*2.14.4 Thermal conductivity*

All electronic units produce excessive heat and thus demand thermal management to prevent premature failure. Thermal management is crucial for the efficiency of


*PVA, Poly(vinyl alcohol); PVA/GO, poly(vinyl alcohol)/graphene oxide; PVA/RGO, poly(vinyl alcohol)-reduced graphene oxide.*

#### **Table 1.**

*Resistance, resistivity and conductivity of the nanocomposites [108].*

**Figure 8.** *Thermal degradation temperatures PP/GO nanocomposites [114].*


#### **Table 2.**

*Thermal degradation temperatures PP/GO nanocomposites [114].*

advanced integrated circuits (ICs) and high-frequency high-power density communication devices. Recently, the use of high-conductivity materials is suggested for electronic cooling and for improving the heat dissipated from chips. The cost of highconductivity materials is of major concern. Therefore, there is a real need for low-cost high-thermal conductivity materials and efficient design to integrate these materials into electronic devices. Graphene has drawn tremendous attention for heat dissipation due to its extraordinarily high in-plane thermal conductivity (2000–4000 Wm<sup>1</sup> K<sup>1</sup> ) compared to copper (400 Wm<sup>1</sup> K<sup>1</sup> ). The thermal conductivity of graphene has become an important research topic and is attracting tremendous interest in the area of thermoelectric waste heat recovery. The thermal conductivity of graphene is related to its low mass and the strong bond of carbon atoms [119].

#### *2.14.5 Gas barrier*

Graphene and its derivatives have been considered promising nanoscale fillers in the gas barrier application of polymer nanocomposites (PNCs). The breakthrough of gas into polymer films has limited their performance. The barrier properties of polymers can be greatly improved by loading impermeable lamellar fillers with a high aspect ratio to change the diffusion path of gas-penetrant molecules, such as graphene. *Graphene Reinforced Polymer Matrix Nanocomposites: Fabrication Method… DOI: http://dx.doi.org/10.5772/intechopen.108125*

**Figure 9.**

*Illustration of the 'tortuous pathway' (a) In a polymer matrix before adding graphene nanoparticles (b) In nanocomposite after adding the graphene nanoparticles [120].*

As a result of the nanofillers, diffusing molecules take longer and more tortuous paths to pass through the nanocomposite film, resulting in a considerable decrease in permeability as shown in **Figure 9**. The gas barrier performance of PNCs is determined by mainly three factors: filler properties (resistance to gas diffusion, aspect ratio and volume fraction), the intrinsic barrier property of the polymer matrix, and the 'quality' of dispersion (agglomeration/specific interface, free volume generated by mediocre interface management and the texture/orientation of filler platelets). The levels of exfoliation of the layered nanofillers in the polymer matrix are crucial to the successful development of PNCs [121].
