Nanotubes Ternary Composites Research Articles

Enhanced thermoelectric properties of polyaniline/polypyrrole/carbon nanotube ternary composites by treatment with a secondary dopant using ferric chloride

Polymer/carbon nanotube (CNT) composites have lower electrical conductivity than pristine CNTs since the carrier barriers at the interface between the polymer and CNTs hinder the carrier pathways from tube to tube.

Synergy of Photocatalysis and Adsorption for Simultaneous Removal of Hexavalent Chromium and Methylene Blue by g-C3N4/BiFeO3/Carbon Nanotubes Ternary Composites

A novel graphite-phase carbon nitride (g-C3N4)/bismuth ferrite (BiFeO3)/carbon nanotubes (CNTs) ternary magnetic composite (CNBT) was prepared by a hydrothermal synthesis. Using this material, Cr(VI) and methylene blue (MB) were removed from wastewater through synergistic adsorption and photocatalysis. The effects of pH, time, and pollutant concentration on the photocatalytic performance of CNBT, as well as possible interactions between Cr(VI) and MB species were analyzed. The obtained results showed that CNTs could effectively reduce the recombination rate of electron-hole pairs during the photocatalytic reaction of the g-C3N4/BiFeO3 composite, thereby improving its photocatalytic performance, while the presence of MB increased the reduction rate of Cr(VI). After 5 h of the simultaneous adsorption and photocatalysis by CNBT, the removal rates of Cr(VI) and MB were 93% and 98%, respectively. This study provides a new theoretical basis and technical guidance for the combined application of photocatalysis and adsorption in the treatment of wastewaters containing mixed pollutants.

SPS/PPS/Carbon Nanotube Ternary Composites with Improved Conductivity by Controlled Melt Blending Process

ABSTRACTSyndiotactic polystyrene/poly(phenylene sulfide)/carbon nanotube ternary nanocomposites were prepared using a controlled melt blending process. The composites exhibited sea–island structures of syndiotactic polystyrene as continuous phase and poly(phenylene sulfide) as dispersed phase, and carbon nanotubes were concentrated on the interface or in the syndiotactic polystyrene phase. As a result, the theoretical percolation threshold of the composite was reduced to 0.399 wt%. Moreover, the electrical conductivity of the composite remained stable even after being processed for several times. Results revealed a particular effect of carbon nanotubes that their presence can enhance the dispersion of phases and provide conductivity to the blend at low contents in this system.

Largely improved thermal conductivity of HDPE/expanded graphite/carbon nanotubes ternary composites via filler network-network synergy

Utilizing the synergistic effect of various fillers is an efficient strategy to enhance the thermal conductivity of polymer composites, in which the key is to modulate their dispersion and network formation in polymer matrix. In this work, expanded graphite (EG) was individually added into high density polyethylene (HDPE) to fabricate first the binary composites through melt blending. The electrical conductivity of the prepared composites was measured to determine the percolation threshold for HDPE/EG composites. Then HDPE/EG composites with three compositions, representing below percolation, just percolation and above percolation, respectively, were chosen as matrix and melt mixed with carbon nanotubes (CNTs) to make HDPE/EG/CNTs ternary composites. It was found that adding CNTs results in a linear increase of thermal conductivity for HDPE/EG composites with composition below percolation, along the line by adding the same amount of EG. While a jump of thermal conductivity was observed by adding CNTs for HDPE/EG composites with composition just and above percolation. The electrical conductivity and rheology property were measured and SEM experiment was carried out to explore the filler dispersion and their network formation in HDPE matrix. All the results suggested a possible location CNTs in EG filler network for HDPE/EG composites with composition just and above percolation. Thus the formation of CNTs network within EG network is attributed to the main reason for the largely enhanced thermal property. This work endows a new enlightenment to fabricate the composites with a great thermal conductivity.

