Carbon nanostructures via adding to a polymer matrix, while improving the electrical, mechanical and optical properties of the nanocomposites, are widely used in the industry, medicine, and agriculture. The authors presented several investigations on a new type of gamma dosimeter based on the polymer-carbon nanostructures nanocomposite. In this research, the electrical percolation threshold of the Polystyrene-Graphene Oxide nanocomposite (PS/GO) was simulated using the finite element method in different weight percentages. Then, at the experimental phase, various nanocomposites were fabricated in different weight percentages of 0. 05, 0. 1, 0. 5, 1, 2, 3, 5 and 8 via the mixed-solution process. The electrical conductivities of the samples were measured at the room temperature. Finally, the electrical conductivities of the nanocomposites were compared using the FEM simulation and the experimental results, which were estimated as 2. 5wt%. The results of this study showed that the finite element method in accordance with the experimental results is a powerful tool to determine the electrical properties of the polymer nanocomposites considering the dosimetric approaches.

In the present research, the reinforcement effect of vapor grown carbon nanofiber (VGCNF) was studied in relation to the mechanical properties and electrical conduction behavior of fabricated nanocomposites. Different weight fractions of nanofillers into epoxy resin, from 0.05 to 1 wt% and up to 2 wt% for mechanical and electrical properties were investigated. It was found that the optimum improvement in mechanical properties of nanocomposite is obtained at 0.25 wt% of carbon nanofibers. At this filler content, 23% enhancement in tensile strength and 10% in flexural strength have been observed. The degree of the VGCNF dispersion has been monitored by means of viscosity variation of the suspension during the sonication process to obtain the optimum sonication time. Finally, the quality of the dispersion for post-cured nanocomposites is characterized by fractured surfaces using the scanning electron microscopy. Agglomerates had a direct effect on the reduction of tensile and flexural strength of nanocomposites. The electrical conductivity was obtained by means of surface measuring method. The optimum amount of filler for the generation of a fine electrical conductivity was found to be around 0.5 wt% of VGCNF. After the threshold point, the electrical conductivity of nanocomposites was slightly raised in spite of adding more filler contents.

The cyclicvoltammetry method was utilized for the determination of percolation threshold of electroactivity of polyvinylchloride (PVC) and doped polyaniline through sulphosalicylic, acid (SSA) blend. The blends were prepared from N-methylpyrrolidone (NMP) solutions and PVC/PANI-SSA blend with weight fractions from 0.1 to 0.006 of polyaniline. The films from the blends were provided by. casting the above polymer solutions on a GC electrode. Voltammograms were recorded by using a one-compartment cell fitted with a GC as working electrode, Pt as auxiliary electrode and SCE as reference electrode, in 1M perchloric acid electrolyte solution. The obtained results from cyclicvoltammetry showed that PANI-SSA/PVC on and above 0.008 percent weight from polyaniline is electroactive.

areview study is presented in relation to polymer/graphene nanocomposites. The research works have shown that the graphene can be considered as the strongest material and the hummer’ s method is a suitable method for its production. Functionalization by chemical groups compatible with its matrix can enhance dispersion of the nanoparticles within it. The effect of graphene nanoplatelets on the isothermal and non-isothermal crystallization behavior, nucleation and crystal growth is explained. Several contradicting results including both increase and decrease in crystallinity have been reported. The change of electrical conductivity with the addition of graphene and method of determining percolation threshold are presented. The results showed a significant increase in electrical conductivity by incorporation of graphene nanosheets. The mechanical properties of nanocomposites including elastic modulus, elongation-at-break and tensile strength are reviewed. The reported results revealed that modulus increased due to higher modulus of nanoparticles and there was a contradictory result for tensile strength and elongation-at-break. Functionalization of nanosheets could increase the tensile strength of nanocomposites through stronger adhesion between filler and matrix. The thermal conductivity of these nanocomposites and the desirable method for measurement of thermal conductivity constant are discussed. The results showed that graphene nanoplatelets are less effective in enhancing thermal conductivity in comparison to electrical conductivity. The rheological properties of nanocomposites were affected by addition of nanosheets and the obtained rheological percolation threshold was different from the electrical one. The lower electrical percolation in comparison to rheological one means electrical threshold is obtained from direct contact of nanoparticles.

Simultaneous capillary dominated displacement of the wetting and non-wetting phases are processes of interest in many disciplines including modeling of the penetration of polluting liquids in hydrology or the secondary migration in petroleum reservoir engineering. Percolation models and in particular invasion percolation is well suited to characterize the slow immiscible displacement of two fluids when both the gravity and viscous effects are negligible. In particular, the characteristic of the percolating cluster and the other important percolation properties at the breakthrough can be inferred. However, with the inclusion of the gravity forces, the behavior may change. For example, as the magnitudes of the gravity forces are comparable to the capillary forces, we have observed a transition in the structure of the interface (i.e. invasion front) depending on the dimensionless Bond number (i.e. ratio of gravity to capillary forces).We have taken a numerical study of the displacement of two immiscible fluids in the presence of the gravity force in a network of random pores. The main contribution is to investigate the effect of heterogeneity by considering various throat size distributions. We consider the injection to take place from one side of the system and displace the displaced fluid from the other side. The condition of the stability or instability of the front (or interface) is observed to be dependent on the dimensionless bond number as well as the heterogeneity of the system.