A facile route to develop electrical conductivity with minimum possible multi‐wall carbon nanotube (MWCNT) loading in poly(methyl methacrylate)/MWCNT nanocomposites

Abstract

Today, we stand at the threshold of exploring carbon nanotube (CNT) based conducting polymer nanocomposites as a new paradigm for the next generation multifunctional materials. However, irrespective of the reported methods of composite preparation, the use of CNTs in most polymer matrices to date has been limited by challenges in processing and insufficient dispersability of CNTs without chemical functionalization. Thus, development of an industrially feasible process for preparation of polymer/CNT conducting nanocomposites at very low CNT loading is essential prior to the commercialization of polymer/CNT nanocomposites. Here, we demonstrate a process technology that involves in situ bulk polymerization of methyl methacrylate monomer in the presence of multi‐wall carbon nanotubes (MWCNTs) and commercial poly(methyl methacrylate) (PMMA) beads, for the preparation of PMMA/MWCNT conducting nanocomposites with significantly lower (0.12 wt% MWCNT) percolation threshold than ever reported with unmodified commercial CNTs of similar qualities. Thus, a conductivity of 4.71 × 10−5 and 2.04 × 10−3 S cm−1 was achieved in the PMMA/MWCNT nanocomposites through a homogeneous dispersion of 0.2 and 0.4 wt% CNT, respectively, selectively in the in situ polymerized PMMA region by using 70 wt% PMMA beads during the polymerization. At a constant CNT loading, the conductivity of the composites was increased with increasing weight percentage of PMMA beads, indicating the formation of a more continuous network structure of the CNTs in the PMMA matrix. Scanning and transmission electron microscopy studies revealed the dispersion of MWCNTs selectively in the in situ polymerized PMMA phase of the nanocomposites. Copyright © 2012 Society of Chemical Industry

Sequential mixing as effective method in the reduction of percolation threshold of multiwall carbon nanotube in poly(methyl methacrylate)/high‐density poly(ethylene)/MWCNT nanocomposites

“…Immense research interest has been focused on polymer/carbon nanotube (CNT) nanocomposites in the last few decades because of their dramatically improvement in properties relative to neat polymer and to yield multifunctional materials . The high aspect ratio of CNTs allows property enhancement at lower concentrations as compared with conventional filler particles such as carbon black or nanoclays.…”

“…Various thermoplastics, such as poly(methyl methacrylate) (PMMA), polycarbonate (PC), etc. have been used to prepare polymer/CNT nanocomposites with improved electrical properties.…”

“…The incorporation of only 0.01 wt % of MWCNT in SAN matrix in presence of the compatibilizer led to a dramatic increase in both Young's modulus and tensile strength of SAN matrix without sacrificing the inherent elongation at break of SAN. Shrivastava et al reported an electrical percolation threshold of 0.12 wt % in the PMMA/MWCNT nanocomposites following a method involving the selective dispersion of MWCNT in the in situ bulk polymerized PMMA in the presence of PMMA beads. In another work, Shrivastava et al achieved a percolation threshold of 0.032 wt % of MWCNT in SAN/ MWCNT nanocomposites via exclusion of some portions in the nanocomposites through addition of the SAN beads during in situ polymerization of styrene and acrylonitrile in the oligomeric stage.…”

Low percolation threshold and high electrical conductivity in melt-blended polycarbonate/multiwall carbon nanotube nanocomposites in the presence of poly(ε-caprolactone)

“…In the lower frequency region, dielectric loss was increased with increase in CNT loading, while a marginal effect was found at higher frequency. It has already been reported that, with increase in conducting filler loading, dielectric loss increases at lower frequency .…”

Influence of selective dispersion of MWCNT on electrical percolation of in-situ polymerized high-impact polystyrene/MWCNT nanocomposites

“…Thus, a very high conductivity in the polymer/CNT nanocomposites can be achieved at very low loadings of CNTs. The efficient dispersion of CNT into the polymer matrix is very difficult to achieve due to the high van der Waals forces between the individual CNT [13]. The small size and large surface area of the CNT lead to such high van der…”