ARC Green Manufacturing Research Hub

Working with TES-AMM, a leading e-waste recycler, Hub researchers were able to transform waste plastics from electronic waste (e-waste) into the first sustainable plastics filament for 3D printers, using thermal transformative techniques and other innovations. The research for this has helped the UNSW SMaRT Centre develop the building blocks for its breakthrough MIcrofactorie® technologies and to continue to advance its microrecycling science. Relevant industry partners originally joined the Hub to find a solution for toner cartridges, rich in iron and carbon, and while aspects of that research proved fruitful, lab testing showed a new green filament made from 100% plastic displayed outstanding physical properties and potential. See the Filaments section on the MICROfactorie^TM technologies webpage for more details.

After developing novel surface modification technology for improving the wear and corrosion resistance of high carbon steel, Hub researchers worked with industry partner MolyCop and initiated a pilot scale plant trial at MolyCop's Newcastle steelworks site. This pilot scale trial helped to understand limitations of implementing the process in industrial scale settings. After number of rounds of modification, the process was optimised and the production of grinding media using the novel modified surface commenced, using onsite waste at MolyCop. Lab analysis of samples found that this new process improved the abrasion resistance of these steels by 30% and corrosion resistance by 50%. These samples then were subjected to an industrial scale ball-mill to identify the grinding media performance. Not only was new science and technology developed for this grinding media application, but the process to implemented this novel process in industrial setting and produce these new grinding media products was commenced. See the Surface Modification section on the Technologies and Products webpage for details about further developments of this sort of technology.

In this project, in partnership with Nespresso, Hub researchers used their the novel Thermal Disengagement Technology (TDT) to recycle the polymer laminated aluminium packaging (PLAP) of coffee pods to recover the valuable aluminium that had been 'contaminated' with coffee. This new technique was applied to waste coffee capsules in lab trials which produced high-quality aluminium, unlike traditional recycling methods that can't separate the aluminium from the waste coffee. Oxidation of the recovered aluminium was controlled and detected less than 1% through this new and innovative process. Through the TDT process, researchers demonstrated this recovered, clean aluminium has the desired scalability required for taking laboratory batch reactions towards industrial production. The level of purity of recovered aluminium is achieved at 96-99%, with only minor impurity/alloying for residual elements such as carbon, silicon and iron. See the TDT section on the Technologies and Products webpage for more details.

In this project, the Hub successfully investigated using biowaste mass and various plastics as a replacement for coke and coal in electric arc furnaces (EAF) for steel making. Different types of hardwood waste as well as plastic wastes including ABS (commonly used for children's play blocks, safety helmets, cars, and in electronic and many household goods), as well as printer toner and developer kit were used as alternative sources of carbon and iron sources, after studying their thermal, chemical and physical properties. Waste polymeric materials (plastic) consist mainly of carbon and hydrogen, elements vital in steel making due to their role as reductants. The industrial waste EAF slag was mixed with plastic and toner and their reduction behaviors were compared with coke. Our results showed that, using waste plastic and toner, iron oxide from EAF slag was completely reduced to the metallic iron in less than 5 minutes which is much shorter than coke. Partners TES and MolyCop helped with industrial scale trials. See the Green Steel^TM page for more details for information about earlier work in this area.

Hub researchers were able to use waste glass to make foams that are porous ceramics with an inorganic chemical structure that exhibit unique properties including fire resistance, sound and shock wave absorption. There is strong potential for a new product for the build environment making foam in this way. The foam was chemically inert in comparison to the organic insulation materials such as expanded polystyrene and polyurethane that suffer from short lifespan and combustibility. The team successfully produced glass foam ceramics from different types of waste glass including from e-waste and food waste. Excellent physical (strength) properties were recorded for the foamed ceramics, and the thermal insulation properties were very promising.

