Conductivity percolation of carbon nanotubes (CNT) in polystyrene (PS) latex film

In this study, the effect of multiwalled carbon nanotubes (MWNT) on film formation behaviour and electrical conductivity properties of polystrene (PS) latex film was investigated by using the photon transmission technique and electrical conductivity measurements. Films were prepared by mixing PS latex with different amounts of MWNTs, varying in the range between 0 and 20 wt%. After drying, MWNT content films were separately annealed above the glass transition temperature (Tg) of PS, ranging from 100 to 270 °C, for 10 min. To monitor film formation behavior of PS–MWNT composites, transmitted light intensity, Itr, was measured after each annealing step. The surface conductivity of annealed films at 170 °C was measured and found to increase dramatically above a certain fraction of MWNT (4 wt%) following the percolation theory. This fraction was defined as the percolation threshold of conductivity, Rc. The conductivity scales with the mass fraction of MWNT as a power law with exponent 2.27, which is extremely close to the value of 2.0 predicted by percolation theory. In addition, the increase in Itr during annealing was explained by void closure and interdiffusion processes. Film formation stages were modeled and the corresponding activation energies were measured.

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Electrical Conductivity and Elastic Properties of MWCNT-PP Nanocomposites

Volume 13: Nano-Manufacturing Technology; and Micro and Nano Systems, Parts A and B ◽

10.1115/imece2008-68431 ◽

2008 ◽

Author(s):

Yves Ngabonziza ◽

Jackie Li ◽

Carol F. Barry

Keyword(s):

Carbon Nanotubes ◽

Electrical Conductivity ◽

Percolation Threshold ◽

Elastic Properties ◽

Percolation Theory ◽

Injection Rate ◽

Multiwalled Carbon ◽

Injection Speed ◽

Nanocomposite System ◽

Injection Molded

Electrical and elastic properties of multiwalled carbon nanotubes (MWCNTs) reinforced polypropylene (PP) nanocomposites were studied experimentally and theoretically. The MWCNT-PP nanocomposites samples with a range of 0 to 12 wt% MWCNT were injection molded using different injection velocities. These nanocomposites were characterized for their electrical resistance using 2-Probe measurement and their tensile properties. Parallel to the experimental investigation, a percolation theory was applied to study the electrical conductivity of the nanocomposite system in terms of content of nanotubes and injection rate. Both Kirkpatrick [1] and McLachlan [2] models were used to determine the transition from low conductivity to high conductivity which designates as percolation threshold. Both experimental and modeling results have shown that the electrical conductivity increased suddenly as the content of MWNTs was close to percolation threshold of 3.8 wt%. The injection speed also showed an effect on electrical conductivity of the composites. In addition, several micromechanical models were applied to elucidate the elastic properties of the nanocomposites. The results indicate that the interphase between the carbon nanotubes and polymers plays an important role in determining elastic modulus of the system.

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CNT Reinforced Silver Nanocomposites: Mechanical and Electrical Studies

Journal of Materials ◽

10.1155/2016/8629206 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Dinesh Kumar ◽

Sonia Nain ◽

Neena ◽

Hemant Pal ◽

Ravi Kumar

Keyword(s):

Carbon Nanotubes ◽

Electrical Conductivity ◽

Elastic Modulus ◽

Multiwalled Carbon Nanotubes ◽

Multiwalled Carbon ◽

Electrical Studies ◽

Silver Nanocomposites ◽

Silver Matrix ◽

Nanoindentation Hardness

Nanoindentation hardness and elastic modulus of the silver/MWCNT (multiwalled carbon nanotubes) composites, fabricated by modified wet mixing technique, are studied in the present work. CNT reinforced silver nanocomposites, fabricated by introducing 4.5 volume percentages of CNT in the silver matrix, have increased elastic modulus and approximately 50% higher hardness than pure nanosilver. It is also observed from the results that the electrical conductivity of the fabricated materials was decreased by increasing the CNTs volume %.

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