Polymer compounding of graphene and related materials for advanced composite manufacturing

Lead Research Organisation: University of Cambridge
Department Name: Engineering

Abstract

Thermoplastic polymers and composites were perhaps one of the greatest material discoveries of the past century, while 3d printing is becoming the most significant manufacturing discovery of this century. Combined, they have enabled significant technological advancement in the capabilities of different products ranging from packaging to automotive to planes, and even space technology. The continued research and advancement of these technologies will impact nearly all areas of society in coming years. The most recent research into thermoplastic composites and 3d printing has come on the heels of the discovery of layered and 2-dimensional materials, such as graphene.
Graphene is single sheet of graphite, which is a single atom thick with carbon atoms arranged in a hexagonal lattice. It has garnered excitement in the research and industrial community due to its outstanding mechanical, electrical, thermal, and optical properties, among others. It's application in the field of composites has already enabled the fabrication of lighter, stronger, conductive materials, capable of replacing metals and currently used composites in many high-performance systems.
While graphene has shown its potential in these fields, research efforts are now aimed at moving these technologies from 'lab to fab'. This included not only the mass production of composite-ready graphene materials, but the techniques and industrial scale processes for their incorporation and integration into polymers and existing systems. This project will address each level of these considerations by investigating scale-up production techniques of graphene and layered materials and their thermoplastic composites with particular care for additive manufacturing techniques.
Considering these aims, this project is investigating the scale up of graphene production using environmentally friendly processes, such as the liquid phase exfoliation of graphene in water through the use of high-pressure homogenization. This technique provides large scale production of high-quality graphene for use in composites at the ton-scale per year. The resulting material is characterized by UV-Vis spectroscopy, Raman spectroscopy, atomic force microscopy, and scanning electron microscopy. Next, the produced materials are incorporated into polymers through several available processes, such as extrusion to produce pellets or 3d printing filaments, or through high shear incorporation in the high-pressure homogenizer with powdered polymers. The resulting composites are analysed using thermogravimetric analysis, differential scanning calorimetry, and laser flash analysis for the thermal properties, while tensile testing is used for mechanical characterization. The final step in moving these technologies to industry requires the demonstration of fabrication techniques. The composite materials are then compression molded, 3d printed, and injection molded, demonstrating the viable routes to industry for graphene-based materials from material synthesis to final device fabrication.

Planned Impact

Our vision is to take graphene from a state of raw potential to a point where it can revolutionise flexible, wearable and transparent (opto)electronics, with a manifold return in innovation and exploitation. Such change in the paradigm of device manufacturing may revolutionise the global industry. The importance of graphene was recognised by the 2011 statement of the Chancellor of the Exchequer launching the initiative that lead to the funding of the Cambridge Graphene Centre, where the proposed Graphene Technology CDT will be based. The aim is take graphene and related materials from "the British laboratory" to the "British factory floor". Not only does our vision align with this mandate, but it also exploits and strengthens several key areas of national importance where the UK has recognised excellence, such as printed electronics, energy and RF & Microwave Communications. Thus, we will strive for both economic impact, by stimulating new UK-manufactured high-value products, and societal benefits, by utilising graphene in potentially many areas including security, energy efficiency and quality of life.
The beneficiaries of our proposal will be of course the cohorts of students that will be trained every year, but will extend more widely. Considering the private sector, we have already indentified tens of companies that will benefit from our work. To achieve the final goal of graphene-technology, and to ease the transition to commercialisation, we have strong alignment with industry needs and engage them as project partners of the CDT: Dyson, Novalia, Plastic Logic, Nokia, Toshiba, BAE Systems, Aixtron, PEL, Nanocyl, IdTechEx, Philips, Dupont, CambridgeIP, Polyfect, Agilent, Nippon Kayaku, Victrex, IMEC. Many more are also partnering with the Cambridge Graphene Centre, and even more are expected to join and benefit directly or indirectly from our work. We consider the civilian sectors of healthcare, telecommunications, energy and homeland security to be those in which applications based on graphene can make significant impact on society at large. There are also applications in defence, especially in secure communications and radars. This will foster competitiveness and enhance quality of life. In particular, the proposed CDT will be of prime interest to industries dealing with the following devices and applications: 1. Mobile communications, wireless sensor networks, including wearable devices. 2. Nano-structured materials for light and microwave energy harvesting. 3. Active and reconfigurable microwave, terahertz and optical materials, including advanced antenna applications for radar and communications.
Policy-makers, within international, national, local government will also benefit. If the vision of graphene as the material of the 21st century is fulfilled, there will be a need for its properties, benefits, applications and advantageousness compared to current technology to be known by the relevant public bodies. For example, any new policy on energy saving, or mobile communications may need to include a reference to the benefits, or limitations, of graphene-based devices.
Economic resilience and innovation require post-doctoral researchers and students trained in new areas. We will contribute to increasing the talent pool for the future graphene industry. The proposed doctoral training centre will provide unique training to students in various aspects of graphene technology: from graphene nanotechnology to energy, RF/microwave and (opto)electronics. This will develop many skilled researchers over the project lifetime, who will stimulate the sustainability of UK graphene engineering research and future commercialisation opportunities across a variety of sectors.

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