Electrical, mechanical, and crystallization properties of ethylene‐tetrafluoroethylene copolymer/multiwalled carbon nanotube composites

Abstract

Multiwalled carbon nanotubes (MWCNTs) were melt‐mixed in a conical twin‐screw extruder with a random copolymer of ethylene and tetrafluoroethylene. Surprisingly, the electrical percolation threshold of the resultant composites was quite low; ∼0.9 wt %. In fact, this value is as low or lower than the value for most MWCNT/semicrystalline polymer composites made with roughly equivalent aspect ratio tubes mixed in a similar manner, for example, melt mixing. This low percolation threshold, suggestive of good dispersion, occurred even though the polymer surface energy is quite low which should make tubes more difficult to disperse. Dynamic mechanical measurements confirmed the rather low percolation threshold. The effect of nanotubes on crystallization kinetics was quite small; suggesting perhaps that a lack of nucleation which in turn reduces/eliminates an insulating crystalline polymer layer around the nanotubes might explain the low percolation threshold. Finally, the modulus increased with the addition of nanotubes and the strain at break decreased. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41052.

Morphology of polystyrene/poly(methyl methacrylate) blends: Effects of carbon nanotubes aspect ratio and surface modification

“…Due to their excellent mechanical properties as well as high electrical and thermal conductivities, carbon nanotubes (CNTs) have been widely investigated in the field of material science and engineering . For polymer blends, CNTs have been widely studied with respect to their location in the blends as well as their effect on the domain size and shape .…”

Simulations on polymer nanocomposite crystallization

“…The crystallization behavior of random copolymer nanocomposites is also an interesting research topic. Similar to homopolymer nanocomposites, the addition of nanofillers in random copolymers can also promote the crystallization process and accelerate the crystallization rate 107–109 . For example, Verma and Choudhary 107 investigated the crystallization process of PP random copolymers under isothermal conditions in presence of multiwalled carbon nanotubes (MWCNT), and found that MWNT lowers the nucleation barrier, thereby accelerating the crystallization process.…”

“…Similar to homopolymer nanocomposites, the addition of nanofillers in random copolymers can also promote the crystallization process and accelerate the crystallization rate. [107][108][109] For example, Verma and Choudhary 107 investigated the crystallization process of PP random copolymers under isothermal conditions in presence of multiwalled carbon nanotubes (MWCNT), and found that MWNT lowers the nucleation barrier, thereby accelerating the crystallization process. In addition, for the random copolymer nanocomposite systems, the crystallization behavior and crystal morphology also depend on the content of non-crystallizable comonomers.…”