Mechanical, Thermal and Electrical Properties of Epoxy Nanocomposites with Amine-Functionalized Reduced Graphene Oxide via Plasma Treatment

Abstract

A suitable functionalization of graphene and its derivatives can further enhance the material properties of nanocomposites. In contrast to chemical functionalization methods that have been extensively researched, functionalization by plasma treatment is relatively unexplored. In this work, we compare the mechanical, thermal and electrical characteristics of an epoxy matrix incorporating loadings from 0.00 to 1.50 wt% of non-functionalized (rGO) and amine-functionalized reduced graphene oxide (frGO) for which the functionalization is realized by plasma processing. No significant difference between the rGO- and frGO-including nanocomposites was observed with respect to the stiffness, strength, specific heat capacity, coefficient of thermal expansion and electrical conductivity. Yet, the composites with 1.50 wt% frGO (rGO) exhibited a thermal conductivity that was 27% (20%) higher than the neat polymer due to the enhanced interface, which enabled a better transfer of heat. In addition, a considerable increase in the specific heat capacity and thermal conductivity was established with rising temperatures. This information will facilitate the choice of materials depending on the loading and functionalization of graphene materials for composite applications with an epoxy matrix.

Mechanical, thermal, and electrical properties of amine‐ and non‐functionalized reduced graphene oxide/epoxy carbon fiber‐reinforced polymers

“…In comparison to the neat polymer, they observed a change of the Young's modulus (ultimate tensile strength) by +11% and +10% (À29% and À54%) for 1.50 wt.% untreated and nitrogendoped rGO, respectively. Similarly, in our previous work 44 using identical materials, dispersion, and mixing methods as in this work, we noticed a variation of the Young's modulus (ultimate tensile strength) by +12% and +14% (À34% and À31%) for the nanocomposites with 1.50 wt.% rGO and 1.50 wt.% frGO, respectively. This confirms a stronger effect of the fibrous reinforcement than that of doping the polymeric matrix with different types of graphene materials.…”

“…No significant difference was observed between the neat CFRP and frGO‐CFRP. Our previous work that used the same materials and processing methods confirmed a homogeneous dispersion of the used nanoparticles at 1.50 wt.% combined with favorable additive/matrix interactions, especially for frGO 43,44 . Hence, the lack of an enhanced shear strength of the frGO‐CFRP is likely to be caused by differences in the shape, size, and distribution of voids in the samples.…”

“…A characterization of the particles by Raman spectroscopy, Brunauer-Emmett-Teller theory, X-ray photoelectron spectroscopy, and scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy has been described in detail elsewhere. 43,44 The bisphenol-A-(epichlorohydrin) epoxy resin Biresin ® CR83 in conjunction with the amine-based hardener Biresin ® CH83-10 (mixture of isophorone diamine and polyoxypropylenediamine) were supplied by Sika Deutschland. This two-part resin system exhibits a low mixed viscosity (155 mPa s at 25 C) that favors wetting of the fibrous reinforcement.…”

“…Both powder materials were used as received. A characterization of the particles by Raman spectroscopy, Brunauer–Emmett–Teller theory, X‐ray photoelectron spectroscopy, and scanning electron microscopy coupled to energy‐dispersive X‐ray spectroscopy has been described in detail elsewhere 43,44 …”

Dynamic mechanical analysis for assessment of carbon fillers in glass fiber epoxy composites

“…The storage modulus of the nanocomposite with 5 wt% of GNP, in the glassy state, below T g is reported to be lower and in the rubbery state (above T g ), it is observed to be higher. Some authors 8 have emphasized the need for functionalization of graphene and its derivatives to augment the properties of the nanocomposites. In literature, 9,10 the effects of different polymer matrices, reinforcement and fillers on interfacial interactions are discussed based on DMA parameters.…”