Electrical conductivity study of carbon nanotube yarns, 3-D hybrid braids and their composites

Long continuous yarns consisting solely of carbon nanotubes may be the future of specialty composites requiring unique multi-functional properties. Many of such yarns were incorporated in a hybrid composite here, to demonstrate for the first time, their effect on increasing the electrical conductivity of an otherwise insulating composite. Six-ply nanotube yarns produced by University of Texas at Dallas were used as a raw material in this study. Thirty-six ends of such yarn were utilized in a 3-D braiding process along with nine axial bundles of glass fibers. The experimental study of the electrical conductivity of the produced nanotube yarns, 3-D braids and composites made thereof is described; the results for different tested materials are mutually compared and discussed. Some non-trivial effects attributed to the complex multi-level hierarchy and nano-scale building blocks of the studied materials are revealed. Special attention is paid to a proper interpretation of the obtained experimental results, because the tested materials represent complex discrete networks of numerous electrically conductive elements.