Study of epoxy/CNT nanocomposites prepared via dispersion in the hardener

Abstract

In this study, carboxylated (SWCNT-c) and pristine (SWCNT) single-walled carbon nanotubes were randomly dispersed in a hardener prior to mixing it with an epoxy resin. The influence of several parameters on the dispersion process were investigated. The produced samples were characterized by infrared spectroscopy, differential scanning calorimetry, dilatometry, dynamic mechanical analysis, scanning electron microscopy and mechanical testing (tensile, flexural and microhardness). The results obtained with the nanocomposites with SWCNT-c suggested that the lowest time and amplitude of sonication improved the mechanical properties. The use of a solvent (acetone) was important to improve dispersion, ultimately increasing microhardness and Young's Modulus up to 32%. Nanocomposites with 0.25 wt. (%) SWCNT-c presented superior mechanical properties compared to those with 0.50 wt. (%) SWCNT. Two simple mathematical models (rule of mixtures and Halpin-Tsai) were used to predict Young's Modulus of the composites yielding results very close to the experimental ones.

Microencapsulated amino‐functional polydimethylsiloxane as autonomous external self‐healing agent for epoxy systems

“…Figure shows a DSC curve of a cured DGEBA/PDMS‐a/TETA specimen, prepared by the mixture of PDMS‐a/TETA 50/50 (m/m) with an equimolar amount of DGEBA, indicating a glass transition temperature (Tg) of 49.8°C. This Tg is well below the reported value for the same DGEBA/TETA system used in this work, around 107°C, pointing out the role of PDMS‐a in the toughening of DGEBA/mPDMS‐a/mTETA systems after self healing.…”

Reinforcement and toughening mechanisms in polymer nanocomposites – Carbon nanotubes and aluminum oxide

“…5 (b), one can note the pull-out occurring in one of the high concentration regions. In another study of the same research group in a similar system (epoxy/CNTs), there is strong evidence of pullout found by SEM [36]. It can also be seen in Fig.…”

Investigation of cure kinetics in epoxy/multiwalled carbon nanotube nanocomposites

“…These properties show a trend toward higher modulus and strength and a trend toward lower strain for higher MWCNT contents. Although it can be debated that the variations are in the expected range, these effects are influenced by two other factors that reduce the aspect ratio of the nanotubes or influence the presence of the CNT on the curing degree of the thermoset resin. This correlation has been previously reported .…”