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Powder coatings are a promising, solvent-free alternative to traditional liquid coatings due to the superior corrosion protection they provide. This study investigates the effects of incorporating montmorillonite-based nanoclay additives with different particle sizes into polyester/triglycidyl isocyanurate (polyester/TGIC) powder coatings. The objective is to enhance the corrosion-protective function of the coatings while addressing the limitations of commonly employed epoxy-based coating systems that exhibit inferior UV resistance. The anti-corrosive and surface qualities of the coatings were evaluated via neutral salt spray tests, electrochemical measurements, and surface analytical techniques. Results show that the nanoclay with a larger particle size of 18.38 µm (D50, V) exhibits a better barrier effect at a lower dosage of 4%, while a high dosage leads to severe defects in the coating film. Interestingly, the coating capacitance is found, via electrochemical impedance spectroscopy, to decrease during the immersion test, indicating a self-repairing capability of the nanoclay, arising from its swelling and expansion. Neutral salt spray tests suggest an optimal nanoclay dosage of 2%, with the smaller particle size (8.64 µm, D50, V) nanoclay providing protection for 1.5 times as many salt spray hours as the nanoclay with a larger particle size. Overall, incorporating montmorillonite-based nanoclay additives is suggested to be a cost-effective approach for significantly enhancing the anti-corrosive function of powder coatings, expanding their application to outdoor environments. [ABSTRACT FROM AUTHOR]

Aluminum trihydrate (ATH) is one of the most widely used fillers in solvent-borne coatings and polymer industries. To investigate its performance in powder coatings, four different pigment to binder ratios (P/B) were used in respect to different ATH concentrations in four most widely used resin systems (epoxy, epoxy-polyester, polyurethane and polyester). The angle of repose (AOR) and specific gravity of powder paints increase accordingly with ATH concentration. The mechanical properties, corrosion and UV resistance performances of coating films are enhanced or only slightly decreased with the addition of ATH. Pencil scratch hardness increase significantly with the increase of ATH content. Impact resistance decreases within 5% of the initial resistance at the maximum ATH loading. There is a slightly decrease in corrosion resistance performances of less than 2 mm of failure at scribe in all formulations. The incorporation of ATH has slight effect on the UV resistance performance of all the samples. Moreover, the matting effect of ATH is observed for all the resin systems, especially epoxy, with the specular gloss decreasing more than 70% at P/B of 0.75. [ABSTRACT FROM AUTHOR]