Non-Metallic Conductive Material for ESD/EMI Applications

Ultra-light weight, highly conductive carbon nanotube sheets that can be bonded to graphite composites while also conducting in the GHz region have potential to broadly improve EMI/ESD systems. These materials have additional applications including: EMI cable shielding, EMI/EMP electronics protection, preventing unwanted EMI emissions, highly conductive ground planes, and ESD layers. This proposal describes the continued development of very large, carbon nanotube sheets and panels that are CTE matched to graphite epoxy, nickel free, and exhibit excellent insertion loss in the 1 to 20 GHz region. The phase one program demonstrated that large nanotube rollstock could be manufactured and processed on commercial pre-preg equipment, using both BMI and toughened epoxy resins, and that the prepregs could subsequently be successfully fabricated into composites. This phase two program will bring large area nanotube materials to the pre-commercialization stage with the major milestone tasks being: (1) Optimization with required resin systems, including resin content, and repair/fairing indicator pigmentation (2) Material certification properties testing , performance consistency, abrasive/corrosion environmental challenge testing, (3) Prepreg qualification, fabrication consistency, in-situ quality control, 4) Pre-launch readiness, range testing on commercial tooling demonstration articles, and the delivery of a fully characterized, cost reduced, 52-inch by 100-foot prepregged evaluation sample. BENEFIT: The proposed material can serve as a highly conductive light weight coating that has very low impedance in the 1 to 20 GHz region. It is also CTE matched to graphite, and is likely to be immune to corrosion in marine and other harsh environments. It has been shown that it can be handled in normal industrial manufacturing processes such as prepreg operations without major adjustments to normal manufacturing procedures. In addition, this material is free of nickel, is non-toxic and has broad military and civil applications. For example, EMI shielding of data or control cables with dramatically reduced weight and the ability to bond to graphite epoxy and therefore provide highly conductive layers. All of the envisioned applications for this material can be fabricated from 52-inch wide rolls of stock material. The areal density of the material required to achieve these properties is between 15 and 20 gsm and when prepregged, approximately 60-80 gsm.