Corn oil based poly(ether amide urethane) coating material—Synthesis, characterization and coating properties

•Poly(ether amide urethane) resin was utilized as corrosion protective and environmental friendly coating materials.•The approach provides an alternative method to utilize corn oil.•Poly(ether amide urethane) as good coating material cured at room temperature.•The coatings showed good scratch hardness, flexibility, corrosion performance and safe use up to 250 °C.

Polyetheramide (CPETA) resin was synthesized from N,N-bis (2-hydroxy ethyl) corn oil fatty amide (HECFA) and catechol through condensation polymerization. CPETA was further cured with isophorone diisocyanate (IPDI) in different weight percentage (20, 25, 30, 35, 40 wt.%) to obtain poly(ether amide urethane) (CPETAU). The structural elucidation of HECFA, CPETA and CPETAU was carried out by FT-IR, 1H NMR and 13C NMR spectroscopic techniques. Physico-chemical and physico-mechanical properties of these resins were investigated by standard methods. Thermal behavior was assessed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The corrosion resistance performance of CPETAU coatings on mild steel strips was investigated by potentiodynamic polarization studies in different corrosive media (3.5 wt.% HCl, 5.0 wt.% NaCl, tap water) at room temperature. Amongst all the compositions, CPETAU coatings showed good scratch hardness (2.20 kg), impact resistance (150 lb/inch), gloss with corrosion rate obtained as 1.377 × 10−2 (mm/year) and 2.359 × 10−3 (mm/year) in 3.5 wt.% HCl and 5.0 wt.% NaCl solution, respectively. CPETAU coatings can be safely used up to 250 °C.

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