Heat-Shielding Nanobrick Wall for Carbon Fiber-Reinforced Polymer Composites

Owing to their excellent mechanical properties, carbon fiber reinforced polymer (CFRP) composites have a broad spectrum of applications in aerospace, civil engineering, automotive, and numerous industrial fields. Despite their many advantages, the inherent lack of thermal stability of the polymer matrix results in the loss of the composite's mechanical properties when exposed to elevated temperatures. In an effort to provide thermal protection, a multilayer film composed of tris(hydroxymethyl)-aminomethane (THAM)-buffered polyethylenimine (PEI) and vermiculite (VMT) clay was deposited on CFRP composites via layer-by-layer assembly. When subjected to the flame from a butane torch and mechanical loading, the polymer-clay nanobrick wall provides substantial thermal insulation, decreasing the temperature on the backside of the CFRP composites by as much as 100 degrees C. The PEI-THAM/VMT coating also helps to maintain the storage modulus of the composite and offers significant protection from oxidative degradation, as confirmed by dynamic mechanical analysis and X-ray photoelectron spectroscopy. The performance of this polymer-clay multilayer film provides excellent thermal barrier that can be used to protect advanced composite materials from extreme heat.