Electromagnetic interference shielding materials using carbon nanotubes

탄소나노튜브를 이용한 전자파 차폐재

AC and DC conductivity of the MWNT(Multi walled nanotubes)/polyurethane composites were investigated with respect to the various oxidative conditions, where these means acid concentration, treatment temperature, and treatment time. We suppose that the conditions of oxidation of the MWNTS have a certain influence on the degree of functionalization, damages, and dispersion of the MWNT themselves. Futhermore, the electrical properties of the resulting composites strongly depend on the oxidative conditions of MWNTS. The conductivity of the composites produced by using the optimal condition was measured as a function of frequency with volume content of MWNTS. These experimental results were analyzed using percolation theory Electromagnetic interference shielding effectiveness (SE) of the mixtures of polyurethane (PU), optimized MWNTs, and silver (Ag) is measured in the frequency range from 10 MHz to 6 ㎓ by using ASTM D4935-89. The measured SEs of the mixtures could be controlled from about 55 dB to 85 dB with the compositions of Ag/MWNT and compounding methods(C1, C2).