Mono‐filler and bi‐filler composites based on thermoplastic polyurethane, carbon fibers and carbon nanotubes with improved physicomechanical and engineering properties

Abstract

Two types of carbon-based fillers, i.e. multi-walled carbon nanotubes and carbon fibers, were incorporated into thermoplastic polyurethane (TPU) through melt mixing to prepare mono-filler and bi-filler composites. It was evaluated as to how much the properties of bi-filler composites were different from those of their mono-filler counterparts. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) and time sweep rheological measurements were employed to study the microphase separation of TPU. The quantitative results of ATR-FTIR corroborated that the bi-filler composites possessed greater microphase separation compared to their mono-filler counterparts. The kinetics of networks formed by microphase separation was accelerated for the composite samples compared to neat TPU. The fillers acting as platforms provided a suitable surface for the hard segments to form microphase-separated domain networks. Conductivity measurement proved that the electrical conductivity values of the bi-filler composites were higher than those of the mono-filler counterparts and the simultaneous presence of fillers decreased the electrical percolation threshold. Moreover, the effect of shear deformation applied during the processing on the rheological and electrical properties of the mono-filler and bi-filler composites was evaluated. It was found that shearing at low rates increased the cross-time of G 0 and G 00 , and vice versa. Shearing at an intermediate rate of 20 s −1 promoted the electrical conductivity of both mono-filler and bi-filler composites and coherently decreased the electrical percolation threshold.

Effective Conductivity of Carbon-Nanotube-Filled Systems by Interfacial Conductivity to Optimize Breast Cancer Cell Sensors

“…In this section, the impacts of various parameters on the CNT network percentage after the percolation threshold (f) is met are explained. Figure 3 displays the variation of "f" at different "Lc" values based on Equation (17). A low "Lc" caused a high "f", but "f" reduced considerably at a high "Lc".…”

“…Carbon nanotubes (CNTs) endow significant conductivity and high mechanical properties to composites, especially polymer CNT nanocomposites (PCNT) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. A CNT aspect ratio in a range of 500–1000 creates a conductive network at extremely low concentrations of CNTs [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ].…”

Physico–mechanical properties of poly(ethylene‐co‐vinyl acetate)/acrylonitrile‐butadiene rubber/multi‐walled carbon nanotubes nanocomposites

“…There are numerous reports about the physico-mechanical properties of single-walled (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) filled polymer systems. [6][7][8][9][10][11][12][13][14][15][16][17][18][19] Razavi-Nouri [6,7] studied the effect of SWCNTs on dynamic mechanical properties and non-isothermal crystallization kinetics of polypropylene (PP). It was found that the maximum storage modulus (G') was obtained for the material containing 1 wt% SWCNTs.…”

“…Rostami et al have worked on the systems based on a thermoplastic polyurethane (TPU) reinforced with MWCNTs, [ 15 ] hybrid of functionalized graphene nanoplatelets (fGnPs) and functionalized MWCNTs (fMWCNTs), [ 16 ] and also mono‐filler and hybrid of carbon fibers (CFs) and MWCNTs. [ 17 ] They reported that the extent of phase separation of TPU soft and hard segments increased with the increase in MWCNTs concentration. [ 15 ] It was found that the nanocomposites containing both of fGnPs and fMWCNTs had a positive deviation from the law of mixtures in their mechanical, thermal and electrical properties.…”

“…[ 16 ] Their results also showed that, above the percolation threshold, the electrical conductivity of mono‐ and bi‐filler materials was improved by the application of shear. [ 17 ] In another work, Rostami et al [ 18 ] studied the influence of MWCNTs on the properties of PC/acrylonitrile butadiene styrene (ABS) blend. They reported that the electromagnetic interference shielding efficiency of the nanocomposites increased with the increase in the amounts of the nanofillers and the values were larger at higher frequencies.…”