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Understanding the cross-linking reactions in highly oxidized graphene/epoxy nanocomposite systems

Understanding the cross-linking reactions in highly oxidized graphene/epoxy nanocomposite systems
Understanding the cross-linking reactions in highly oxidized graphene/epoxy nanocomposite systems
Graphene oxide (GO) was produced using acidic graphite oxidation and dispersed within an epoxy matrix using a solvent-based technique, to give nanocomposites containing up to 2 wt% of GO. Transmission and scanning electron microscopy revealed a fine dispersion of graphitic sheets which alters the nanocomposite’s fractured surface morphology, while Fourier transform infrared spectroscopy revealed an excess of epoxide groups in the system, which are associated with the included GO. These additional moieties react with hardener amine groups and, consequently, displace the reaction stoichiometry away from the optimum. The result of this is a change in the network architecture and, in particular, the introduction of epoxy-terminated branches, which modify the dielectric γ relaxation. During post-curing, hydroxyl groups on the GO surface react with residual epoxide groups through etherification reactions, to give a marked increase in the glass transition temperature. These reactions lead to increased interfacial interactions between the GO and the matrix, which contribute to an increase in tensile performance. In addition, post-curing also reduces the defect content within the GO lattice which, in turn, increases the electrical conductivity, dielectric permittivity and low frequency losses of the system. Associated chemical pathways are proposed.
0022-2461
3035-3051
Vryonis, Orestis
4affde05-88f2-436f-b036-dceedf31ea9c
Virtanen, Suvi
5f98459d-e6b8-45d4-bdf8-85d264b3f43a
Andritsch, Thomas
8681e640-e584-424e-a1f1-0d8b713de01c
Vaughan, Alun
6d813b66-17f9-4864-9763-25a6d659d8a3
Lewin, Paul
78b4fc49-1cb3-4db9-ba90-3ae70c0f639e
Vryonis, Orestis
4affde05-88f2-436f-b036-dceedf31ea9c
Virtanen, Suvi
5f98459d-e6b8-45d4-bdf8-85d264b3f43a
Andritsch, Thomas
8681e640-e584-424e-a1f1-0d8b713de01c
Vaughan, Alun
6d813b66-17f9-4864-9763-25a6d659d8a3
Lewin, Paul
78b4fc49-1cb3-4db9-ba90-3ae70c0f639e

Vryonis, Orestis, Virtanen, Suvi, Andritsch, Thomas, Vaughan, Alun and Lewin, Paul (2019) Understanding the cross-linking reactions in highly oxidized graphene/epoxy nanocomposite systems. Journal of Materials Science, 54 (4), 3035-3051. (doi:10.1007/s10853-018-3076-8).

Record type: Article

Abstract

Graphene oxide (GO) was produced using acidic graphite oxidation and dispersed within an epoxy matrix using a solvent-based technique, to give nanocomposites containing up to 2 wt% of GO. Transmission and scanning electron microscopy revealed a fine dispersion of graphitic sheets which alters the nanocomposite’s fractured surface morphology, while Fourier transform infrared spectroscopy revealed an excess of epoxide groups in the system, which are associated with the included GO. These additional moieties react with hardener amine groups and, consequently, displace the reaction stoichiometry away from the optimum. The result of this is a change in the network architecture and, in particular, the introduction of epoxy-terminated branches, which modify the dielectric γ relaxation. During post-curing, hydroxyl groups on the GO surface react with residual epoxide groups through etherification reactions, to give a marked increase in the glass transition temperature. These reactions lead to increased interfacial interactions between the GO and the matrix, which contribute to an increase in tensile performance. In addition, post-curing also reduces the defect content within the GO lattice which, in turn, increases the electrical conductivity, dielectric permittivity and low frequency losses of the system. Associated chemical pathways are proposed.

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Submitted date: 23 August 2018
Accepted/In Press date: 25 October 2018
e-pub ahead of print date: 31 October 2018
Published date: February 2019

Identifiers

Local EPrints ID: 425735
URI: http://eprints.soton.ac.uk/id/eprint/425735
ISSN: 0022-2461
PURE UUID: f0bed46e-1eda-44b6-b8e9-070ff1aad7ca
ORCID for Suvi Virtanen: ORCID iD orcid.org/0000-0003-0502-3183
ORCID for Thomas Andritsch: ORCID iD orcid.org/0000-0002-3462-022X
ORCID for Alun Vaughan: ORCID iD orcid.org/0000-0002-0535-513X

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Date deposited: 02 Nov 2018 17:30
Last modified: 30 Jan 2020 01:39

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