Effect of Nano Silica on Moisture Absorption of Polyurethane Clear Coats as Studied by EIS and Gravimetric Methods

Electrochemical impedance spectroscopy (EIS) and gravimetric methods were carried out to analyze water uptake of thin polyurethane films separately filled with hydrophobic or hydrophilic nano-silica. A gravimetric test method was performed using a simulated ASTM D570 standard technique. Correspondingly the impedance spectra and gravimetric data were interpreted in terms of movement of water within the coating and/or to the coating/metal interface. Type and content of nano silica had significant effects on the capability of water absorption of thin filled coatings. Indeed, it was found that rate and maximum level of moisture absorption of polyurethane coatings heavily depended on the type and loads of nano-silica within the clear coat

کلیدواژه ها:

Nano Silica ، Polyurethane ، Clear Coat ، EIS ، Gravimetry