Novel carbon fibers synthesis, plasma functionalization, and application to polymer composites

PAN copolymers were synthesized via a novel technique, atom transfer radical polymerization (AMP), with the activator generated by electron transfer method (AGET). Carbon fibers (CF) were synthesized at low carbonization temperatures from the novel PAN precursor. Plasma treatment in an oxygen environment at a low pressure of 40 Pa was carried out for 5 minutes on the CF at 100 and 200 W plasma power. The morphology and structure of the CF changed after plasma functionalization, as evident from SEM analysis and Raman spectroscopy. The formation of functional groups like alcohols, carbonyl, and carboxylic on the surface of CF was confirmed with the aid of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The wetting test confirmed the higher adhesion of the plasma functionalized CF with the epoxy matrix. Single fiber strength test revealed that plasma functionalized CF retained around 98% of their original tensile strength. Composites were fabricated from the pristine, and the plasma functionalized CF in 1 and 3% by weight with epoxy matrix. The surface-modified CF composites depicted improved tensile (23.4%), tribology (33.62%), and surface hardness (11.4%) properties compared to the composites fabricated from pristine CF.