Exfoliated graphite fillers

Chivrac F, Pollet E, Averous L (2009) Progress in nano-biocomposites based on polysaccharides and nanoclays. Mater Sci Eng R Rep 67(1) 1-17 Crosthwaite JM, Aid SNVK, Maginn EJ, Brennecke JF (2004) Liquid phase behavior of imidazolium-based ionic liquids with alcohols. J Phys Chem B 108(16) 5113-5119 De Silva RT, Pasbakhsh P, Goh KL, Chai S-P, Ismail H (2013) Physico-chemical characterisation of chitosan/halloysite composite membranes. Polym Testing 32(2) 265-271 Debelak B, Lafdi K (2007) Use of exfoliated graphite filler to enhance polymer physical properties. Carbon 45(9) 1727-1734... 

B. Debelak and K. Lafdi, Use of exfoliated graphite filler to enhance polymer physical properties. Carbon, 45(9) 1727-1734, August 2007. 

For carbon nanotubes, discussed in detail in Chapter 10, conductivity is achieved at lower loadings (by weight) but these materials are difficult to disperse in molten polymers. Methods of surface functionalization and lower cost manufacturing must be developed before carbon nanotubes will find wider use as conductive fillers [52, 53]. As an alternative to nanotubes, Fukushima and Drzal [54] have observed conductivity thresholds of less than 3 vol% in composites containing acid-etched or othervdse functionalized exfoliated graphite. These composites retain or improve upon their mechanical properties compared to other carbon-filled polymers. 

New generadon nano scale fillers are challenging the domination of traditional fillers such a as carbon blacks and silica in the rubbery industry. Nanoscaled fillers such as layered sihcates, carbon nanotubes, carbon nanofibers (CNFs), exfoliated graphite, spherical particles and Polyhedral oligomeric silsesquioxane (POSS), etc., dispersed as a reinforcing phase in a mbber matrix are emerging as a relatively new form of usefiil material. 

Recent developments in polymer nanotechnology include the exfoliated clay nanocomposites, CNTs, carbon nanofibers, exfoliated graphite, nanocrystalline metals, and a host of other filler modified composite materials. Polymer matrix-based nanocomposites with exfoliated clay are discussed in this section. Performance... 

Another study pointed out the effects of multiple carbon fillers on the electrical and thermal conductivity of polycarbonate-based resins (King et al. 2012). Three different carbon fillers (carbon black [CB], carbon nanotubes [CNTs], and exfoliated graphite nanoplatelets [GNPs]) were analyzed via three different combinations of two different fillers (CB/CNT, CB/GNP, and CNT/GNP). In the case of the single fillers, a statistically significant increase was noticed at the 95% confidence level in composite electrical and thermal conduction. But too many filler interactions statistically impacted the composite electrical and thermal conductivity. 

Electrospinning composite nanofiber with graphite filler reported. Thin graphite nanoplatelets synthesized by an intercalation / exfoliation process incorporated into nanofibers on electrospinning. 

Exfoliating layered particles such as the clays, mica, or graphite is being used to provide very effective reinforcement of polymers at loading levels much smaller than in the case of solid particles such as carbon black and silica.77 81 Other properties can also be substantially improved, including increased resistance to solvents, and reduced permeability and flammability. A number of such studies specifically address the effects of introducing layered fillers into polysiloxanes 42,82 88... 

The percolation is usually very low, such as less than 1%. However, the polymers for electronics require high conductivity, thus a much higher content of filler is desired to form highly conductive networks in polymer matrix. Moreover, a good dispersion also helps to achieve percolation at low volume fraction of fillers. The graphene-polymer composites that were prepared via complete exfoliation of graphite and molecular-level dispersion of... 

---