Studies on Biobased Non-Isocyanate Polyurethane Coatings with Potential Corrosion Resistance

This work deals with the development of non-isocyanate polyurethane (NIPU) composites an aniline oligomer, viz., tetraniline (TANI) for corrosion-resistant coatings. Firstly, epoxidizedsoyabean oil was converted to carbonated by inserting CO2 under high temperature and pressure into epoxy ring. Then, varying weights oligoaniline—0.5, 1, 2 4 wt % (based on weight CSBO)—were added CSBO cured tetraethylenepentamine (TEPA, 25 based CSBO) at 80 °C 12–15 h. The effects oligomer loading thermal, mechanical surface wetting properties free standing films were studied. ATR-FTIR spectra exhibited peaks corresponding bis-carbamate linkages, confirming formation urethane linkages. TGA analysis showed that addition oligoaniline did not alter initial degradation much; however, residue increased increasing tetraniline. Both tensile strength elongation (at break) content. While glass transition observed approximately room temperature, i.e., 20–30 °C, all compositions, contact angles found be less than bare NIPU films. However, compositions hydrophobic, exhibiting in 98–110° range. SEM cross-sections confirmed uniform distribution particles morphology roughness from 0.5 4%. MS panels coated good barrier as TANI increased, rate corrosion decreased. Salt spray tests indicated improved adhesion coating resistance compared neat coating.