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.