Hydrophobic Waterborne Epoxy Coating Modified by Low Concentrations of Fluorinated Reactive Modifier

Abstract

Fluorinated (meth) acrylate oligomer modified epoxy resin (PHFBMA-DGEBA) and polyether-modified epoxy resin (MPEG-DGEBA) were successfully synthesized and used as reactive modifier and emulsifier for epoxy resins, respectively. GPC, FTIR and 1H NMR were employed to verify the synthesis. The influence of both the concentration and the molecular weight of PHFBMA-DGEBA on the properties of waterborne epoxy resin coatings was investigated. Surface energy and surface composition were probed by contact angle measurements and X-ray photoelectron spectroscopy (XPS), which strongly confirmed the enrichment of fluorinate atoms on the surface. The surface energy of waterborne epoxy coating was decreased from 44.46 mN/m to 23.20 mN/m by adding just 0.09 wt% PHFBMADGEBA-2, indicating its high effectiveness in improving the surface hydrophobicity. Moreover, the physical properties of waterborne epoxy coatings prepared with different concentration and molecular weight of fluorinated reactive modifier, such as water absorption, Shore D hardness, adhesion, thermal properties and optical transmittance, were also analyzed in detail. Taken together, the waterborne epoxy coatings prepared with low concentrations of reactive modifier are economical and have great potential in large scale industry applications.