Influence of the chemical composition and formulation of fluorinated epoxy resin on its surface characteristics

The incorporation of perfluorononanoic acid into epoxy resins was investigated in order to prepare a material with low adhesion properties (low free surface energies comprised between 15 and 26 mJ m(-2)). A laboratory grade tetrafunctional epoxy resin was fluorinated by direct reaction with the perfluorinated carboxylic acid. A bifunctional epoxy resin fluorinated beforehand was also added to the tetrafunctional epoxy resin. The fluorinated resins were analyzed by FTIR spectroscopy. Dynamic DSC experiments were performed for the resins in presence of a stoichiometric quantity of the curing agent. Results were compared with those obtained with a commercial grade of the fluorinated tetrafunctional resin. Finally, the influence of the curing cycle was studied and optimized. The surface properties of the cured resins were then characterized in terms of free surface energy with contact angle measurements.