Carbon Fibers from Polyethylene-Based Precursors

Polyethylene fibers are attractive as carbon fiber precursors due to their high carbon content and ease of manufacture. Also, highly ordered and oriented fibers with extraordinary physical and mechanical properties are available today. However, being thermoplastic fibers, they soften or melt at a fairly low temperature, losing their fiber form. These precursors have to be stabilized by introducing cross links in them so that they can withstand the higher temperatures of carbonization. Heating in a sulfuric acid bath was investigated as a possible means of stabilizing these fibers. The process of stabilization was studied using several characterization techniques, such as thermal analyses (DSC and TGA), color change, tensile properties, X-ray diffraction and electron microscopy. The fibers had a tendency to shrink to a great extent and the tension had a major role during the process of sulfonation. Some of the stabilized fibers were carbonized and their properties were evaluated