The influence of mechanical dispersion of MWCNT in epoxy matrix by calendering method: Batch method versus time controlled

Effect of the addition of multi-walled carbon nanotubes on the thermomechanical properties of epoxy resin

“…However, the full potential of employing CNTs as reinforcement in polymers has been severely limited by the difficulties with dispersion of entangled CNTs during processing . Various efforts to disperse CNTs in viscous resin have been made, such as physical mixing, including ultrasonication , calendaring , ball milling and extrusion , or a combination of these. Chemical modification via functionalization of CNTs has also been investigated for forming covalent bonds with functional groups in polymeric resins.…”

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

“…SEM reveals the presence of stress concentration in the matrix of fractured epoxy due to agglomeration of MWCNTs. With increasing concentration of MWCNTs, modification of the roughness of the fractured surface was observed mainly in the areas of the CECs where the crack propagation initiated, which is common in brittle epoxy resin fractures [31,35,36]. The spectral, microstructure, and electrical conductivity data reveal the capability of SCC to provide well dispersed MWCNT/epoxy formulations up to a filler concentration of 0.2 at applied supercritical processing conditions within 1h without sonication [18,29,31].…”

“…Mechanical dispersion, on the other hand, involves the use of expensive, toxic, and flammable organic solvents and lengthens the manufacturing process. The calendering approach has proved to be an effective method for achieving appropriate nanoreinforcement dispersion in epoxy resins without causing major damage to the nanoreinforcement compared to sonication and high shear mixing techniques, which present limited dispersion effectiveness and may cause damage to the nanoreinforcement when the processing time is lengthened to increase dispersion [31]. With respect to evaluating the dispersion of different types of nanoparticles, depending on the demanded scale, different microscopy methods such as transmission electron microscopy, scanning electron microscopy, and atomic force microscopy are amongst the most widely used techniques.…”

“…In recent decades, efforts have been directed towards the development of physical-mechanical or chemical processes to enhance the dispersion of CNTs in an epoxy matrix [25][26][27][28][29]. Physical methods involve breaking up agglomerates through calendaring, grinding, ball milling, high speed shearing, high-pressure homogenization, ultrasonication, a combination thereof [30,31], or chronoamperometry [32]. With regard to chemical methods, the purification procedure involves the removal of metallic catalyst residues, which arise from the synthesis of CNTs and the creation of functional groups on their surface to improve the interfacial interactions between the polymers and CNTs [16,31,32].…”

“…Physical methods involve breaking up agglomerates through calendaring, grinding, ball milling, high speed shearing, high-pressure homogenization, ultrasonication, a combination thereof [30,31], or chronoamperometry [32]. With regard to chemical methods, the purification procedure involves the removal of metallic catalyst residues, which arise from the synthesis of CNTs and the creation of functional groups on their surface to improve the interfacial interactions between the polymers and CNTs [16,31,32]. CNTs are seriously damaged, especially when a probe sonicator is employed, suggesting the generation of defects on the CNT surface.…”