High Performance Flat Coatings Through Compatibilized Immiscible Polymer Blends

摘要

A new approach to high performance ultra low gloss aircraft coating systems is described based on compatibilized immiscible blends of two polyols that differ significantly in surface energy. Extensive characterization measurements show the performance of the polymer alloy systems surpasses existing benchmark polyurethane and fluoropolymer topcoat systems in hardness, chemical resistance, fluid resistance, abrasion resistance, and cleanability. The superior performance in screening tests is attributed to a favorable synergism between the parent homopolymers that is enabled by the stress bearing interface and morphology peculiar to an alloy. A method is explored for connecting a standard coating screening test to the more fundamental linear response coefficients measured in thin film dynamic mechanical analysis (DMA). An extension is proposed aimed at utilizing the thermodynamic drive arising from the difference in component surface energies to assemble pigments in threadlike fashion through one polymer phase to prescribe effective medium optical properties at minimal pigment loading.