Modified Bentonite Clay in UV-Curable Coating Applications

Abstract

Modified bentonite clay was prepared by cationic exchange between the Na⁺ ions of montmorillonite in bentonite clay and two types of alkyl amines; hexadecylamine (primary amine) and hexadecyl trimethyl amine (tertiary amine). From the XRD analysis it was found that the primary amine-modified bentonite clay provided a greater inter-layer spacing than that with the tertiary amine-modified bentonite clay, although both were significantly higher when compared to the unmodified bentonite clay. The modified clay intercalated structure was then incorporated into a UV-curable coating formulation using epoxidized linseed oil acrylate as an oligomer to form a polymer clay nanocomposite. Energy consumption in the curing process and the physical properties of the cured films were studied as a function of the amount of modified clay incorporated into the coating formulations. The energy consumption in the curing process increased and the hardness and flexibility of the cured films also improved.