Superior barrier, hydrophobic, and mechanical properties of the epoxy nanocomposite containing mixed metal oxides

Abstract

Newly synthesized 3-amino-1,2,4-triazole-5-thiol (ATT) functionalized Al₂O₃-ZnO nanoparticles were added to epoxy resin (EP). The anticorrosion properties of newly synthesised formulations like EP/Al₂O₃-ZnO and EP-ATT/Al₂O₃-ZnO nanocomposite coated steel samples were investigated electrochemically using scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS). In natural seawater, EIS experiments indicated outstanding protective behaviour for the EP-ATT/Al O₃-ZnO coated steel. The EP-ATT/Al₂O₃-ZnO nanocomposite coating resistance was reported to be 2110.44 kΩ·cm², whereas EP/Al₂O₃-ZnO coating (1730.45 kΩ·cm²) and pure epoxy coating (61.21 kΩ·cm²) had lesser coating resistance. The coating resistance of EP-ATT/Al₂O₃-ZnO nanocomposite was found to be more than 34% greater than that of PU coating. The measured current by SECM analysis over the EP-ATT/Al₂O₃-ZnO nanocomposite coating was very low (1.6 nA) compared to EP/Al₂O₃-ZnO (3.7 nA) and pure epoxy coated steel (5.9 nA). The surface morphological studies of the coated steel by SEM/EDX analysis and X-ray diffraction (XRD) analysis revealed that the Al₂O₃-ZnO nanoparticles were enriched at the corrosion products which prevented corrosion initiation processes. The peel strength of the EP-ATT/Al₂O₃-ZnO nanocomposite film was found to be 982 ± 13 N/cm when the concentration of ATT/Al₂O₃-ZnO nanoparticles was 2 wt.%. Moreover, the resultant EP-ATT/Al₂O₃-ZnO formulation exhibited an excellent hydrophobic behaviour (WCA: 117°). Therefore, it was concluded from the electrochemical and mechanical investigation that the newly synthesized EP-ATT/Al₂O₃-ZnO nanocomposite provided an excellent barrier and mechanical properties due to the addition of ATT/Al₂O₃-ZnO nanoparticles to the epoxy resin which prevented the degradation of materials and helped to prolong the life of the coated steel.

HIGHLIGHTS

• Electrochemical studies revealed excellent coating resistance and a decreased corrosion current density for the EP-ATT/Al₂O₃-ZnO coated steel in natural seawater

• It was found that the coating resistance of EP-ATT/Al₂O₃-ZnO nanocomposite was over 34% higher than that of the epoxy coating.

• The EP-ATT/Al₂O₃-ZnO coating retarded the propagation of aggressive ions to the coating/steel interface.

• The reinforcement of ATT/Al₂O₃-ZnO nanoparticles in the epoxy coating exhibited a smooth microstructure producing superior corrosion protection and excellent hydrophobic and dynamic mechanical properties.

• The addition of ATT/Al₂O₃-ZnO nanoparticles to the epoxy prevented the degradation of materials and helped to prolong the life of the coated steel.

Keywords:

• Al₂O₃-ZnO nanoparticle
• functional nanocomposite coatings
• dynamic mechanical analysis
• electrochemical techniques
• corrosion
• adhesion strength

Disclosure statement

No potential conflict of interest was reported by the author.