Shielding Effectiveness of Electromagnetic Interference of MWCNT/PMMA Composites

摘要

MWCNT/PMMA composites have been prepared by in-situ and ex-situ method. SEM microphotographs shaved that the MWCNT/PMMA composites prepared by in-situ method possess better adhesion than that by ex-situ method. The surface electrical resistivity of the MWCNT/PMMA composites decreased from 9.75x10~(15)Ω (neat PMMA) to 8.62 X 10~2Ω [(4.76 wt% MWCNT/PMMA prepared by ex-site method, decreased 13 orders) and 5.92 x 10~2Ω (4.76 wt% MWCNT/PMMA prepared by in-situ method, decreased 13 orders). The percolation threshold was 0.74wt% and 0.25wt% for the MWCNT/PMMA composites prepared by ex-situ and in-situ method, respectively. Effects of processing method of the MWCNT/PMMA, MWCNT content and composites stacking process on the shielding effectiveness (SE) of electromagnetic interference (EMI) of MWCNT/PMMA composites were investigated. SE of EMI of MWCNT/PMMA increased with increased MWCNT content. In-situ method prepared composites exhibited higher SE value. Furthermore, composites prepared by stacking ten layers of 0.1mm MWCNT/PMMA possessed higher SE than that of one piece of 1.0mm bulk MWCNT/PMMA composites. The characteristic of SE spectra of all systems were also discussed.