Poly(3,4-ethylenedioxythiophene)/graphene/carbon nanotube ternary composites with improved thermoelectric performance

Polymer based ternary thermoelectric composites have been studied. Here, poly(3,4-ethylenedioxythiophene)/graphene/carbon nanotube (PEDOT/graphene/CNT) ternary composites are prepared by in situ polymerization and subsequent physical mixing. Then, the morphology is directly observed by scanning electron microscopy. Finally, the thermoelectric performances are measured and discussed, where the effect of acid-treatment is investigated and comparison with those of the neat PEDOT and the binary PEDOT/graphene composite is conducted.

Largely enhanced thermal and electrical conductivity via constructing double percolated filler network in polypropylene/expanded graphite – Multi-wall carbon nanotubes ternary composites

In this study, we report a sharp increase of both thermal and electrical conductivity in polypropylene (PP) via formation of double percolated filler network with dense small-sized multi-wall carbon nanotubes (MWCNT) network located within loosened large-sized expanded graphite (EG) network. The electrical conductivity of PP/EG composites which levels off after the percolation threshold can be further enhanced by adding MWCNT and is increased two orders of magnitude as the content of MWCNT reaches to its threshold. Besides, the thermal conductivity of PP/EG-MWCNT increases by 38.5% compared to PP/EG and is much higher than PP/MWCNT. Furthermore, an excellent electromagnetic interference shielding effectiveness of ∼60 dB is obtained at the sample thickness of only 1.3 mm. Then, effective medium theory model is applied to analyze the mechanism for the largely enhanced thermal and electrical conductivity. It is suggested that formation of double percolated filler network, in which three types of connections exist between EG and EG, EG and MWCNT as well as MWCNT and MWCNT, could effectively reduce the interface thermal resistance. Our work is important and provides some new idea for the preparation of polymer composites with excellent thermal and electrical conductivity via constructing double percolated filler network.

Enhancement of Carbon Nanotube Particle Distribution in PPS/PEEK/Carbon Nanotube Ternary Composites with Sausage-Like Structure.

Carbon nanomaterial particles were selectively distributed in an incompatible and high-melting-temperature polymer blend interface, or in a particular phase, to obtain conductive composites. The composite products revealed poor morphology stability and mechanical performance due to processing several times. Poly(phenylene sulfide) (PPS) and poly(ether ether ketone) (PEEK) polymers with large differences of processing temperatures were selected as blend components to obtain a compatible blend. PPS/PEEK/multi-walled carbon nanotube (MWCNT) ternary nanocomposites were prepared using a controlled melt blending process. The composite samples with similar sausage-like structures of PEEK, as a dispersed phase, promote MWCNT to maximize concentration distribution in the PPS continuous phase. As a result, the theoretical percolation threshold of the composite reduced to 0.347 wt %. Moreover, the conductivity of the composite remained stable even after processing several times. CNTs revealed a particular effect when distributed selectively in this kind of system: it can enhance the dispersion of phases and also provide conductivity to the blend at small CNT contents, which can provide more useful ideas for the development of high-melting-temperature and antistatic or conductive plastic materials.

Coherent polyaniline/graphene oxides/multi-walled carbon nanotubes ternary composites for asymmetric supercapacitors

A coherent polyaniline (PANI)/graphene oxides (GOs)/multi-walled carbon nanotubes (MWCNTs) composite was prepared by in-situ solution polymerization as a positive electrode of supercapacitors. The orderly growth of PANI nano-dots on GOs led to the formation of the nano-ravines that can enhance ions diffusion efficiency. MWCNTs surrounded by PANI connected all components, and thus the conductivity with the increasing electron transfer rate was improved. The results showed that the electrode exhibited the outstanding electrochemical performances with the specific capacitance up to 696Fg−1 at 20mVs−1. The KOH-activated GOs/MWCNTs were used as a negative electrode to assemble an asymmetric supercapacitor (ASC). The ASC possessed an extended working potential (1.6V), a good rate capability (58% capacitance retention even after the current density being increased by 10 times), an excellent cycling stability (89% capacitance retention after 3000 cycles), and a decent average energy and power density (69Wh/kg and 6.4kW/kg).