Ti3C2MXene/polyaniline/montmorillonite nanostructures toward solvent-free powder coatings with enhanced corrosion resistance and mechanical properties

Abstract

Solvent-free powdercoatings have become very popular in the coatingindustry in replacing conventional liquid coatings for the last decades.However, poor adhesion of powder coatings to the substrate and microporesinevitably created during the curing process of coatings lead to localizedcorrosion and reduced mechanical resistance. For this purpose, Ti3C2 MXene/polyaniline (PANI)/montmorillonite (MMT)nanocomposites with superior conductivity and adhesion capabilitieswere incorporated into the eco-friendly powder coating. The as-synthesizednanocomposites were analyzed using various techniques such as Fouriertransform infrared spectroscopy, X-ray diffraction, X-ray photoelectronspectroscopy, high-resolution transmission electron microscopy, field-emissionscanning electron microscopy, and Raman spectroscopy. To evaluatethe effectiveness of the powder coating in preventing corrosion ona mild steel substrate, two methods were employed: potentiodynamicpolarization and electrochemical impedance spectroscopy. The electrochemicaltests revealed that an excellent dispersion of 1.5 wt % Ti3C2 MXene/PANI/MMT nanosheets in a polyester/epoxy powdercoating resulted in superior anti-corrosion performance (4.8 x10(6) omega) after 42 days of immersion in 3.5 wt % NaClas compared to blank samples (7.2 x 10(2) omega).According to Tafel analysis, the corrosion potential of the optimalsample is -0.062 V, which is more positive than that of thepristine powder coating (-0.83 V). The polarization resistance(R (p)) and corrosion current (i (corr)) of the optimal sample are determined to be 3.39x 10(6) omega center dot cm(2) and 7.69 x10(-9) A center dot cm(-2), respectively.Moreover, the optimal sample marginally increased the hardness (229.42MPa) compared to the pure sample (152.68 MPa) due to the synergisticeffect of Ti3C2 MXene and flake-like MMT nanoparticles,which results in an improvement in the mechanical strength of powdercoatings. Additionally, the presence of PANI caused further crosslinkingand modulation of the electrical conductivity of the produced nanocomposites.The present study proposes a practical method to enhance the mechanicaland shielding properties of solvent-free powder coatings, making themsuitable for use in various real-world applications, including commercial,medical, and household sectors.