Effects of Graphene Oxide and Chemically-Reduced Graphene Oxide on the Dynamic Mechanical Properties of Epoxy Amine Composites.

Cristina Monteserín,Jose Luis Vilas,Ana Aranzabe,Estibaliz Aranzabe,Aitor Larrañaga-Varga,Miren Blanco,Jose Manuel Laza

doi:10.3390/polym9090449

Cristina Monteserín, Jose Luis Vilas + Show 5 more

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https://doi.org/10.3390/polym9090449

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Abstract

Composites based on epoxy/graphene oxide (GO) and epoxy/reduced graphene oxide (rGO) were investigated for thermal-mechanical performance focusing on the effects of the chemical groups present on nanoadditive-enhanced surfaces. GO and rGO obtained in the present study have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD) demonstrating that materials with different oxidation degrees have been obtained. Thereafter, GO/epoxy and rGO/epoxy nanocomposites were successfully prepared and thoroughly characterized by dynamic mechanical thermal analysis (DMTA) and transmission electron microscopy (TEM). A significant increase in the glass transition temperature was found in comparison with the neat epoxy. The presence of functional groups on the graphene surface leads to chemical interactions between these functional groups on GO and rGO surfaces with the epoxy, contributing to the possible formation of covalent bonds between GO and rGO with the matrix. The presence of oxidation groups on GO also contributes to an improved exfoliation, intercalation, and distribution of the GO sheets in the composites with respect to the rGO based composites.

Highlights

Epoxy systems are one of the most important organic matrices in the composite industry, frequently used in demanding applications, such as matrices in reinforced composites, adhesives in the aerospace industry, surface coatings, etc., due to their excellent mechanical properties, high chemical and thermal stability, excellent adhesive properties, good corrosion resistance, and low shrinkage during the curing process
graphene oxide (GO) was prepared from natural graphite with the modified Hummer oxidation method and, thereafter, hydrazine was employed to prepare reduced graphene oxide (rGO)
The GO and rGO have been thoroughly characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD)

Summary

Introduction

Epoxy systems are one of the most important organic matrices in the composite industry, frequently used in demanding applications, such as matrices in reinforced composites, adhesives in the aerospace industry, surface coatings, etc., due to their excellent mechanical properties, high chemical and thermal stability, excellent adhesive properties, good corrosion resistance, and low shrinkage during the curing process. Their brittleness, poor resistance to crack propagation and poor wear resistance limit their applications. Inorganic particles, such as silica and alumina, with diameters between 4 and 100 μm, have been used to increase the toughness of epoxies without sacrificing their basic properties, but the presence of numerous and relatively large inorganic particles increases the viscosity leading to poor dispersion and processing difficulties [6,7]

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