Highly transparent castor oil‐derived polyurethane/silica nanocomposite coating synthesized by in situ polymerization

Abstract

AbstractThe automobile paint industry normally consumes petro‐based feedstock as the raw material, which is non‐renewable and emits a higher amount of volatile organic compound, that pollutes the environment. This study focuses on the use of eco‐friendly castor oil (CO) as a substitute for petro‐based feedstocks; while synthesizing polyurethane (PU)‐based automobile clear coats. An acrylate‐PU/nano‐silica (NS) hybrid coating was developed, which was derived from CO‐based polyol. CO was modified by employing a process that includes epoxidation, followed by transesterification, and acrylation to synthesize the required polyols, which is used for acrylate‐PU paint synthesis via the in‐situ polymerization process. Triallyl isocyanurate (TI) modified NS particles were incorporated with the paint matrix by the ultrasonication method to enhance the paint properties. Experimental findings revealed that with the incorporation of NS particles, char residue, Young's modulus, abrasion resistance, and cross‐cut adhesion % increased by 71.31%, 42%, 0.28%, and 5% respectively. Also, glass transition temperature, pencil hardness, nanoindentation depth, water contact angle, and cross‐linking density were increased from −12.16°C, 2H, 3300 nm, 81.71°, and 0.90 mol/m3 to 1.65°C, 3H, 2000 nm, 92.26°, and 1.78 mol/m3 respectively. The UV‐visibility spectra, haze, transmittance, and gloss parameter showed the enhanced optical properties of the paint samples. PU/NS composite coating developed showed equivalent properties as that of the commercial clear coat.