Thermal Diffusivity Mapping of Graphene Based Polymer Nanocomposites

Abstract

Nanoparticle dispersion is widely recognised as a challenge in polymer nanocomposites fabrication. The dispersion quality can affect the physical and thermomechanical properties of the material system. Qualitative transmission electronic microscopy, often cumbersome, remains as the ‘gold standard’ for dispersion characterisation. However, quantifying dispersion at macroscopic level remains a difficult task. This paper presents a quantitative dispersion characterisation method using non-contact infrared thermography mapping that measures the thermal diffusivity (α) of the graphene nanocomposite and relates α to a dispersion index. The main advantage of the proposed method is its ability to evaluate dispersion over a large area at reduced effort and cost, in addition to measuring the thermal properties of the system. The actual resolution of this thermal mapping reaches 200 µm per pixel giving an accurate picture of graphene nanoplatelets (GNP) dispersion. The post-dispersion treatment shows an improvement in directional thermal conductivity of the composite of up to 400% increase at 5 wt% of GNP. The Maxwell-Garnet effective medium approximation is proposed to estimate thermal conductivity that compare favourably to measured data. The development of a broadly applicable dispersion quantification method will provide a better understanding of reinforcement mechanisms and effect on performance of large scale composite structures.

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

“…The nanoparticles exhibited an average thickness of 6-8 nm, an average length of 25 μm and a typical surface area of 120-150 m 2 g −1 . The graphene characteristics were obtained by independent experimental studies, as presented in [5,24]. The nanoparticles were combined with a polymeric matrix based on a low-viscosity bisphenol-A epoxy resin (Araldite LY564) and a cycloaliphatic polyamine curing agent (Aradur 2954) with a mixing ratio of 100:35 (epoxy: hardener) supplied by Huntsman [25].…”

Infrared thermography for void mapping of a graphene/epoxy composite and its full‐field thermal simulation

“…Recently, Gresil et al presented a quantitative dispersion characterisation method using noncontact infrared thermography (IRT) mapping that measured the thermal diffusivity of graphene polymer nanocomposites and related the thermal diffusivity to a dispersion index. It was suggested by the authors that the method is capable to evaluate dispersion over a large area at reduced effort and cost with an actual resolution of this thermal mapping reaching 200 μm per pixel.…”

Graphene in aerospace composites: Characterising thermal response

“…At first, two graphene/polymer nanocomposite structures were studied. The first one is the Graphene/PA-6 composite studied by K. Chu et al [24] and the second one is GnP/epoxy composite manufactured by our research group [29]. The material properties assumed in each case are summarised in Table 1…”

“…Numerical results are compared with analytical and experimental data found in literature and measured by our research group. Particularly, the model was used to simulate the steady behaviour of graphene/PA-6 [24] and GnP/epoxy systems [29].…”