Porous, low thickness carbon-fiber reinforced epoxy composites with excellent flexibility and superior electromagnetic radiation protection

Fiber reinforced polymers, especially carbon fiber reinforced polymers, are expected in the future to contribute more than 50% of the structural mass of an aircraft. With increasing application and experience increased attention is paid to carbon-fiber reinforced composites with improved advanced properties, such as mechanical, structural and electrical, allowing them to displace the more conventional materials, such as metal alloys. In this paper, we used the Design of experiment methodology to investigate the design and properties of newly developed unique porous carbon-fiber reinforced composites intended for electromagnetic shielding purposes. The main goal was therefore to fabricate a composite with low thickness, high permeability to air and water vapor with a satisfactory ability to shield electromagnetic fields, whereas the investigation of the influential variables of the reinforcement and the investigation of the influence of the matrix on the overall shielding efficiency of the composite belongs to the sub-objectives. Furthermore, other important properties of the composites including heat and mass transfer, mechanical and electrical properties were evaluated. A quality index evaluation approach using weighted and normalized data was implemented to choose a composite with properties, which best fits to its intended use. The highest quality index was achieved by the composite containing reinforcement with warp and weft sett 18 dm ⁻¹ using carbon tape 2 mm wide. This composite provides electromagnetic shielding 36 dB at 1.5 GHz, having high air permeability 1000 mm/s, relatively low bending rigidity of around 2.5 Nmm and thickness of only 0.37 mm.