Curing-induced internal stress in epoxy coatings: Effects of epoxy binder, curing agent, filler, initial solvent concentration, curing temperature, and relative humidity

Curing-induced internal stresses in epoxy coatings are highly influenced by the type and concentration of product ingredients conditions applied. In this work, effects on curing-dependent modulus stress development epoxy/crosslinker chemistry, curing temperature, relative humidity, filler conditions, initial solvent concentration, studied. Analytical methods include attenuated total reflection-Fourier transform infrared (ATR-FTIR) technique, dynamic mechanical thermal analysis (DMTA), a 3D optical profilometer, beam deflection. An elevated temperature (35 or 45 °C) resulted smaller elastic and, despite an accelerated reaction higher final reactant conversion, only slight increase, around 0.2 MPa, average stress. increased humidity (from 35 to 60 %), also less volumetric shrinkage However, at 90 % stress, due enhanced was than observed RH. The presence either BaSO4 CaCO3 formulation reduced conversion shrinkage, but When from zero 20 vol%, although extra introduced evaporation, 0.72 0.85, while decreased 1.25 0.6 MPa. Guidelines for how optimize coating formulations avoid presented.