Effect of addition of clay minerals on the properties of epoxy/polyester powder coatings

Abstract Powder coatings have been used for coating metal substrates in industrial applications. The incorporation of nanofillers as muscovite mica and montmorillonite (MMT) can improve the properties of the coatings. The objective of this study is to develop, apply and characterize a hybrid powder coating (30% epoxy/70% polyester) adding nanofillers in concentrations of 2, 4 and 6 phr separately in a twin screw extruder. The characterization of the coatings was performed by thermal, mechanical and chemical analysis. The incorporation of clay into the polymer increased the surface roughness resulting in a diffuse reflection of incident light and on a gloss reduction. The muscovite mica presented a lamellar structure, constituted by a set of overlapping parallel plates. The morphology analysis showed that the MMT presented irregular agglomerates resulting in inferior mechanical properties to coatings with muscovite mica. In the salt spray test, all samples showed high corrosion protection, around 850 hours.

摘要：粉末涂料已广泛应用于工业场景中的金属基材涂装。向涂料体系中掺入白云母（muscovite mica）与蒙脱土（montmorillonite, MMT）两类纳米填料（nanofillers），可有效改善涂层的综合性能。本研究旨在开发、施工并表征一款30%环氧树脂/70%聚酯树脂的混合型粉末涂料：分别以2、4、6 phr（每百份树脂质量份）的浓度向体系中添加纳米填料，涂层制备过程通过双螺杆挤出机（twin screw extruder）完成。本研究通过热学、力学与化学分析对涂层进行表征。向聚合物基体中添加黏土类填料后，涂层表面粗糙度升高，导致入射光发生漫反射，进而降低了涂层光泽度。白云母呈现出层状结构，由多片相互叠合的平行薄板构成。形貌分析结果显示，蒙脱土易形成不规则团聚体，因此添加蒙脱土的涂层力学性能劣于添加白云母的涂层。盐雾试验结果表明，所有试样均表现出优异的防腐蚀性能，防护时长可达约850小时。