Effect of microstructure of fluorinated acrylic coatings on UV degradation testing

This paper presents research results on the relationships between the microstructure and the performance/weatherability of fluoropolymer/acrylic coatings. We studied fluoropolymer/acrylic blends of identical composition, prepared as films using three different methods: 2-stage emulsion polymerization followed by latex film formation; cold-blending (physically mixing) acrylic and fluoropolymer latex dispersions followed by latex film formation; and solution casting using an organic solvent. We investigated the effects of the mixing method, and the level of acrylic in the blend on the microstructure/morphology and on the durability-related physical properties of the fluoropolymer/acrylic films. Small angle neutron scattering was performed to determine the microstructure/morphology of fluoropolymer-rich micro-domains in the coatings prepared using these three methods. The physical properties tested included the glass transition temperature, the crystallinity fraction, and the tensile strength. The mass loss rates observed during UV exposure testing correlate with the final microstructures of the films.