Core structure of vapor grown carbon fibers and morphology dependence of tensile strength

Vapor grown carbon fibers (VGCFs) grown via a liquid pulse injection technique mostly have a turbostratic structure with a smooth surface (ca. 90%). The rest are connected or fused fibers, and fibers with spheroidal grains on their surfaces. It was clarified by TEM observation that the central core of the VGCFs whose diameter is 0.2-0.5 mum has an amorphous structure and is surrounded by graphitic sheets. Graphite layers with polygonal plates were found to be contained among circular graphite layers. The tensile strengths of individual fibers depend on their morphologies and are in the range from 0.6 to 3.7 GPa. (C) 2002 Elsevier Science Ltd. All rights reserved.