Modifications of mechanical, thermal, and electrical characteristics of epoxy through dispersion of multi-walled carbon nanotubes in supercritical carbon dioxide

Abstract

A supercritical carbon dioxide (SCC) process of dispersion of multi-walled carbon nanotubes (MWCNTs) into epoxy resin has been developed to achieve MWCNT/epoxy composites (CECs) with improved mechanical, thermal, and electrical properties. The synthesis of CECs has been executed at a MWCNT (phr) concentration ranging from 0.1 to 0.3 into epoxy resin (0.1 mol) at 1800 psi, 90°C, and 1500 rpm over 1 h followed by curing of the MWCNT/epoxy formulations with triethylene tetramine (15 phr). The effect of SCC treatment on the qualitative dispersion of MWCNTs at various concentrations into the epoxy has been investigated through spectra analyses and microscopy. The developed SCC assisted process provides a good dispersion of MWCNTs into the epoxy up to a MWCNT concentration of 0.2. The effects of SCC assisted dispersion at various concentrations of MWCNTs on modification of mechanical, thermal, dynamic mechanical thermal, and tribological properties and the electrical conductivity of CECs have been investigated.

Enhanced corrosion protection performance with MWCNT dispersed epoxy coating prepared under supercritical CO2 assistance

“…Figure A displays the AFM image of MWCNT/epoxy coating. The large smooth zones with a bright appearance may be attributed to the greater force experienced by the cantilever tip during contact with MWCNTs, whereas dark areas of the image corresponded to amorphous phases of the epoxy matrix . The MWCNT/epoxy coating showed average roughness of 21.10 nm with no significant agglomeration.…”

“…The dissolving properties and fast diffusion rate of scCO 2 enable the quick incorporation of MWCNT and its homogeneous dispersion throughout the polymer. Upon depressurization, the CO 2 quickly diffuses out and gets completely removed on vacuum degassing . Prior to curing, the dispersion of 1 wt% MWCNT into epoxy resin was optimized through UV‐visible spectroscopy on the basis of Van Hove singularities .…”

“…Upon depressurization, the CO 2 quickly diffuses out and gets completely removed on vacuum degassing . Prior to curing, the dispersion of 1 wt% MWCNT into epoxy resin was optimized through UV‐visible spectroscopy on the basis of Van Hove singularities . Figure illustrates the UV‐visible spectra for the dispersion of 1 wt% MWCNT into epoxy resin at varied scCO 2 pressure.…”

“…In a report by Chang et al, it was confirmed that the residual acetone was indeed retained in the prepared MWCNT‐graphene epoxy nanocomposite even after post‐heating treatment . Moreover, under the physical dispersion methods like grinding, ball milling, and ultrasonication or a combination of them, MWCNTs are seriously damaged limiting their performance . Consequently, Kumar et al attempted an innovative dispersion by simultaneously applying ultrasonic waves and shear force generated by axial flow impeller to obtain homogeneous MWCNT in epoxy matrix .…”

Finite element modeling of carbon nanotube agglomerates in polymers

“…It has been well recognized from experiments and microscope observations that CNT agglomerates act as defects causing, in the worst scenario, a reduction in the mechanical properties of neat polymer [2][3][4], and in the best scenario, a smaller than the desired increase in the properties [5][6][7][8][9][10][11][12]. Besides recognition of the negative effect of CNT agglomerates, little has been done on the understanding of the role of agglomerates' geometrical characteristics.…”