ABSTRACT
Carbon fibers are one of the most famous kinds of carbonaceous materials due to their special characteristics such as high conductivity, strength and modulus [1, 2]. They are typically produced either by pyrolyzing fibers spun from an organic precursor (e.g., Polyacrylonitrile (PAN), polyimide, mesophase pitch,…) or by chemical vapor decomposition (CVD) [3 4]. Since the performance of carbon fiber composites highly depends on its precursor and the desired precursor should have high carbon content, high molecular weight and also high degree of molecular orientations, PAN based carbon fiber seems to satisfy all of these expectations [2, 5-7]. PAN based carbon nanofibers are more common because they are low-cost, continuous, and easy to be aligned and assembled. They also possess high degrees of macromolecular orientations induced by the high stretching ratios (up to 105) under the electrical force [8]. Due to their high mechanical, thermal and electrical performances PAN based carbon nanofibers can be applied promisingly in making super-capacitors, composites, etc. [9].
