ABSTRACT
Carbon fibers, first used as light bulb filaments in 1879, trace their history in the early 1950s and 60s during the requirement of the aerospace industry for lightweight materials. This led to the development of high strength and high stiffness continuous length of carbon fibers with diameter ranging from 7 to 10 μm as reinforcement in polymer composites. Following this realization there were a number of relatively successful attempts to prepare carbon fibers from different precursors, especially those from Roger Bacon at Union Carbide using viscose rayon in 1957 [1], Shindo in Japan using polyacrylonitrile (PAN) in 1961 [2], and of Ōtani, also in Japan in the year 1965, using an isotropic pitch [3]. In most cases these filaments are derived from organic precursors by spinning them into polymer fibers followed by thermal oxidative stabilization at 200°C-300°C and carbonization at 1000°C in an inert atmosphere. Further heat treatment up to temperatures of ~3000°C helped them attain well-oriented graphitic structure with larger crystallite size and high stiffness in the process called graphitization.
