Electrical percolation, morphological and dispersion properties of MWCNT/PMMA nanocomposites

Abstract

Nanocomposites of poly (methyl methacrylate) (PMMA) and carbon nanotubes have a high potential for applications where conductivity and low specific weight are required. This piece of work concerns investigations of the level of dispersion and morphology on the electrical properties of in situ polymerized nanocomposites in different concentrations of multi-walled carbon nanotubes (MWCNT) in a PMMA matrix. The electrical conductivity was measured by the four point probe. The morphology and dispersion was analyzed by Transmission Electron Microscopy (TEM) and Small Angle X-ray Scattering (SAXS). The correlation between electrical conductivity and the MWCNT amount, presented a typical percolation behavior, whose electrical percolation threshold determined by power law relationship was 0.2 vol. (%) The exponent t from the percolation power law indicated the formation of a 3D network of randomly arranged MWCNT. SAXS detected that the structures are intermediate to disks or spheres indicating fractal geometry for the MWCNT aggregates instead of isolated rods. HR-TEM images allowed us to observe the MWCNT individually dispersed into the matrix, revealing their distribution without preferential space orientation and absence of significant damage to the walls. The combined results of SAXS and HR-TEM suggest that MWCNT into the polymeric matrix might present interconnected aggregates and some dispersed single structures.

Assessment of Percolation Threshold Simulation for Individual and Hybrid Nanocomposites of Carbon Nanotubes and Carbon Black

“…In order to calculate the fillers volume fraction (V) the density of the fillers were determined by gaseous pycnometry, and for PMMA, by liquid pycnometry. Singleconductive-filler filled systems (SCFFS) formulations were previously studied to obtain the p c published as p c = 0.2 vol.% for CNT 17 and p c = 1.5 vol. % for CB 18 .…”

“…Figure 2 shows the MCFFS and SCFFS electrical conductivity. The results for the single systems are published elsewhere 17,18 and were shown here to compare the different systems. Samples 1-4 presented electrical conductivity while for samples 5-8 no conductivity was observed, evidencing that Sun's model fits the studied systems.…”

“…This result is consistent with p c experimental value of CNT/PMMA of 0.2 % vol. 17 , which when converted to mass value is 0.45%. This suggests the suitability of the current 3D simulator may be more representative when determining the percolation threshold.…”

Flexible and Stretchable Temperature Sensors Fabricated Using Solution‐Processable Conductive Polymer Composites

“…The critical exponent t was derived from linear fitting of the log c versus (∅ − ∅ c )/(1 − ∅ c ) data (shown inset in Figure 5a), and was found to be 2.41 ± 0.23. For 3D networks, t has been predicted to be between 1.65 and 2, [55] while for 2D networks t is expected to be 1.33. [56] A larger t suggests larger size of the clusters inside the polymer matrix.…”

Peculiarities of near-electrode relaxation processes in the polyethylene melt filled with graphite and carbon black

“…Therefore, to expand their functionality, studies are performed using different types of polymers and fillers [1][2][3][4][5][6][7][8]. In recent years for such studies, the use of nanoparticles is typical [9][10].…”