Polymer/graphite nanocomposites mechanical properties

Jiang X, Drzal LT (2010) Multifunctional high density polyethylene nanocomposites produced by incorporation of exfoliated graphite nanoplatelets 1 morphology and mechanical properties. Polym Compos 31 1091-1098... 

It is necessary to disperse the nanomaterials in the best possible manner, especially those layered structures such as graphite, graphene or clays. It is important to obtain very thin (ca. one nanometer) and very wide (ca. 500 nanometers) nanostructures dispersed in the polymer matrices to achieve optimal gas permeability and to improve their mechanical properties without affecting structural quality, using a small amount of the nanomaterial. The particle orientation also has an important effect on the properties of the nanocomposite. Nanoparticles need to be dispersed within the polymer so that are parallel to the material s surface. This condition ensures a maximum tor-... 

The main reason for the recent popularity of nanotechnology is that the reduction of the dimensions of a material to nanosize leads to new specific properties [82]. It is crucial to understand the intrinsic mechanical properties of CNFs in order to incorporate them into polymer resins to fabricate CNFs-reinforced nanocomposites. Because of the structural complexity of CNFs derived from variations in inner and outer wall thickness, cone angle, orientation of graphite plane, and C-C bonds, determination of their mechanical properties had posted considerable difficulties. To date, direct measurement of tensile properties of CNFs is accessible only with the aid... 

Carbon nanotubes are one-dimensional carbon materials with high aspect ratio (greater than 1000) and excellent mechanical, electrical, and thermal properties when compared to other carbon materials, such as graphite and fuUerene. CNT is one of the most promising filler for nanocomposites and have generated great interests in the polymer industry due the technical applications in electrical conductivity, thermal conductivity, and improvements in mechanical properties (Choi et al. 2014). 

Mechanical, electrical, and thermal properties of polymer/graphite/graphene nanocomposites are described in this section. 

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... 

Sometimes it is necessary to have more than one material in nanofibers to mimic the structural and mechanical properties of the natural extracellular matrix. This can be done by a process called co-electrospinning, whereby blends of two different materials are electrospun to fabricate the scaffolds. Depending on the application one can make blends of different polymers or proteins or a combination of both. In our laboratory we have carried out extensive work on nanocomposite nanofibers fabricated from carbon nanotubes (CNTs). CNTs are a layer of graphite, one atom thick, rolled into a cylinder. CNT has a Young s modulus in the order of 1 TPa. " The toughness of CNT ranges from 6 to 30%. Incorporation of CNTs in polymeric and/or protein scaffolds not only improves the mechanical properties but gives unique electrical conductivity as well. We have fabricated co-electrospun scaffolds from various proteins, polymers and CNT. 

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