The resistivity of the conductive composite varies as a function of the volume fraction of the conductive material.Considerable experimental and theoretical work has been done to examine how the volume fractions and t...The resistivity of the conductive composite varies as a function of the volume fraction of the conductive material.Considerable experimental and theoretical work has been done to examine how the volume fractions and the morphology of the components affect the electrical behavior of the composite materials.The generalized effective medium(GEM) equation gives the complete information on how the volume fraction of components may affect the medium conductivity by taking into an account the intrinsic conductivities and geometries of both components and also their arrangement and orientation in the applied electric fields.In this paper the electrical percolation phenomenon in CB/HDPE composite influenced by crosslinking under different irradiation doses and different ambient temperatures has been investigated.The experimental data regarding the dependence of conductivity on the volume fraction of CB were fitted into the GEM equation.The parameters in the GEM equation,corresponding to the dispersion characters of CB in HDPE matrix,were determined through the computer fitting.The CB particles aggregated constructing a three\|dimensional conducting network along the electrical current direction.The polymer matrix,however,is statistically vertical to electrical current direction, hindering conductive particles from contacting each other.The higher the irradiation dose or the ambient temperature,the more serious the hindrance.The electrical conductivity of HDPE composites filled with high\|structure CB particles is dominated by percolation mechanism based on a particle\|touching model,while crosslinking or ambient temperature increasing causes a larger gap between the conductive particles and makes the conductivity more affectd by tunneling mechanism.展开更多
A group of polyethylene\|carbon black (PE\|CB) composites was prepared with different CB volume fraction and the dependence of conductivity on the CB volume fraction was measured. The conductive percolation phenomenon...A group of polyethylene\|carbon black (PE\|CB) composites was prepared with different CB volume fraction and the dependence of conductivity on the CB volume fraction was measured. The conductive percolation phenomenon of those composites was studied by Monte Carlo method. It was supposed that the conduction of those composites was not only dependent on the contact pathway formation but also on the quantum mechanical tunnel formation. The put in particle number dependence of “the conductive conjunction” number and “the partial conducting pathway” number and “the average particle number” in the partial conducting pathway was showed in three figures, respectively. The typical CB particle conjunct states obtained by Monte Carlo method were illustrated with “the conductive conjunction”, “the partial conducting pathway”, and “the conducting pathway” in different marks. Thus it vividly demonstrates the internal reason for the conductive percolation of the PE\|CB composites. It is worth notice that only more than 50% CB particles are connected together to form the conducting pathway when the conductive percolation takes place, and that in the system there still exist some partial conducting pathways. The later does not make contribution for the conductivity of the PE\|CB composites.展开更多
文摘The resistivity of the conductive composite varies as a function of the volume fraction of the conductive material.Considerable experimental and theoretical work has been done to examine how the volume fractions and the morphology of the components affect the electrical behavior of the composite materials.The generalized effective medium(GEM) equation gives the complete information on how the volume fraction of components may affect the medium conductivity by taking into an account the intrinsic conductivities and geometries of both components and also their arrangement and orientation in the applied electric fields.In this paper the electrical percolation phenomenon in CB/HDPE composite influenced by crosslinking under different irradiation doses and different ambient temperatures has been investigated.The experimental data regarding the dependence of conductivity on the volume fraction of CB were fitted into the GEM equation.The parameters in the GEM equation,corresponding to the dispersion characters of CB in HDPE matrix,were determined through the computer fitting.The CB particles aggregated constructing a three\|dimensional conducting network along the electrical current direction.The polymer matrix,however,is statistically vertical to electrical current direction, hindering conductive particles from contacting each other.The higher the irradiation dose or the ambient temperature,the more serious the hindrance.The electrical conductivity of HDPE composites filled with high\|structure CB particles is dominated by percolation mechanism based on a particle\|touching model,while crosslinking or ambient temperature increasing causes a larger gap between the conductive particles and makes the conductivity more affectd by tunneling mechanism.
文摘A group of polyethylene\|carbon black (PE\|CB) composites was prepared with different CB volume fraction and the dependence of conductivity on the CB volume fraction was measured. The conductive percolation phenomenon of those composites was studied by Monte Carlo method. It was supposed that the conduction of those composites was not only dependent on the contact pathway formation but also on the quantum mechanical tunnel formation. The put in particle number dependence of “the conductive conjunction” number and “the partial conducting pathway” number and “the average particle number” in the partial conducting pathway was showed in three figures, respectively. The typical CB particle conjunct states obtained by Monte Carlo method were illustrated with “the conductive conjunction”, “the partial conducting pathway”, and “the conducting pathway” in different marks. Thus it vividly demonstrates the internal reason for the conductive percolation of the PE\|CB composites. It is worth notice that only more than 50% CB particles are connected together to form the conducting pathway when the conductive percolation takes place, and that in the system there still exist some partial conducting pathways. The later does not make contribution for the conductivity of the PE\|CB composites.
