Incorporation of different cerium-modified montmorillonites for development of epoxy nanostructured powder coatings

This study has as objective to develop an epoxy-based powder paint based on a standard commercial powder paint formulation with the addition of different contents (2, 4, and 8% wt.) and types of montmorillonites (MMT-Na ⁺ , OMMT-15A, OMMT-30B), modified with cerium IV nitrate and ammonia. The incorporation of modified clays (MMT-NaCe, OMMT-15ACe, and OMMT-30BCe) on epoxy-based powder paints was conducted in a co-rotating twin-screw extruder in the molten state to produce powder paints where physical, chemical, morphological, structural, and anticorrosive properties were evaluated. The addition of various clay types and contents only produced nanocomposites with a structure that was primarily exfoliated. Occasionally, all nanocomposites showed a decrease of the thermal stability (from 426°C to 398°C, in the case of OMMT-15A) and in the heat of reaction (from 115.4 J.g ^-1 to 40.8 J.g ^-1 , in the case of OMMT-30B) which interfered with the epoxy resin’s reactivity. The surface irregularity of the power paint formulations was found to increase with an increase in the contact angle (from 78.1° to 87°, for MOOT-15A). Subcutaneous migration carried out following exposure to salt spray and electrochemical impedance spectroscopy analysis revealed an improvement (according to Niquist diagrams) in anticorrosive performance in comparison to the matrix.