(619ba) Introduction and Study on Electron-Beam Assisted Stabilization Process for Cost-Effective Manufacture of Carbon Fibers: Process to Bring about Wide Application of Lightweight Structural Composites for Sustainable Environment

To lower energy consumption and carbon emission in transportation is essential choice for future sustainable environment. Employing a lightweight structural composite with high mechanical properties in the structure of transportations can be thought as one of the approaches. As a reinforcing material in the composite, a carbon fiber (CF) is a promising candidate due to its high strength and modulus per unit weight. Even though the CFs have been commercialized and available in the market, the application of CFs is still limited to specific transportation such as aircraft parts due to their high manufacture cost. The wide application to common transportations such as personal vehicles will be realized by decreasing the manufacture cost of CFs.

The manufacturing process of CFs derived from polyacrylonitrile (PAN, the most common precursor polymer of CF) can generally be divided into three processing steps: 1) spinning and stretching, 2) stabilization (200~300 °C) and 3) carbonization (â?¥1000 °C). A number of experimental parameters associated in each step have been extensively optimized for the energy and time effective manufacture of the CFs. Among these three steps, the stabilization is the most crucial step as a determinant of not only high performance but also of processing cost due to lengthy heat treatment. The conventional stabilization is carried out by passing the fibers through a series of convection ovens with gradual temperature gradient (200~300 °C) for two to three hours, which is the most time and energy consuming step. As one of the methods to shorten such lengthy step with expensive energy consumption, electron beam irradiation on PAN precursor fibers has been employed prior to short thermal treatment. In conclusion, with short treatment of electron beam (200 sec), the irradiated fibers were successfully stabilized with short time of thermal treatment (30 min). In the presentation, we briefly overview the environmental impacts if the CF composites are commonly applied to transportation parts and approaches towards low manufacture cost of CF for each of manufacturing step. In particular, as one of the specific suggestions to the problem and study, the electron beam treatment for energy-effective stabilization will be explained in detail by presenting several characterizations of irradiated PAN fibers.