Working with various industry partners, Hub researchers were able to use a variety of waste materials to produce a range of 'green' materials and products for the built environment. This included recovering textile from end-of-the-life mattresses, and using waste wood and even plastic, to produce a new generation of high performance non-toxic engineered wood-plastic bio-composites, for use as tiles or panels, in buildings, furniture and architectural applications This multi-faceted research proved a new range of ‘made from waste’ building materials that could be produced in lab settings held industrial promise. The range of various waste materials used included waste wood, plastic, shells and seaweed, and a variety of textiles. This multi-faceted research spawned new collaborations with the SMaRT Centre and industry partners, leading to industrial testing and new technologies and products. See the other panels and Green Ceramics section on the MICROfactorie^TM technologies webpage for more details.

Hub researchers used 100% waste textiles to produce flat panels with acoustic qualities for use in the built environment. This research targets the recovery of assorted end-of-life textiles with the emphasis on promoting multi-stage cascading use of mixed fibre bulk, as a low-carbon alternative feedstock, for the advancement of Textile Fibre Reinforced Composite (TFRC) materials, for building applications. The noise absorption properties of the TFRCs is the focus of the study, since urban noise is considered by the World Health Organization amongst the major sources of anthropogenic environmental pollution of global industrialized urban settlements. The acoustic characterisation of the TFRCs is reported through the arithmetical mean values for the sound absorption coefficients (noise reduction coefficient, NRC), as function of the density, pore size, particle size, and thickness. See the Other panels section on the MICROfactorie^TM technologies webpage for more details.

This initiative focused on two projects.

1. Direct transformation of waste children’s toys to high quality products
using 3D printing

Due to the limitations that impede traditional recycling technologies, only a small percentage of waste plastic are currently recycled. Most recycling processes create products that are poor in terms of performance and value.

To produce high-quality products from plastic waste, thus bringing back these valuable materials into the economy after their end-of-life, it is important to know the change in polymer properties during cyclic reprocessing. During this project, investigations were conducted to create a profound understanding of the effects of cyclic reprocessing on the properties of nylon.

First, the flow behaviour of molten nylon in injection mould was studied. Then, optimised processing conditions were established by investigating the tensile and impact strength of moulded products. Finally, the influence of cyclic reprocessing on the material was assessed through tensile test, impact test, thermal analysis, X-ray diffractometry (XRD) and Fourier transform infrared (FTIR) spectroscopy.

The results indicate that nylon can be recycled at least four times without drastically changing its properties. A slight decrease in the tensile strength, impact strength, glass transition temperature and percentage crystallinity were observed as the number of reprocessing cycles increases. Together, the various elements of this research could be helpful in developing more effective and efficient recycling processes for plastic waste. 

Research paper

Nur-A-Tomal, Md. S., Pahlevani, F., Sahajwalla, V., 2020, Direct transformation of waste children's toys to high quality products using 3D printing: a waste‐to‐wealth and sustainable approach, Journal of Cleaner Production, 267, 122188. doi: 10.1016/j.jclepro.2020.122188

2. Sustainable solution to waste fishing net pollution

Waste polymeric fishing nets create wide-ranging issues for the environment and marine ecosystems. These nets are one of the biggest sources of water pollution, and are deadly for marine life, leading to suffocation. To mitigate these issues, it is crucial to introduce an economically viable process for reforming these waste nets and bringing them back into the economy as a value-added material, thus facilitating its collection and recycling.

The project demonstrated an economically viable process for recycling waste fishing nets into high quality plastic products while maintaining the material's original properties and colour. In addition to re-introducing this valuable material to the economy, the project quantified the reduction in CO2 emissions through this process. Our unique process has the potential to reduce environmental pollution as well as to produce valuable commercial products from 100% waste fishing net which will enable us to use waste as input in manufacturing processes.

Plastic fibres such as nylon and high-density polyethylene (HDPE), which is the cheaper option compared to nylon, are being commonly used for making fishing net instead of natural fibres owing to their excellent properties. After the use of fishing nets for several years, these nets are no longer suitable for fishing and are therefore deemed as waste. This project demonstrates it is viable to harness these waste materials so they can become valuable materials again.

Research paper

Nur-A-Tomal, Md. S., Pahlevani, F., Handoko, W., Cholake, S.T., Sahajwalla, V., 2020, Effect of cyclic reprocessing on nylon 12 under injection moulding: working towards more efficient recycling of plastic waste, Materials Today Sustainability