Lightweight highly conductive composites for EMI shielding

Triton Systems, Inc., in cooperation with NASA/Glenn Research Center, has s uccessfully addressed the problem of shielding electronic devices in space from EMI (electromagnetic interference) - with lower weight composite shiel ds compared to presently used aluminum or tantalum shields. Triton has deve loped a new unique low-density composite EMI shield using NASA-developed br omine-intercalatedgGraphite paired to Triton's electrically conductive epox y matrix. Both 1- and 2-ply composites have been prepared (only 0.36 and .7 2 mm thick) that have been shown to have EMI shielding equal to that of an aluminum control [for Q-band microwave radiation]. Because present aluminum EMI shields must be about 2 mm in thickness for strength arf a the new Tri ton/NASA shield can be as thin as 0.36 mm for equal strength and shielding, we have developed a potential weight savings of 88% compared to aluminum. Composites of bromine-intercalated graphite in epoxy were developed by NASA for EMI and have been improved upon by addition of Triton's unique conduct ive epoxy resin for the composite matrix. Triton's 100% polymeric conductiv e epoxy increases shielding effectiveness through enhanced surface and inte rnal conductivity of the entire composite. Typical 2-ply composites have pr ovided Q-band EMI shielding greater than 85dB. Furthermore, lightweight com posites with high strength and stiffness can be made by conventional compos ite processing techniques. Data are presented on the EMI shielding performa nce of the Triton/NASA composite system.