Carbon-carbon composites for improving fire retardancy and electrical and thermal conductivities

Abstract

Carbon-carbon fiber composites have been developed and used in various industries, such as transportation, energy, defense, and infrastructure because of their excellent chemical stability, high temperature resistance, high electrical and thermal conductivities, low coefficient of thermal expansion, and high modulus of elasticity. The aim of this study is to synthesize and characterize the carbon-carbon fiber composites in desired shapes (2D or 3D) for fire retardancy, lightning strike, EMI shielding, and other high temperature aerospace and space applications. Polyacrylonitrile (PAN) powder was dissolved in DMF solution, and carbon fibers with desired concentrations (10-90wt%) were immersed into this solution prior to the evaporation. Vacuuming at 25 in.Hg during the evaporation and drying processes has reduced the air and voids in the composite structures. Thin layers of PAN/woven carbon fiber systems were then stabilized at 270°C for 60 minutes in air, and then carbonized at 650-850°C for 120 minutes in presence of Ar (Argon gas) to receive carbon-carbon composites in desired sizes and shapes. Various characterization tests have been conducted on the prepared samples, including tensile, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), laser confocal microscope, UL 94 fire retardancy tests, Fourier transform infrared spectroscopy (FTIR), electrical and thermal conductivity and water contact angle tests. The test results indicated that the prepared samples have excellent chemical, mechanical and thermal properties, which may be useful for numerous aerospace industries.