Effects of MIL-R-81294 Paint Stripper on AS/3501-6 Graphite/Epoxy Composite Systems

摘要

The use of resin matrix composites for structural applications on naval aircraft has dramatically increased over the past decade. Nine percent of the F-18 Hornet is AS/3501-6 graphite/epoxy composite material. This composite material is predominantly surface structure and is coated with the standard paint scheme (MIL-P-23777 epoxy primer and MIL-C-83286 polyurethane topcoat). During general aircraft rework operations, the coating system of an aircraft is chemically stripped, which would result in the case of the F-18 to exposure of composite material to paint stripper. Previous studies have shown that the standard paint stripper MIL-R-81294 has an adverse effect on the epoxy matrix of these composite systems under total immersion exposure conditions. NAVAIRDEVCEN was tasked to evaluate the effects of MIL-R-81294 paint stripper on AS/3501-6 graphite/epoxy composites under simulated rework conditions. Results of this study show that MIL-R-81294 causes a statistically significant decrease in the physical properties of AS/3501-6 composite materials under simulated rework conditions. This deleterious effect was concentrated at the composite surface directly exposed to the paint stripper. AS/3501-6 graphite/epoxy composite structures should not be exposed to MIL-R-81294 paint stripper. (Author)