High-performance C/C composites derived from phthalonitrile matrix CFRP via a few cycles of vacuum-assisted impregnation-carbonization

Abstract

Novel approach of fabrication of carbon–carbon composites from carbon fiber reinforced plastics with phthalonitrile matrices was presented. Polymer composites were obtained by vacuum infusion, carbonized, and reimpregnated with following carbonization to reduce porosity of the resulting materials. The highest mechanical properties and lowest porosity were obtained when CFRP post-cured at 375 °C was taken initially. 4 cycles of impregnation-carbonization are sufficient to fabricate materials with the highest properties. Phthalonitrile resin transformations through curing, carbonization and graphitization using XRD, Raman spectroscopy, elemental analysis, FTIR and solid-state NMR were researched. TGA-MS revealed exposure of CH4, NH3, H2O, HCN, benzene and phenol gases during carbonization. Amorphous carbon materials were obtained after carbonization at 1000 °C with ID/IG = 2.38 and graphitization at 2200 °C resulted in formation of more structured carbon material with ID/IG = 0.63. Mechanical and thermal properties of the composites were determined at every step of the process.