koji služe za zaštitu čeličnih konstrukcija od korozije u uvjetima industrijskog okoliša visoke korozivnosti. Upijanje vode u premaz postignuto je uranjanjem metalnih pločica presvučenih premazom u 3,5% otopinu NaCl. Mjerenje je provođeno svaki sat, prvih 10 sati uranjanja, a potom povremeno sve do 154 sati uranjanja. Snimljeni su impedancijski spektri premaza u području od 100 kHz do 10 mHz, a vodoupojnost je izračunata pomoću Brasher-Kingsburyjeve jednadžbe iz modula impedancije pri 10 kHz. Premazi na bazi vode pokazali su veću vodoupojnost do maksimalno oko 40% od premaza na bazi otapala koji pokazuju vodoupojnost do oko 10% uz zanemarenje korekcijskog faktora kojim se iskazuje postotak polimera u premazu. In this paper, an experimental research about water absorption of the polymer coatings was conducted by electrochemical impedance spectroscopy. Four coating systems were investigated, two of them is water-based paints and two were solvent-based paints which are used to protect the steel constructions from corrosion, under the conditions of highly corrosive industrial environment. Water absorption inte the coating was achieved by immersion if the coated metal plates into the 3,5% NaCl solution. Measurment took place every hour, for the first 10 hours of immersion and then periodically until 154 hours of immersion. Impedance spectres of the coatings were recorded in the renge between 100 kHz and 10 mHz and water absorption was calculated with the help Brasher-Kingsbury equation from the impedance modulus at 10 kHz. Water-based coatings have shown greater water absorption with maximum of 40%, while the solvent-based coatings had water absorption of about 10%, when the correction factor which shows percentage of polymer in the coating is neglected. |
