High Scattering, Hybrid Polymer Paint System for Thermal Control

Remotely piloted aircraft (RPA) are finding expanding roles within the US Air Force and are being exposed to severe environmental conditions with increasing frequency. Due to their high value/utility in early stage operations, it is desirable to protect the RPAs from any damage or loss due to high winds, ice, and strong temperature gradients. Thermal control is particularly important for these aircraft and solar heating is typically controlled with a highly reflective/scattering white topcoat. Ideally, this coating would achieve >99% total reflection across the entire solar range (UVSWIR) while providing durable corrosion protection in a sprayable paint formulation. However, current coating formulations are unable to achieve such high total reflectance values. Chemists at Luna Innovations recently developed a class of low absorption, hybrid sulfide polymers that demonstrated unusually low absorption and high scattering across the Vis-NIR range. Combining these novel polysulfides with high scattering pigments was expected to provide unprecedented total reflectance for a spray-ready coating system, and Luna was able to demonstrate over 95% total reflectance in Phase I. The proposed Phase II effort will focus on optimizing these polysulfides and coating formulations in compliance with MIL-PRF-32239 to satisfy the RPA thermal control requirements.