Effect of pre and Post-Dispersion on Electro-Thermo-Mechanical Properties of a Graphene Enhanced Epoxy

Abstract

Graphene nanoplatelet (GNP) modified epoxy nanocomposites are becoming attractive to aerospace due to possible improvements in their mechanical, electrical and thermal properties at no weight cost. The process of obtaining reliable material systems provides many challenges, especially at larger scale (a volume effect). This paper reports on the main fabrication stages of GNP-based epoxy composites, namely (i) pre-dispersion, (ii) dispersion, and (iii) post-dispersion. Each stage is developed to show the interest and potential it delivers for property enhancement. Chemical modification of GNP is presented; functionalisation by Triton X-100 shows elastic modulus improvements of the epoxy at low particle content (≤3%). The post-dispersion step as an alignment of GNP into the epoxy by an electrical field is discussed. The electrical conductivity is below the simulated percolation threshold and an improvement of the thermal diffusivity of 220% when compared to non-oriented GNP epoxy sample is achieved. The work demonstrates how the addition of functionalised graphene platelets to an epoxy resin will allow it to act as electrical and thermal conductor rather than as insulator

Tensile and flexural behaviour of a graphene/epoxy composite: experiments and simulation

“…These observations indicate weak interfacial interaction and it is expected to be the main damage that leads to ultimate fracture of the tested specimens [6].…”

“…The high stiffness and strength properties of graphene platelets have drawn extensive attention from researchers worldwide. A massive number of studies have been carried out to study the reinforcing effect of graphene in polymer matrices [1][2][3][4][5][6][7][8][9][10]. It has been reported though that the final mechanical properties of nanocomposites can be affected by various factors, such as the inherent properties of matrices and fillers, the shape, size, aspect ratio and volume fraction of fillers, the interaction between fillers and matrices creating an interphase, the composite's fabrication method, which can affect uniform dispersion, introduce voids and other imperfections and hence reduced performance.…”

“…The effect of graphene dispersion was investigated by Tang et al [2], while Wang et al [3] explored the effect of graphene nanoplatelet (GnP) size on tensile and flexural modulus and strength of a GnP/epoxy nanocomposite. The influence of the manufacturing parameters on the performance of a GnP/epoxy nanocomposite was studied in detail by Pullicino et al [5] and Poutrel et al [6]. The former examined the effect of shear mixing speed and time on mechanical properties, while the latter reported the effect of the functionalization of nanoparticles, as well as the alignment of GnPs into the epoxy by an electrical field on mechanical, electrical and thermal conductivity.…”

Transparent Surfactant/Epoxy Composite Coatings with Self‐Healing and Superhydrophilic Properties

“…The cross‐linking densities of the copolymers decreased from 1.66 × 10 3 to 0.886 × 10 3 mol m –3 with the raising of the percent of Triton X‐100. This is mainly due to the hydrogen bond formed between the hydroxyl group in the Triton X‐100 molecule and the ether group in the diglycidyl ether of bisphenol A (DGEBA), which forms a steric hindrance, hindering the reactions between DGEBA and the poly(propylene glycol) bis (2‐amino‐propyl) ether (D230) curing agent, thus lowering the cross‐linking density …”

“…This is mainly due to the hydrogen bond formed between the hydroxyl group in the Triton X-100 molecule and the ether group in the diglycidyl ether of bisphenol A (DGEBA), which forms a steric hindrance, hindering the reactions between DGEBA and the poly(propylene glycol) bis (2-amino-propyl) ether (D230) curing agent, thus lowering the cross-linking density. [28,29] To conclude, we hypothesize that the Triton X-100 molecules hindered the reactions between the epoxy group and the amino group in the curing agent, as shown in Figure 9. As a result, smaller amounts of curing agents reacted with the DGEBA.…”