Self-stratified bio-based coatings: Formulation and elucidation of critical parameters governing stratification

Self-stratification is an innovative one-step process used to design multi-functional coatings gathering simultaneously in a one-pot formulation the primer, intermediate layer and top coat properties. Many self-stratifying contain oil-based epoxy resins but literature scarce development of “greener” solutions. In this work, silicone bio-based were dissolved various solvent blends, applied on composite substrate cured under different conditions obtain stratified coatings. To reach perfect stratification, influence parameters including (i) surface tension polarity resins, (ii) solvents volatility, (iii) curing temperature (iv) reactivity epoxy/amine reaction was studied by systematic approach. accordance with literature, it demonstrated that large difference energy favors separation. The volatility blend also shown be key factor stratification process. However, predominant parameter, rarely taken into account, temperature, which impacts cross-linking resin. increase molecular weight (MW) due incompatibility between increasing MW resins. Thus, optimization allowed perfectly epoxy/silicone mechanism film elucidated thanks in-situ analyses.