Effect of total acrylic/fluorinated acrylic monomer contents on the properties of waterborne polyurethane/acrylic hybrid emulsions

Stable emulsions of waterborne poly(urethane-urea) (WBPU, soft segment content: 57 wt%, dimethylol propionic acid: 19 mol%/5.8 wt%)/n-butyl acrylate (BA)/glycidyl methacrylate (GMA)/perfluorodecyl acrylate (PFA) (weight ratio of BA/GMA/PFA: 5/3/2) hybrid materials containing 0-30 wt% of acrylate content (fluorinated acrylate content: 0-6 wt%) were successfully prepared by an emulsifier-free/solvent-free prepolymer mixing process. However, the as-polymerized hybrid emulsion containing 40 wt% of acrylic monomer content was found to be unstable, indicating that near 40 wt% in acrylic monomer content was beyond the limit of the self-emulsifying ability. By the curve fitting analysis of IR-peaks and X-ray photoelectron spectroscopy (XPS) analysis, the C-F content was found to increase with the increase in acrylate content. The average particle size of emulsion, young modulus/ yield point in stress-strain curve, hardness, thermostability, and water/methylene iodide-contact angles of the film sample increased with increasing acrylate content. However, the viscosity of emulsion, the elongation at break, water swelling and surface energy of film samples were significantly decreased with increasing acrylate content. The tensile strength of film sample decreased a little with increasing acrylate content. These results point to the strong potential of WBPU (70 wt%)/acrylate copolymer (30 wt%) hybrid as a coating material with the lowest surface energy (18.18 mN/m) and the highest contact angles (water: 111.76o, and methylene iodide: 79.95A degrees).