Poly(thiourethane-urethane)-urea as anticorrosion coatings with impressive optical properties

•A new S-core monomer is synthesized at room temperature.•Easy and efficient synthesis of SHBPs as solvent free, one-pot multistep.•PTU-PU-urea coatings from SHBP exhibited excellent corrosion resistance.•The PTU-PU-urea coatings also showed impressive optical and antimicrobial properties.

Herein, we report on an easy and efficient way to develop multi-functional and catalyst free, moisture-cured poly(thiourethane-urethane)-urea (PTU-PU-urea) transparent coatings using highly branched sulfur rich hyperbranched polyol (SHBP) and a tri-thiol (TMP-SH). Thiol-yne click chemistry was used to synthesize sulfur containing S-core monomer (B3) and which was reacted with succinic anhydride to develop an acid terminated monomer (A3). Following A3+B3 approach (polycondensation) SHBP was synthesized as solvent free, one-pot multistep. Toluene diisocyanate was successfully reacted with blend of SHBP and TMP-SH in 1.2:1 ratio (-NCO: -OH + SH) to develop the targeted coatings. Structural characterization of aimed compounds was done by using NMR, mid-FTIR, and ESI-MS, cured coatings/films by TGA, DSC, DMTA, UTM, FE-SEM. Optical properties were evaluated using UV-Vis-NIR spectrophotometer and ellipsometer. Results revealed that coatings showed excellent transmittance (>90%) with medium-range of refractive index varying between 1.6012 and 1.5447 in the region 400-800 nm (n = 1.5655 at 550 nm). Tafel plot of the coatings showed the remarkable corrosion resistance (corrosion rate = 1.63 × 10−5mm per year). Moreover these coatings/films demonstrated significant antimicrobial properties.

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