Comparative study of structure, mechanical and electromagnetic interference shielding properties of carbon nanotube buckypapers prepared by different dispersion media

Abstract

In order to prepare multi-wall carbon nanotube (MWCNT) buckypapers (BPs) with excellent comprehensive properties, an investigation was conducted regarding the effect of dispersing medium on CNT dispersions and resultant BPs. Three types of MWCNTs with different lengths and diameters, denoted as CNT-A, CNT-B and CNTC, were dispersed into water, ethanol and 1-methyl-2-pyrrolidone, respectively. The dispersion stability was monitored by UV–vis spectroscopy and conductivity meter. The results showed that all MWCNT/water dispersions were far superior to MWCNT/ethanol dispersion in stability, but slightly inferior in monodispersity. Subsequently, BPs prepared by vacuum filtration using the above-mentioned dispersions were investigated to clarify the pore structure, electrical, mechanical and electromagnetic shielding properties. Compared with BPs prepared with CNT-A/ethanol dispersion (BP-A-E), the BP prepared with CNT-A/water dispersion (BP-A-W) showed smaller pore size, and exhibited significantly improvement in electrical conductivity (74%), strength (665%). A super high absorption-dominated electromagnetic interference shielding effectiveness (SE) of 101.7 dB was achieved by BP-A-W of 450 μm thick in the range of 8.2–18 GHz, which was 26% higher than that of BP-A-E. A notable SE of 48.4 dB and a high specific SE of 29,300 dB·cm2/g were obtained by BP of 45 μm thick prepared with CNT-C/water dispersion.