Composite membranes with polyvinyl alcohol (PVA),sulphonated poly ether ether ketone (SPEEK) and phosphotungstic acid (PWA) were prepared using solvent casting method.The proton conductivities of such membranes were f...Composite membranes with polyvinyl alcohol (PVA),sulphonated poly ether ether ketone (SPEEK) and phosphotungstic acid (PWA) were prepared using solvent casting method.The proton conductivities of such membranes were found to be in the order of 10^(-3) S/cm in the fully hydrated condition at room temperature as measured by impedance spectroscopy.The crystalline properties were studied by X-ray diffraction analysis.The thermal properties were determined by TGA and DSC techniques.The tensile strength and perce...展开更多
The study on the correlation between electrical percolation and viscoelastic percolation for carbon black（CB） filled high-density polyethylene（HDPE） conductive composites was carried out through examining the fill...The study on the correlation between electrical percolation and viscoelastic percolation for carbon black（CB） filled high-density polyethylene（HDPE） conductive composites was carried out through examining the filler volume fraction dependence of the volume resistivity（ρ） and normalized dynamic storage modulus,G c/G p,in which G c,G p are dynamic storage modulus of the composites and the matrix respectively. The results revealed that the critical filler volume fraction of viscoelastic percolation approached the lower threshold（φ1） of the electrical percolation,indicating an insulator-semiconductor change corresponding to the beginning of network structure formation. Substituting K for A,a modified Kerner-Nielson equation was obtained and used to analyze the formation of network structure. It is suggested that parameter K is associated with CB volume fraction. [WT5HZ]展开更多
The study on the correlation between time dependence of electrical resistivity and dynamic storage modulus for carbon black(CB) filled polymer composites was carried out. With the increase of the dynamic storage modul...The study on the correlation between time dependence of electrical resistivity and dynamic storage modulus for carbon black(CB) filled polymer composites was carried out. With the increase of the dynamic storage modulus(G′) as well as the normalized dynamic storage modulus(G′_ c /G′_ p), the volume resistivity(ρ) deceases with the increase of annealing time beyond the T_ m of the composites. It is believed that this phenomenon can be used for examining the development of agglomerate structure of filled composites and illustrating the micro-mechanism of the NTC behavior. It is assumed that melting treatment to CB filled composites results in a higher modulus and lower resistivity due to more even local dispersion of the particles and formation of perfect CB network structure within the matrix.展开更多
基金supported by the Department of Science and Technology,India (SR/FTP/CS-33/2005 dated 11-08-2005).
文摘Composite membranes with polyvinyl alcohol (PVA),sulphonated poly ether ether ketone (SPEEK) and phosphotungstic acid (PWA) were prepared using solvent casting method.The proton conductivities of such membranes were found to be in the order of 10^(-3) S/cm in the fully hydrated condition at room temperature as measured by impedance spectroscopy.The crystalline properties were studied by X-ray diffraction analysis.The thermal properties were determined by TGA and DSC techniques.The tensile strength and perce...
文摘The study on the correlation between electrical percolation and viscoelastic percolation for carbon black（CB） filled high-density polyethylene（HDPE） conductive composites was carried out through examining the filler volume fraction dependence of the volume resistivity（ρ） and normalized dynamic storage modulus,G c/G p,in which G c,G p are dynamic storage modulus of the composites and the matrix respectively. The results revealed that the critical filler volume fraction of viscoelastic percolation approached the lower threshold（φ1） of the electrical percolation,indicating an insulator-semiconductor change corresponding to the beginning of network structure formation. Substituting K for A,a modified Kerner-Nielson equation was obtained and used to analyze the formation of network structure. It is suggested that parameter K is associated with CB volume fraction. [WT5HZ]
文摘The study on the correlation between time dependence of electrical resistivity and dynamic storage modulus for carbon black(CB) filled polymer composites was carried out. With the increase of the dynamic storage modulus(G′) as well as the normalized dynamic storage modulus(G′_ c /G′_ p), the volume resistivity(ρ) deceases with the increase of annealing time beyond the T_ m of the composites. It is believed that this phenomenon can be used for examining the development of agglomerate structure of filled composites and illustrating the micro-mechanism of the NTC behavior. It is assumed that melting treatment to CB filled composites results in a higher modulus and lower resistivity due to more even local dispersion of the particles and formation of perfect CB network structure within the matrix.
