Morphology and electrical properties of polymethylmethacrylate/poly(styrene‐co‐acrylonitrile)/multi‐walled carbon nanotube nanocomposites

Abstract

Nanocomposites of blends of polymethylmethacrylate (PMMA) and poly(styrene-co-acrylonitrile) (SAN) with multi-walled carbon nanotubes (MWCNTs) were prepared by melt mixing in a twin-screw extruder. The dispersion state of MWCNTs in the matrix polymers was investigated using transmission electron microscopy. Interestingly enough, in most of the nanocomposites, the MWCNTs were observed to be mainly located at SAN domains, regardless of the SAN compositions in the PMMA/SAN blend and of the processing method. One possible reason for this morphology may be the p-p interactions between MWCNTs and the phenyl ring of SAN. The shift in G-band peak observed in the Raman spectroscopy may be the indirect evidence proving these interactions. The percolation threshold for electrical conductivity of PMMA/SAN/ MWCNT nanocomposites was observed to be around 1.5 wt %. Nanocomposites with PMMA-rich composition showed higher electrical conductivity than SAN-rich nanocomposites at a fixed MWCNT loading. The dielectric constant measurement also showed composition-dependent behavior.

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.…”

“…PMMA/CNT nanocomposites can be used in various fields, such as, electromagnetic interference (EMI) shielding materials, transparent conducting films, gas sensors, etc. Considerable research has already been carried out on the electrical properties of PMMA/CNT nanocomposites prepared through different methods . For instance, McClory et al studied the electrical properties of PMMA/multiwall carbon nanotube (MWCNT) nanocomposites prepared by melt mixing and found a DC conductivity of 10 −7 S cm −1 at 1 wt % MWCNT loading.…”

“…Kim et al reported a DC conductivity ≈5 × 10 −4 S cm −1 in solution blended PMMA/MWCNT nanocomposites thin film at 3 wt % CNT loading. Lee et al obtained a DC conductivity of 1 × 10 −5 S cm −1 at 1.5 wt % MWCNT loading in melt‐extruded PMMA/SAN/MWCNT nanocomposites. Logakis et al reported a DC conductivity ≈5 × 10 −4 S cm −1 at 1 wt % MWCNT loading in melt‐blended PMMA/MWCNT nanocomposites.…”

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

“…Figure 7b represents the frequency dependence AC conductivity of the nanocomposites with a variation of CNT loading at a constant concentration of HIPS (60 wt%) bead. Compared to the pure HIPS, a higher Shrivastava et al -eXPRESS Polymer Letters Vol.8, No.1 (2014) [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] conductivity is observed in the nanocomposites with increasing wt% of CNT loading. With an increase in CNT loading from 0~0.6 wt%, a sharp increase in conductivity was found in the low frequency region.…”

“…For instance, McClory et al [23] studied the electrical conductivity of melt mixed HIPS/MWCNT nanocomposites and found an electrical conductivity of ~10 -6 S/cm at 4 wt% loading of MWCNT in HIPS. Lee et al [24] and Göldel et al [25] studied the electrical properties of melt extruded SAN/MWCNT nanocomposites and found !4·10 -4 and !1·10 -4 S/cm at 2 and 1.5 wt% MWCNT loadings, respectively. A DC conductivity of !10 -2 S/cm at 15 wt% of CNT loading in poly (styrene-co-butyl acrylate)/MWCNT nanocomposites was reported by Dufresne et al [26].…”