Electrical, rheological, and mechanical properties copolymer/carbon black composites

Abstract

This work aims to evaluate the electrical conductivity and the rheological and mechanical properties of copolymer/carbon black (CB) conductive polymer composites (CPCs). The copolymers, containing ethylene groups in their structure, used as matrix were polyethylene grafted with maleic anhydride (PEgMA), ethylene‐methyl acrylate–glycidyl methacrylate (EMA‐GMA), and ethylene‐vinyl acetate (EVA). For comparison purposes, bio‐based polyethylene (BioPE)/CB composites were also studied. The electrical conductivity results showed that the electrical percolation threshold of BioPE/CB composite was 0.36 volume fraction of CB, whereas the rheological percolation threshold was 0.25 volume fraction of CB. The most conductive CPC was BioPE/CB. Among the copolymer/CB CPCs, PEgMA/CB showed the highest conductivity, which can be attributed to the fact that the PEgMA copolymer had higher crystallinity. It also has a higher amount of ethylene groups in its structure. Torque rheometry analysis indicated that EMA‐GMA copolymer may have reacted with CB. Rheological measurements under oscillatory shear flow indicated the formation of a percolated network in BioPE/CB and copolymer/CB composites. Morphology analysis by scanning electron microscopy (SEM) indicated the formation of a percolated network structure in BioPE/CB composite and finely dispersed CB particles within the PEgMA copolymer. Wetting of CB particles/agglomerates by the copolymer matrix was observed in EVA/CB and EMA‐GMA/CB composites. Conductive CB acted as reinforcing filler as it increased the elastic modulus and tensile strength of BioPE and the copolymers.

Percolation Threshold and Depression in Properties of Polymer Nanocomposites

“…Despite the different changes in the material during the occurrence and increase of the percolation state, electrical conductivity is one of the most characteristic properties that can be observed and measured when adding conductive nanoparticles to a dielectric matrix. This happens because the incorporation of conductive nanoparticles increases the probabilities of conductive path formation 15 until it reaches a critical value and the nanocomposite changes from dielectric to dissipative or conductive, which is also indicated as the percolation threshold [16][17][18][19][20][21][22][23][24] . Moreover, the state of percolation in nanocomposites also presents changes on mechanical properties, which can be enhanced with low volume fractions of nanoparticles 25 or present discontinuities, caused by local perturbations on polymer chains, leading to a degradation mechanism of mechanical properties 8 .…”

Tailoring Nylon 6/Acrylonitrile-Butadiene-Styrene Nanocomposites for Application against Electromagnetic Interference: Evaluation of the Mechanical, Thermal and Electrical Behavior, and the Electromagnetic Shielding Efficiency

“…Such behavior can be attributed to the increased friction between the polymer matrix and the conductive charge, which restricts molecular movement in the polymer matrix [ 48 ]. Accordingly, the material has less fluidity, becoming more rigid and behaving like an elastic solid [ 49 , 50 ]. According to reports in the literature [ 51 , 52 ], the preferential location of carbon nanotubes can affect the viscosity in multicomponent polymeric materials.…”

Heat transfer prediction during curing of thick part of unsaturated polyester resin containing nanoparticles of graphene oxide and modified graphene oxide

“…1 GO consists of oxygen functional groups attached to the carbon plane, which makes it hydrophilic and allows it to disperse in polar solvents. 2,3 Particles are used in polymers to improve their physical-mechanical properties, [4][5][6] thermal properties, [7][8][9] electrical conductivity, 10 and flame retardancy. [11][12][13] Therefore, the use of particles to improve the properties of unsaturated polyester resins (UPR) has always been the focus of researchers, because of their various industrial applications.…”

“…Particles are used in polymers to improve their physical‐mechanical properties, 4–6 thermal properties, 7–9 electrical conductivity, 10 and flame retardancy 11–13 . Therefore, the use of particles to improve the properties of unsaturated polyester resins (UPR) has always been the focus of researchers, because of their various industrial applications.…”