Interfacial, electrical, and mechanical properties of MWCNT in polyurethane nanocomposite coating via 2D electrical resistance mapping for aircraft topcoat

Abstract

Interfacial, electrical, and mechanical properties of polyurethane (PU)-type aircraft topcoat layers for LSP (Lightning Strike Protection) was evaluated by 2-D electrical resistance (ER) mapping with different oxidation times. Multi-wall carbon nanotubes (MWCNT) were treated using hydrogen peroxide to improve dispersion. Mechanical property of MWCNT/PU topcoat was determined via thin film tensile test, and oxidation degree was determined using TGA and EDS. Static contact angle measurements were used to evaluate work of adhesion between MWCNT and PU coating layer. Interfacial adhesion between MWCNT and PU coating layer was obtained via pull-out test and both results were consistent with different MWCNT oxidation times. Electrical properties of MWCNT/PU topcoats were evaluated by surface ER. Surface ER was the lowest at 5 days oxidation times. Higher tensile strength of MWCNT/PU topcoat could contribute to higher interfacial adhesion. Visualization was used to determine MWCNT dispersion and verified successfully using the color variation of 2D ER mapping.