In order to understand the electrical and mechanical property changes which occur when graphite fibers are intercalated, it is essential that a better understanding of the properties of the fibers prior to intercalation be developed. Research aimed at elucidating the structure-property relationships in neat carbon and graphite fibers is presented. In particular, the changes with increasing heat treatment in both electronic and structural properties are discussed. The relative importance of crystallite size, three dimensional order, and the details of disordered regions between crystallites are demonstrated by analysis of: resistance versus temperature; piezoresistance; x-ray diffraction; and intercalation behavior. Crystallite size effects must be included in order to understand the electronic structure of the fibers studied here. Arguments which demonstrate the potential importance of the disordered regions between crystallites to the anamolous resistance-temperature behavior of low-modulus, high-strength fibers are presented. Three dimensional order is shown to increase continously with heat treatment. The piezoresistance of carbon and graphite fibers is discussed in terms of a simple polycrystalline model, and useful qualitative information on the parameters needed for modelling the elastic properties of these material is obtained.

Graphite intercalation compounds are a new class of electronic materials that are classified as graphite-based host guest systems. They have specific structural features based on the alternating stacking of graphite and guest intercalate sheets. The electronic structures show two-dimensional metallic properties with a large variety of features including superconductivity. They are also interesting from the point of two-dimensional magnetic systems. This book presents the synthesis, crystal structures, phase transitions, lattice dynamics, electronic structures, electron transport properties, magnetic properties, surface phenomena, and applications of graphite intercalation compounds. The applications covered include batteries, highly conductive graphite fibers, exfoliated graphite and intercalated fullerenes and nanotubes.

The research on graphite intercalation compounds often acts as a forerunner for research in other sciences. For instance, the concept of staging, which is fundamental to graphite intercalation compounds, is also relevant to surface science in connection with adsorbates on metal surfaces and to high-temperature superconducting oxide layer materials. Phonon-folding and mode-splitting effects are not only basic to graphite intercalation compounds but also to polytypical systems such as supercon ductors, superlattices, and metal and semiconductor superlattices. Charge transfer effects playa tremendously important role in many areas, and they can be most easily and fundamentally studied with intercalated graphite. This list could be augmented with many more examples. The important message, however, is that graphite inter calation compounds represent a class of materials that not only can be used for testing a variety of condensed-matter concepts, but also stimulates new ideas and approaches. This volume is the second of a two-volume set. The first volume addressed the structural and dynamical aspects of graphite intercalation compounds, together with the chemistry and intercalation of new compounds. This second volume provides an up-to-date status report from expert researchers on the transport, magnetic, elec tronic and optical properties ofthis unique class of materials. The band-structure cal culations of the various donor and acceptor compounds are discussed in depth, and detailed reviews are provided ofthe experimental verification ofthe electronic struc ture in terms of their photoemission spectra and optical properties.

There is a clear need for high-strength, lightweight composites with improved electrical conductivity. Composites fabricated from intercalated graphite fiber show promise in satisfying that need. This research focused on the chemical aspects of fiber intercalation, stability of intercalated fibers and their relation to the mechanical and electrical properties of their epoxy composites. Early work on this project helped pin down the mechanism of formation of so-called acceptor compounds of graphite as one of oxidation by election transfer to highly electrophylic species. We then established that, at least in the prototype graphite nitrate, neutral species could be removed under vacuum, and that these labile acid species must be removed before stable composites could be prepared from the intercalated fiber. In addition, we studied the kinetics of nitric acid intercalation of graphite fiber and powder and highly ordered pyrolytic graphite and offerred a proposed mechanism based on crystallite size. Epoxy composites were fabricated from graphite fiber intercalated with nitric acid.

Laminar composites were fabricated from pristine and bromine intercalated pitch based graphite fibers. It was found that laminar composites could be fabricated using either pristine or intercalated graphite fibers using standard fabrication techniques. The intercalated graphite fiber composites had electrical properties which were markedly improved over both the corresponding pitch based and polyacrylonitrile (PAN) based composites. Despite composites resistivities more than an order of magnitude lower for pitch based fiber composites, the lightning strike resistance was poorer than that of the Pan based fiber composites. This leads to the conclusion that the mechanical properties of the pitch fibers are more important than electrical or thermal properties in determining the lightning strike resistance. Based on indicated lightning strike tolerance for high elongation to failure materials, the use of vapor grown, rather than pitch based graphite fibers appears promising. Gaier, James R. and Slabe, Melissa E. and Brink, Norman O. Glenn Research Center NASA-TM-104507, E-6370, NAS 1.15:104507 RTOP 506-41-41...

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

'The field of carbon materials is huge and often difficult to comprehend, but this book is easy to read and methodically covers the subject, including presenting materials properties and performance data with clear illustrations and graphs. References include relevant older and up-to-date sources of information. The book is tutorial style in nature and is an excellent resource for senior undergraduates, graduate students, researchers, and anyone who wants to learn more about carbon and incorporate carbon materials into new applications.'MRS BulletinElemental carbon materials take numerous forms including graphite, carbon fiber, carbon nanotube, graphene, carbon black, activated carbon, fullerene and diamond. These forms differ greatly in the structure, properties, fabrication method, and applications. The applications of these carbon forms include electronic, electromagnetic, electrochemical, environmental and biomedical applications. Carbon materials are a subject of intense research, with strong relevance to both science and technology.This book provides a tutorial-style and up-to-date coverage of the carbon forms. In addition to an introductory chapter on carbon materials, the book includes chapters on graphite, graphene, carbon black, activated carbon, carbon fibers, and carbon nanofibers/nanotubes. For example, the chapter on graphite covers various materials in the graphite family, including polycrystalline graphite, pyrolytic graphite, turbostratic carbon, intercalated graphite, graphite oxide, exfoliated graphite and flexible graphite, in addition to their electronic and mechanical properties.This book is suitable for use as a textbook for undergraduate and graduate students in science and engineering, and as a reference book for professionals. It is dedicated to the memory of the author's PhD thesis advisor, Professor M S Dresselhaus (1930-2017) of Massachusetts Institute of Technology.