Graphite Nanoplatelets Films as Multifunctional Protective Layer in Kevlar/Nomex Sandwich Composites

Abstract

In the aerospace sector, structural and non-structural components are usually subjected to a wide range of environmental conditions. Although lightweight, the use of composite parts for these applications is restricted, due to their poor performance in severe environmental conditions. Specifically, moisture can seriously damage the materials' performance, reducing their mechan-ical, thermal, electrical, and physical properties as well as the service time. A strategy to improve the materials’ resistance in humid environments is the use of protective lightweight barrier coatings to reduce the diffusion of gases and/or liquids in composites. Nanolamellar nanocom-posite characterized by the high in-plane orientation of nanoplatelets effectively works as barrier structures by generating tortuous paths for molecule diffusion. In this work, the effectiveness of protection against water uptake of nanocomposites reinforced with Graphite NanoPlatelets (GNPs) at high filler content (70, 80 and 90%wt) for Kevlar sandwich panels of a nacelle engine of an ATR42 aircraft has been investigated. Moisture uptake and Ground Air Ground (GAG) tests were carried out in an environmental chamber to reproduce temperature and relative humidity profiles representative of a real-scale application for a regional aircraft composite part. The high filler content of the graphene films ensures a high level of tortuosity by delaying and reducing moisture absorption by –71% compared to the unprotected panel, showing good barrier properties.