The Effects of organoclay on the morphology, thermal stability, transparence and hydrophobicity properties of polyamide − imide/nanoclay nanocomposite coatings

In this study, the morphology, optical transparency, thermal properties and contact angle of solvent based polyamide − imide (SBP)/clay nanocomposites coatings were investigated. For this work, the nanocomposites (NC)s of SBP and different amounts of organoclay (Cloisite 20A) were prepared by solution intercalation technique. Finally, SBP/C20A NCs containing 1, 3 and 5 wt% of C20A were mixed via mechanical agitation and ultrasonic homogenizer and applied on cold-rolled steel (CRS) and glass substrates. The structures of exfoliation, intercalation, and aggregation feature were confirmed by wide-angle X-ray diffraction (WAXD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray map (EDS-mapping) analysis. The formation of SBP and NC was confirmed by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The hydrophobicity, thermal stability and optical transparency of the coatings were also investigated using contact angle (CA) measurement with distilled water, thermogravimetric analysis (TGA) and UV-vis spectroscopy, respectively. Thermogravimetric analysis and hydrophobicity results showed that the addition of 1 and 3 wt% C20A into the SBP matrix increased the thermal decomposition temperatures and the CA of as-obtained nanocomposites compared to the pure SBP and NC5%. Furthermore, UV-vis spectroscopy and photograph results confirmed that the optical transparency of the NCs was reduced.