Polymer nanocomposites are unique materials reinforced with nanoscale additives. Among a variety of nanomaterials available to act as filler additives in different polymer matrices, graphene is the most versatile one. Graphene-based polymer nanocomposites have improved electrical, mechanical, chemical, and thermal properties, which make them suitable for applications in the electronics, energy, sensor, and space sectors. Graphene, the nanosized filler, can be prepared using either a top-down or a bottom-up approach and dispersed in the polymer matrix utilizing different conventional techniques. The nanocomposite materials find usage in suitable area of applications depending on their specific characteristics. This chapter discusses the current state-of-the-art manufacturing techniques for graphene and graphene-based nanocomposite materials. Application of graphene-based polymer nanocomposites in the various fields with an emphasis on the areas high heat flux applications requiring enhanced thermal conductivity will be an additional major focus of this chapter.
TopIntroduction
Since its discovery in the early twenty-first century (Novoselov 2004), graphene has been dominating the research and development sector of the materials world. The worldwide interest in graphene is clearly exhibited by the rapidly increasing number of publications in different format of available literatures (Figure 1). A Web of Science database topic search on graphene resulted in approximately 34000 published documents only in 2018, compared to the same of 2342 in 2009. This rapid growth in interest within last ten years can easily be attributed to the unique properties of graphene and versatile applications of graphene-based nanomaterials. The sp2 hybridized carbon atoms, arranged in a honeycomb lattice, impart excellent electrical, thermal, optical and mechanical properties to the 2D nanostructure, named graphene. While Balandin et al predicted the high thermal conductivity (~5000 Wm-1K-1),(Balandin, 2008) Lee and coworkers have shown extremely high mechanical strength of monolayer graphene (Young’s modulus of ~ 1 TPa). (Lee, 2008) In their work published in Applied Physics Letters, Moser et al demonstrated extremely high current density of monolayer graphene, which is in the order of 108 A/cm2.(Moser, 2007) Moreover, monolayer graphene exhibits 97.7% transmittance. (Nair, 2008) By virtue of such properties, graphene has found its usefulness in a wide variety of application areas. However, graphene is reaching the consumer market in a variety of finished end products suitable for different applications. One of the major areas of graphene application is in the field of nanocomposites. In this chapter, we will be focused on application of graphene in polymer nanocomposites.
Figure 1. Rapid increment of graphene-related publications
Nanocomposites are heterogenous materials reinforced with nanofiller additives. They exhibit enhanced mechanical, electrical, thermal and chemical properties. With rapid growth of nanotechnology, nanocomposites are also finding applications in different industrial sectors including electronics, packaging, energy, biomedicine and many more. In recent years, research in this field has been increased significantly. A similar Web of Science article search resulted in data that demonstrates rapid increment in publication within last 10 years (Figure 2a). Polymer nanocomposites are distinguished from regular composites by the fact that they have nanofiller additives incorporated in the polymer matrix. Graphene has the unique ability to be incorporated and used in versatile application fields utilizing nanocomposites, which cannot be achieved by any other nanofiller additives. Such nanocomposites are emerging as extremely useful materials featured in a stupendously growing number of publications every year (Figure 2b). According to the Web of Science, last year 3795 articles were published in different journals including the topic of graphene-based polymer nanocomposites. In this chapter, we are going to discuss application of graphene-based polymer nanocomposites, including electronics, thermal management and structural applications.