Effect of silica nanocomposite modified with some polythiophene derivations on characteristics and properties of waterborne acrylic coatings

Abstract

In this study, we utilized nanocomposites prepared from nanosilica (SiO₂) and various polythiophene derivatives as enhancement additives for acrylic coatings. The nanocomposites were synthesized in a nitrogen environment using FeCl₃ as a catalyst in a chloroform solvent. The weight ratio of nanosilica to monomers was 2/1, specifically for the compounds (5-benzo[d]thiazol-2-yl)-7-methoxy-2-(thiophen-3-yl)benzo[d]oxazole (P1), 3-(2-benzothiazolyl)thiophene (P2), and 5-(benzo[d]thiazol-2-yl)-2-(thiophene-3-yl)benzo[d]oxazole (P3). Analysis techniques including IR, TGA, SEM, and UV–Vis were employed to demonstrate the formation of polythiophenes on the surface of the nanosilica. The presence of polythiophenes on the nanosilica broadened the UV absorption region. Upon adding the nanocomposites to acrylic coatings, the UV absorption intensity of the coatings was increased. Notably, the coating containing SiO₂-P3 nanocomposite exhibited the highest abrasion resistance among all the investigated samples. By varying the content of SiO₂-P3 nanocomposite, we observed enhanced abrasion resistance, adhesion, pencil hardness, and gloss of the acrylic coating. The maximum values were achieved when the content of SiO₂-P3 nanoparticles was 2 wt.%. The SiO₂-P3 nanoparticles were uniformly dispersed in the acrylic coatings, leading to an improvement in the coating's sunlight-reflective ability. Consequently, the acrylic/SiO₂-P3 nanocomposite coatings exhibited potential for outdoor applications, particularly as UV-resistant coatings.