Fabrication of Carbon Nanotubes-Based Efficient Electromagnetic Waves Shields Nanocomposites Using Electro-Mechanically Dispersion Technique

This research is trying to fabricate an efficient and economical EMIS X-band using Electro-Mechanically Dispersion Technique (EMDT). For this purpose, first, poly-methyl-methacrylate (PMMA)-based nanocomposites produced with the different weight percentages between 0 to 2 %, by two EMDT and ultrasonic probe methods. The structure of samples were evaluated by scanning electron microscope and Raman spectroscopy. The electrical resistivity of samples were also measured to determine percolation threshold. At the final assessments, electromagnetic behavior of the samples were examined. The results shows percolation threshold was occurred at the concentration of 0.2 wt.% in EMDT, while this event was observed at the concentration of 1 wt.% for ultrasonic method. According to the microscopic study and the results of Raman spectroscopy, the ability of EMDT in protecting the structure and length of CNTs was detected as the main factor to decrease 80 % in percolation threshold concentration. The investigation of electromagnetic properties of samples at percolation threshold show that EMDT method, despite having a concentration equal to 20% of the ultrasonic probe method, offers effective EMIS of 38 dB, which is 16% higher than the ultrasonic probe method. However, the advantage of EMDT compared to earlier presented methods relates to reduce 25 times the concentration and simultaneously increasing the absorption from 25 to 36 dB.