Electrical conductivity behavior of epoxy matrix nanocomposites with simultaneous dispersion of carbon nanotubes and clays

Sene, Tarcísio Sanson; Ramos, Alexandre Moraes; Becker, Daniela; Coelho, Luci Boa Nova

doi:10.1002/pc.23332

Cited by 16 publications

(16 citation statements)

References 33 publications

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“…Experimental works with nanoclays in epoxy showed that for these systems the intercalated state is the probably the best option to improve K Ic . There are other experimental works that showed that a mixture of clays (two‐dimensional [2D] material) with CNTs (one‐dimensional [1D] material) can assist the formation of a percolated network of CNTs . In this work, we tried to combine a 2D and 1D of fullerenes (graphenes and CNTs) expecting a better dispersion through the material and also to obtain synergy between two nanofillers with promising results for toughening when employed isolated in the literature for brittle polymers.…”

Section: Introductionmentioning

confidence: 99%

Toughness and roughness in hybrid nanocomposites of an epoxy matrix

Coelho

2019

Polymer Engineering & Sci

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The present paper investigates the relationship between roughness and toughening mechanisms in hybrid epoxy nanocomposites with carbon nanotubes (CNT) and graphene nanoplatelets (GNPs). The role of adding a block copolymer (BC) to the studied systems was also investigated. The nanocomposites were prepared by means of high-energy sonication and in situ polymerization. All nanocomposites presented higher numerical values for K Ic than untoughened systems. The system containing 0.5 wt% of CNTs presented an increase of 35% in K Ic compared to neat epoxy, and the hybrid nanocomposite, at the proportion of 1:1 (CNT:GNP), with 0.5 wt% total of nanoparticles and also containing 0.5 wt % of BC, had an increase of 34% compared to the neat epoxy. Systems with higher amounts of graphene showed the highest roughness values, having crack deflection/exfoliation between the GNP layers as the main toughening mechanism. On the other hand, systems with more CNTs presented a lower fracture surface roughness, and the main toughening mechanism was bridging/break-up of the nanotubes. Hybrid systems have more types of mechanisms than simple ones. With only one type of nanoparticle, however, some of those mechanisms are not effective in increasing the toughness, only increasing the fracture surface roughness. POLYM. ENG.

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Section: Introductionmentioning

confidence: 99%

Toughness and roughness in hybrid nanocomposites of an epoxy matrix

Coelho

2019

Polymer Engineering & Sci

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“…Furthermore, it can immobilize, interrupt or even ramify the crack propagation , resulting in a higher absorption of fracture energy, which leads to an increase in fracture toughness . Despite that, experimental evidence indicates that, for nanoclays in epoxy matrices, the intercalated state is more efficient for the absorption of fracture energy than a homogeneous exfoliated state .…”

Section: Introductionmentioning

confidence: 99%

Role and sinergy of block copolymer and carbon nanoparticles on toughness in epoxy matrix

2017

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In this work, the relations between fracture surface roughness in mode I and the content of different carbon nanoparticles, graphene nanoplatelets (GNP) and carbon nanotubes (CNT) were systematically investigated. A block copolymer (BC) was also used to aid the dispersion process considering its role on fracture toughness. Both KIc and GIc were found to increase significantly with the addition of a BC along with carbon nanoparticles. Roughness measurements showed that the value of surface roughness (Ra) does not depend on the toughness, and decreases as the precrack distance increases. In the system with the greatest amount of graphene (0.5 wt%), the agglomerates impaired the material's tenacity and crack deflection with GNP delamination as the fracture mechanism. As for the CNT/epoxy nanocomposites with the BC, strong adhesion between matrix and nanotubes prevented debonding, so the CNTs break, rather than pulling out, after crack bridging, the so called sliding‐fracture mode failure. POLYM. COMPOS., 39:E2262–E2273, 2018. © 2017 Society of Plastics Engineers

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“…Sene et al. 24 also found an increase in electrical conductivity at low frequencies (percolation network) with pristine MWCNT 0.25 wt.% (∼0.15 vol.%) reaching values for electrical conductivity in the order of 10 −7 S/m. This electrical conduction happens by the displacement of the resonant π electrons of benzene rings through the concentric tubes.…”

Section: Resultsmentioning

confidence: 92%

Role of chemical funcionalization of carbon nanoparticles in epoxy matrices

Bello

Coelho

Becker

2017

Journal of Composite Materials

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The effects of the silanization of multi-walled carbon nanotubes and graphene nanoplatelets with 3-APTES on thermal, mechanical and electrical properties of epoxy nanocomposites were investigated. Nanocomposites containing pristine, oxidized and silanized nanoparticles of multi-walled carbon nanotubes or graphene nanoplatelets at two different concentrations (0.15 and 0.50 vol.%) were prepared by in situ polymerization without using solvents. The functionalized nanoparticles were characterized by Fourier-transform infrared, X-ray photoelectron spectroscopy, Raman spectroscopy and transmission electron microscope techniques. The oxidation and the silanization on the surface of both nanoparticles were confirmed by Fourier-transform infrared, X-ray photoelectron spectroscopy, Raman and transmission electron microscope analysis. The thermal properties of all studied materials were analyzed by differential scanning calorimetry and the mechanical properties by nanoindentation. The addition of both nanoparticles (pristine and functionalized) into the matrix did not show significant variations on thermal properties, but decreased values for glass transition temperature (Tg) compared to the neat resin. Higher values for modulus of elasticity and hardness of epoxy/nanocomposites were obtained when silanized multi-walled carbon nanotubes or oxidized graphene nanoplatelets were added into the matrix. Adding 0.15 vol.% of silanized multi-walled carbon nanotubes the modulus of elasticity increased in approximately 60%, whereas 0.50 vol.% this increase was greater than 90% compared to the neat resin. While adding 0.15 vol.% of oxidized graphene nanoplatelets, the modulus of elasticity increased approximately 83%, whereas 0.50 vol.% this increase was greater than 88% compared to the neat resin. The formation of percolating networks has been achieved only by pristine multi-walled carbon nanotubes addition at a concentration of 0.50 vol.% and by silanized graphene nanoplatelets at a concentration of 0.15 vol.%. However, for both carbon-based nanoparticles conductivities on the order of 10−7 S/m for frequencies near 100 Hz were observed.

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Electrical conductivity behavior of epoxy matrix nanocomposites with simultaneous dispersion of carbon nanotubes and clays

Cited by 16 publications

References 33 publications

Toughness and roughness in hybrid nanocomposites of an epoxy matrix

Toughness and roughness in hybrid nanocomposites of an epoxy matrix

Role and sinergy of block copolymer and carbon nanoparticles on toughness in epoxy matrix

Role of chemical funcionalization of carbon nanoparticles in epoxy matrices

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