Plastic Pollution Crisis and Recycling Rates
According to a WWF study, approximately 10 million metric tons of plastic is discharged in the oceans each year, this is equivalent of 23,000 Boeing 747 flights (Krauth, Schmidt, and Wagner, 2017). The European plan for recycling plastics and increasing the circular economy aims to address this waste build-up issue by highlighting the political and corporate discussion around sustainable industrial production growth (Geissdoerfer et al., 2017).
If recycling is profitable, people will do it. Recycling metal and glass in areas where money is exchanged for bottles and cans is a huge success. Sadly, the incentives for recycling plastic have weakened. Only 9% of plastic garbage is recycled as of 2015. Most of the waste is deposited in landfills or the natural world. However, new technologies have developed that enable consumers to recycle waste plastic effectively by 3D-printing it into useful items at a fraction of the regular cost. Toys and games, recreational goods, and other electronics are all being made from recycled plastic by people who have access to millions of free ideas. DRAM, or distributed recycling and additive manufacturing, is the name given to this technology (Geyer, 2017).
Plastics have a broad range of chemical and mechanical qualities that may be used in a number of applications. Plastic pollution is a huge problem because of its inability to degrade, which has serious consequences for the ecosystem (Ryberg et al., 2019). On the other hand, recycling rates in the plastic packaging industry remain low (about 14 percent) (Hahladakis and Iacovidou, 2018). Recycling rates are around 32.5 percent in Europe, which is considered to be a leader in environmental management (Plastics, 2019). There is a discrepancy between these figures and the overall volume of plastic garbage in circulation (Kranzinger et al., 2018). Policy and commercial discussions on sustainable industrial development are increasingly focusing on the European Strategy for Plastics throughout the Circular Economy (CE), which intends to limit waste building by utilising a circular economy approach to plastics (Geissdoerfer et al., 2017). CE discusses about a very important social issue: the current economic concept of “take, make, throw away,” or “linear economy,” and its negative effects, such as depletion of resources, waste, habitat destruction, pollutants (water, air, and soil), or a non-sustainable economic system (van Buren et al., 2016).
Additive Manufacturing (AM), which is also called 3D printing, could play a big role in moving from a linear to a circular economy, even though it isn’t as common as it was in the past. The ability of AM technologies to convert a computer model into the deposition of material (in the form of points, lines, or regions) for the construction of 3D components is expected to revolutionise manufacturing (Bourell et al., 2017).
The DRAM approach begins with plastic trash, which includes anything from discarded packaging to damaged goods.
Figure 1
The first thing to do is to separate and clean the plastic with soap and water, or even put it in the dishwasher. It is then necessary to grind the plastic to a fine powder. For small amounts, a shredder that cuts paper and CDs into small pieces will work well. Open-sourced blueprints for an industrial waste plastic granulator are accessible on the internet in greater quantities. Following that, there are a few options available to you. Using a recycle bot, a machine that grinds plastic into filament for low-cost 3D printing, you may transform the particles into a 3D printing filament. Comparing the price of 3D-printed recycled bot filament to the commercial filament (which costs around US$10 or more per pound), you can see that it is much cheaper. Making items at home from garbage is particularly more enticing now that the epidemic has disrupted global supply networks (Geyer, 2017).
Benefits of 3D Printing Technology in Plastic Recycling
The second method is more recent: Using fused particle manufacturing; you may 3D-print discarded plastic granules straight into finished objects, skipping the stage of producing filament. Large items printed on bigger printers, such as the commercial open source GigabotX printer, are the most suitable for this strategy; nevertheless, desktop printers may also benefit from it. Syringe printers may also print directly on granulated plastic debris; however, this is less common due to the syringe printer’s low print capacity (Hamel, 2022).
DRAM is supported by a broad range of open-source devices, including shredders, recycling bots, and fused filament or fused particles 3D printers made by my research group with others across the globe. It has been shown that these devices are capable of working with a wide range of materials, including PET water bottles. Plastic debris with a recycling emblem on it may now be turned into useful items. “Eco-printing” projects in Australia have also shown that DRAM may be used in remote areas with no recycling or electricity by employing solar-powered equipment.” DRAM may be used in any location where people are present, trash plastic is plentiful, and the Sun is shining, which is about everywhere (Hamel, 2022).
