Graphene-based polymer composites nanocomposites

Exceptional mechanical properties along with remarkable electronic transport properties and thermal conductivity have made graphene the best carbon filler. Significant enhancement in mechanical properties of graphene-based polymer nanocomposites has been found (even with lower concentration) compared to those of the neat polymer and conventional graphite-based composites. Moreover, graphene/polymer nanocomposites exhibit several-fold increase in electrical conductivity and thermal conductivity. The conductive networks formed by graphene sheets result in considerable increase of the electrical conductivity and thermal conductivity of nanocomposites. As can be observed in Tables 7.1 and 7.2, property enhancements vary... 

Saravanan, N., Rajasekar, R., Mahalakshmi, S., Sathishkumar, T.P., Sasikumar, K.S.K., Sahoo, S., 2014. Graphene and modified graphene-based polymer nanocomposites — A review. Journal of Reinforced Plastics and Composites 33, 1158—1180. 

Carbon-based polymer nano composites represent an interesting type of advanced materials with structural characteristics that allow them to be applied in a variety of fields. Functionalization of carbon nanomaterials provides homogeneous dispersion and strong interfacial interaction when they are incorporated into polymer matrices. These features confer superior properties to the polymer nanocomposites. This chapter focuses on nanodiamonds, carbon nanotubes and graphene due to their importance as reinforcement fillers in polymer nanocomposites. The most common methods of synthesis and functionalization of these carbon nanomaterials are explained and different techniques of nanocomposite preparation are briefly described. The performance achieved in polymers by the introduction of carbon nanofillers in the mechanical and tribological properties is highlighted, and the hardness and scratching behavior of the nanocomposites are also discussed. 

Recent studies showed that graphite nanoplatelets (GNP) or graphene could be used as a viable and inexpensive filler substitute for (3NTs (Fukushima and Drzal 2003). Typical values of the electrical percolation thresholds, which have been reported in the literature for graphene-based nanocomposites for selected polymer matrices, are presented in Table 13.3. The influence of graphene loading on the conductivity of one of the composites presented in Table 13.3 is shown in Fig. 13.2b. One can see that the electrical percolation thresholds achieved with graphene-based nanocomposites are often compared with those reported for CNT/polymer composites. 

In situ polymerisation of the polymer matrix is an attractive method of preparing graphene-based composites although often solvents are used to reduce the viscosity of the dispersions. For example, intercalative polymerisation of methyl methacrylate and epoxy resins has been achieved with graphene oxide to produce nanocomposites with enhanced properties. It has also been possible to use in situ polymerization produce polyethylene- and polypropylene-matrix graphene oxide nanocomposites. The technique of grafting poly(methyl methacrylate) chains onto graphene oxide has also been employed to make the filler compatible with the polymer matrix. " ... 

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