Structure and properties of carbon fibers produced using microwave-assisted plasma technology, part 1

Commercial grade carbon fibers are currently produced by thermal pyrolysis of a Polyacrylonitrile (PAN) precursor. The most significant cost factors in carbon fiber production are the high cost of precursors, high capital equipment costs and the energy costs. The Department of Energy is supporting development efforts to reduce costs in both precursor production and conversion areas. Oak Ridge National Laboratory (ORNL) has been developing new technologies to lower the cost of manufacturing of PAN based carbon fibers. Microwave-assisted plasma (MAP) technology is a novel process recently developed at ORNL specifically to meet this technological requirement. The properties and structure of several PAN-precursor carbon fiber tows, MAP processed at different line speeds, were evaluated. The results indicate that the MAP carbonization process is a viable technical alternative to conventional oven processing. MAP technology produces carbon fibers with physical and mechanical properties that are comparable to those of conventional, inexpensive commercial grade fibers. The morphology of the MAP carbon fibers manufactured with different processing parameters was evaluated using wide-angle X-ray diffraction techniques. The results indicate that the MAP fibers generally exhibit similar morphological characteristics compared to current commercial grade, PAN-based, carbon fiber produced by conventional means.