On the Use of Carbon Cables from Plastic Solvent Combinations of Polystyrene and Toluene in Carbon Nanotube Synthesis.

Alvin Orbaek White,Gemma Swan,Yubiao Niu,Léo Pointeaux,Andrew O Anderson,Ali Hedayati,Stuart J Corr,Varun Shenoy Gangoli,Richard E Palmer,Matthew Lloyd Davies,Jainaba Sallah-Conteh,Ioannis Tsampanakis,Sean Lethbridge,Tim Yick,Abigail Crane,Rhys Charles

doi:10.3390/nano12010009

Abstract

For every three people on the planet, there are approximately two Tonnes (Te) of plastic waste. We show that carbon recovery from polystyrene (PS) plastic is enhanced by the coaddition of solvents to grow carbon nanotubes (CNTs) by liquid injection chemical vapour deposition. Polystyrene was loaded up to 4 wt% in toluene and heated to 780 °C in the presence of a ferrocene catalyst and a hydrogen/argon carrier gas at a 1:19 ratio. High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Raman spectroscopy were used to identify multiwalled carbon nanotubes (MWCNTs). The PS addition in the range from 0 to 4 wt% showed improved quality and CNT homogeneity; Raman “Graphitic/Defective” (G/D) values increased from 1.9 to 2.3; mean CNT diameters increased from 43.0 to 49.2 nm; and maximum CNT yield increased from 11.37% to 14.31%. Since both the CNT diameters and the percentage yield increased following the addition of polystyrene, we conclude that carbon from PS contributes to the carbon within the MWCNTs. The electrical contact resistance of acid-washed Bucky papers produced from each loading ranged from 2.2 to 4.4 Ohm, with no direct correlation to PS loading. Due to this narrow range, materials with different loadings were mixed to create the six wires of an Ethernet cable and tested using iPerf3; the cable achieved up- and down- link speeds of ~99.5 Mbps, i.e., comparable to Cu wire with the same dimensions (~99.5 Mbps). The lifecycle assessment (LCA) of CNT wire production was compared to copper wire production for a use case in a Boeing 747-400 over the lifespan of the aircraft. Due to their lightweight nature, the CNT wires decreased the CO2 footprint by 21 kTonnes (kTe) over the aircraft’s lifespan.

Highlights

IntroductionCan the related production method from that carbon source contribute to the goal of achieving a positive climate output?
If carbon nanotubes (CNTs) are to be used for their lightweight and electrical conduction properties on a large/global scale [1], is there a scenario that justifies their use, especially given the large embodied energy requirements for their manufacture?in the age of sudden climatic shifts linked to carbon emissions, where would the carbon come from that would be used to make these CNTs? can the related production method from that carbon source contribute to the goal of achieving a positive climate output? To address these questions, we suggest that both plastics and solvents be used as carbon sources for CNT manufacture, and that they can create a positive environmental impact over the lifespan of their application in the aerospace sector
Using high resolution transmission electron microscopy, we observed the presence of both carbon nanotubes and residual metal catalyst particles (Figure 1)

Summary

Introduction

Can the related production method from that carbon source contribute to the goal of achieving a positive climate output? One of the key attributes of CNTs is being lightweight with a density that is 1/6th that of copper. This mass decrease will result in fuel savings for the automotive and aviation sectors. Plastic products synthesised from recycled plastics are often of inferior quality compared to freshly manufactured plastics, and are not feasible for the same applications. This results in fresh plastics having a wider range of uses, and holding greater economic value. Mixed plastics and/or composite plastic products are challenging or impossible to recycle unless separated

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