Effects of organically modified nanoclay particles on the mechanical properties of aliphatic polyurethane/clay nanocomposite coatings

Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid with the purpose of preparing aliphatic polyurethane nanocomposite coatings. X‐ray diffraction (XRD), thermogravimetric analysis, and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the ion exchange through the silicate layer of nano clay particles. XRD result showed about 5 A° increment in the distance of silicate layers. Transmission electron microscopic images showed good dispersion of modified nanoparticles in polymeric matrix. Mechanical properties of nanocomposites were evaluated using dynamic thermal analysis and tensile techniques. Results illustrated that nanocomposite coatings have higher toughness property and lower brittleness due to the proper nanoparticles dispersion. Morphology of the fractured surface of free films was examined by preparing scanning electron microscopic images; less ruptures and more roughness in the fractured surface of nano composites in comparison to the polyurethane‐free films have been proven. POLYM. COMPOS., 38:1167–1174, 2017. © 2015 Society of Plastics Engineers