Conductive Polymers as Drop in Additives for Coatings and Composites

V. Hrechka
PolyDrop LLC,
United States

Keywords: electrostatic charge dissipation, conductive plastics, conductive coatings

Summary:

An emergent core challenge for composite based fuselages is to dissipate electric charge, a problem previously resolved by the natural high conductivity of metal. Electrostatic charge build up is a severe problem in aircraft as it can interfere with sensitive electronics necessary for navigation. Current methods focus on adding carbon black pigment into the coating primers to solve electrostatic charge dissipation (ESD) issues in exterior and interior designs. We present a novel approach for effective charge dissipation that reduces weight and thereby fuel consumption. Our approach uses conductive conjugated polymers as drop-in additives to existing aircraft paint primers and composites. Conjugated organic polymers have resonating π-π bonds that can create an effective mechanism for charge transfer. Conjugated polymer materials have significantly lower densities than carbon black based coatings and, due to their self-assembling properties and unique packing structures, require a very low weight percent of additive (1 to 5 wt% ) for polymers to achieve adequate electronic conductivity. Typical carbon black particle loadings exceed 30 wt%. This is tremendously advantageous for weight reduction as well as the durability and adhesion of the paint. As an added benefit, the use of low polymer loadings means the properties of the primer remain largely intact. This results in minimal capital investment for adoption of this product into the carbon fiber assembly line since no new equipment will be needed. This presentation outlines the conductive and mechanical properties of polyurethane, epoxy, siloxane solvent and water-based paints with conjugated polymer additive that have been recently developed by PolyDrop. It shows major benefits in comparison with existing conductive coatings for ESD management at a price comparable to carbon black.