Glass transition improvement in epoxy/graphene composites

Ribeiro, Hélio; Silva, Wellington Marcos da; Rodrigues, Marco‐Tulio F.; Neves, Juliana Cardoso; Paniago, R.; Fantini, C.; Calado, Hállen Daniel Rezende; Seara, Luciana Moreira; Silva, Glaura G.

doi:10.1007/s10853-013-7478-3

Cited by 54 publications

(21 citation statements)

References 51 publications

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“…The T g ∞ of the 0.5 wt % GO‐modified system is significantly higher than that of the neat epoxy, being observed an increment of 16.5 °C. Similar increases in the T g ∞ were observed for the nanocomposites produced with an epoxy and different types of modified graphene . This increase can be ascribed to the filler effect which broaden the segmental motion range.…”

Section: Resultssupporting

confidence: 72%

Effects of graphene oxide and chemically reduced graphene oxide on the curing kinetics of epoxy amine composites

Monteserín

Blanco

Aranzabe

et al. 2017

J of Applied Polymer Sci

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The curing kinetics of epoxy nanocomposites prepared by incorporating graphene oxide (GO) and chemically reduced graphene oxide (rGO) have been studied using isothermal and nonisothermal differential scanning calorimetry. The kinetic parameters of the curing processes in these systems have been determined by a Kamal and Sourour phenomenological model expanded by a diffusion factor. The predicted curves determined using the kinetic parameters fit well with the isothermal DSC thermograms revealing the proposed kinetic equation clearly explains the curing kinetics of the prepared epoxy amine nanocomposites. Experimental and modeling results demonstrate the presence of an accelerating effect of the GO on the cure of the resin matrix. The use of rGO instead of GO resulted in a slight acceleration reaction rate due to the reduced presence of oxidation groups in rGO.

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Section: Resultssupporting

confidence: 72%

Effects of graphene oxide and chemically reduced graphene oxide on the curing kinetics of epoxy amine composites

Monteserín

Blanco

Aranzabe

et al. 2017

J of Applied Polymer Sci

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“…In this study, improvements in the mechanical and thermal properties of PU/CNT composites have been observed: T g increased by 20 C, and the elastic modulus increased by 47% after adding a small amount of MWCNT-ox to the nanocomposites (0.5 wt %). Furthermore, the oxidized nanotubes are better dispersed in the matrix, as characterized by optical and electron microscopies.…”

Section: Discussionmentioning

confidence: 62%

Thermosetting polyurethane‐multiwalled carbon nanotube composites: Thermomechanical properties and nanoindentation

Lopes

Castro

Seara

et al. 2014

J of Applied Polymer Sci

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In this study, composites based on a thermoset polyurethane elastomer (PU) and multiwalled carbon nanotubes (MWCNT) in the case of a PU of high elastic modulus (>200 MPa) are analyzed for the first time. As-grown and modified nanotubes with 4 wt % of oxygenated functions (MWCNT-ox) were employed to compare their effect on composite properties and maxima mechanical properties (elastic modulus and tensile strength) were reached at 0.5 wt % of MWCNT-ox. Furthermore, by examining the morphology using optical and electron microscopies better dispersion and interaction of the nanotube-matrix was observed for this material. DMTA data supports the observation of an increase in the glass transition temperature of 20 C in the nanocomposites compared with the thermoset PU, which is an important result because it shows extended reliability in extreme environments. Finally, nanoindentation tests allowed a comparison with the conventional mechanical tests by measuring the elastic modulus and hardness at the subsurface of PU and the nanocomposites.

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“…Nanoparticle dispersion usually imposes a challenge for obtaining actual nanodielectric systems, where the nanoparticles, due to their large specific surface area and surface tension forces, tend to agglomerate, producing a sub-microcomposites [11,12]. Many researchers have tried to overcome this by treating the nanofiller with matrix-compatible functionalities [13][14][15][16][17]. However, this treatment brings other parameters into play, such as changing the particle surface chemistry and water absorption, and thus, complicates the analysis of the influence of particle dispersion.…”

Section: Introductionmentioning

confidence: 99%

Influence of filler/matrix interactions on resin/hardener stoichiometry, molecular dynamics, and particle dispersion of silicon nitride/epoxy nanocomposites

et al. 2017

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The addition of nanofillers can have a significant influence on the resin stoichiometry of thermosetting polymer systems. Based on differential scanning calorimetry (DSC) results, it is estimated that the inclusion of 2 and 5 wt% of silicon nitride nanofiller displaces the resin/hardener stoichiometry of an epoxy/amine network by 6.5 and 18%, respectively. Dielectric spectroscopy results confirm the above findings, in that the spectra of the nanocomposite samples were found to be equivalent to the spectra of unfilled samples when the above stoichiometric effect was taken into account. Therefore, this study provides clear evidence that the presence of a nanofiller can directly and significantly affect the curing process of an epoxy network. Consequently, this should always be considered when introducing nanofillers into thermosetting matrices. These results indicate the presence of covalent bonding between the nanoparticles and the surrounding polymer and, therefore, provide an opportunity to explore the influence of this bonding on the molecular dynamics of the polymer layer around the particles. However, the obtained DSC and dielectric spectroscopy results suggest that, in the system considered here, either the covalent bonding does not have an appreciable influence on the segmental dynamics of the polymer, as revealed by these techniques, or that the thickness of the affected layer is less than 1 nm and therefore too small to be distinguished from experimental uncertainties.

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Glass transition improvement in epoxy/graphene composites

Cited by 54 publications

References 51 publications

Effects of graphene oxide and chemically reduced graphene oxide on the curing kinetics of epoxy amine composites

Effects of graphene oxide and chemically reduced graphene oxide on the curing kinetics of epoxy amine composites

Thermosetting polyurethane‐multiwalled carbon nanotube composites: Thermomechanical properties and nanoindentation

Influence of filler/matrix interactions on resin/hardener stoichiometry, molecular dynamics, and particle dispersion of silicon nitride/epoxy nanocomposites

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