COLLABORATIVE RESEARCH AND DEVELOPMENT CONTRACT (CR&D). Task Order 0072: Minority Leaders Nanocomposite Researcher
Abstract
This research in support of the Air Force Research Laboratory Materials and Manufacturing Directorate was conducted from 1 May 2007 through 1 May 2008. This research on nanocomposites in support of the Minority Leaders Nanaocomposite Program currently in progress at AFRL/RXBC. This research encompassed processing nanomaterials with various functional groups onto composites and measuring improvements in mechanical, electrical, and thermal properties. Characterization in the nanoscale was performed using AFM, SEM, and TEM. Although it is well-acknowledged that carbon fibers possess excellent thermal conductivity (TC), direct measurement of thermal conductivity of individual carbon fibers under steady-state heat flow conditions is very difficult, and only limited studies have reported such TC values. These TC values have been correlated with electrical conductivity (EC) values, and often these TC-EC correlations are used in conjunction with EC measurements to indirectly estimate TC values. Unsteady-state heat transport phenomenon has also been utilized to obtain thermal diffusivity values, from which TC values can be calculated. The laser-flash technique was proposed a number of years ago, and has developed into a standard technique for homogeneous bulk materials. It is efficient and offers rapid measurement times (from milliseconds to a few seconds). It requires only small sample dimensions, and analysis of multi-layer samples is possible. Here we report on longitudinal TC measurements on various pitch- and PAN-based carbon fibers from laser-flash measurements on their composites. Because carbon-fiber composites are highly anisotropic and non-homogeneous, various limitations of the experimental technique and accompanying analysis are discussed, and suggestions for improvements are made.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2008
- Accession Number
- ADA530656
Entities
People
- Merlin Theodore
Organizations
- Universal Technology Corporation (United States)