A century after they first entered into everyday lives, plastics still are vital materials with such a wide range of qualities and uses that people use at home, at work, and on the road. Plastics may be used in a wide variety of ways since they are exceedingly adaptable (Mikula et al., 2021). High mechanical strength, low density, lightweight, simple production, and cheap cost are the undeniable advantages of these materials (Mwanza and Mbohwa 2017). Plastics have been used in packaging, automobiles, power, building, and transportation, as well as in medical, agriculture and other industries because of these properties. Massive volumes of garbage are generated as a result of the widespread use of plastic, and this waste is difficult to manage. In 2018, 359 million metric tonnes of plastics were produced across the world (in the EU 61.8 million metric tons). Over the next 20 years, it is expected that this number will double. Plastic garbage is not properly handled in many nations, and as a result, it ends up in landfills. Plastic waste is piling up in landfills at an alarming rate, and there isn’t enough room for all of it. To achieve the criteria of the circular economy initiative, stricter waste management legislation is needed. So, using recycled plastics for 3d printing as an alternative is a great way to reduce waste and environmental damage (Mikula et al., 2021).
The aim of this research is to show that recycled plastic can be used for 3D printing.
The objectives of this research are:
- To check if plastic can be recycled.
- To check if there is enough plastic to be recycled.
- To check the feasibility of recycled plastic in 3D printing.
- To check if recycled plastic can be scaled in 3D printing to be used for commercial applications.
This topic has been prioritised by the European Commission, which aims to make all plastic packaging recyclable by 2030. (European Commision, 2015; European Commission, 2018). Various obstacles have been identified, including political (e.g. China’s decision to restrict the import of some types of plastic trash (Brooks et al. 2018)), economic (e.g. inadequate or non-existent marketplace for recyclable plastic (Milios, 2018)), social (e.g. cultural perspectives including attitudes regarding commodities recovered from waste (Blomsma, 2018) and technical (e.g. recycling designs) obstacles (Horvath et al., 2018). When it comes to extracting value from recycled plastics and materials, it is imperative to design a framework that improves both economics and quality. According to experts, the examination of material quality upstream and downstream of where wastes are deposited seems to be a more critical element that must be taken into account (Iacovidou et al., 2019).
Introduction to the Circular Economy Approach for Sustainable Industrial Production Growth
Plastic garbage is not properly handled in many nations, and as a result, ends up in landfills. Plastic waste is piling up in landfills at an alarming rate, and there isn’t enough room for all of it. To achieve the criteria of the circular economy initiative, stricter waste management legislation is needed. Only 24.9 percent of the plastic garbage generated in the EU was disposed of in landfills, despite 75.1 percent of the debris being processed. Re-extrusion, mechanical recycles, chemical reuse or thermal processes (combustion, pyrolysis, gasification) may all be used to deal with the ever-increasing volume of plastic trash (Al-Salem et al., 2009). Using primary recycling, it is possible to recover pure polymer leftovers with properties identical to those of the original raw material. A common method for extrusion residues, for example, maybe employed with this method (Singh et al., 2017). Secondary recycling involves the use of additional, potentially contaminated resources. The conversion process removes these contaminants, which were first eliminated during the shredding process. Granulated plastics are made from material that has been treated and reprocessed several times. In contrast, primary recycling frequently yields lower-quality material. Solubilization (solvolysis) is a method of depolymerizing polymers into chemicals that can be repurposed in the creation of new goods. The least ecologically friendly approach is to recover energy from polymeric materials, however, polymers have large energy content and a calorific value that is comparable to fuel oils (on average 42 MJ/kg) (Kumar et al., 2011). In order to avoid the production of various organic pollutants like dioxins, it is vital to monitor the emissions from these operations on an ongoing basis (Ragaert et al., 2017). Microorganisms are often unable to digest plastics because bacteria have not created enzymes that allow for the biological disintegration of this material. Polylactide (PLA) and polycaprolactone (PCL) are two examples of biodegradable polyesters that break down under the impact of the environment (Shah et al., 2008). These materials are utilised in the creation of 3D printing filaments.
Plastic pyrolysis or polymer under-degradability provides environmental risks that need processing. Using landfills is merely a short-term fix. A new solution is needed because of the constant manufacturing of plastics and the low degree of processing. Preventing waste from being generated is, of course, the ideal waste management method. There are several reasons why plastic packaging has become so prevalent and pervasive in the environment, including consumer lifestyles and convenience, advantages of features, and lower manufacturing costs than glass and metal packaging. When it comes to creating a waste-free economy, it’s only an idea. As a result, cost-effective plastic processing methods are urgently required. Waste polymer 3D printing is a novel, potentially game-changing option that has the greatest chance of success in the future (Mikula et al., 2021).
3D models are used to create products in an additive manufacturing method, which involves layering materials together to create the finished product from the original design (ASTM, 2015). Binder jetting, direct energy deposition, powder bed fusion, sheet lamination and vat photo-polymerization are the seven main types of processes that the ISO standard says are the seven main types of processes that are used. FIG. 2 shows the categorization of AM technologies that employ polymer materials, as well as a description of the physical principle that is used throughout the process (Sanchez et al., 2020).
Figure 2
The 3D printing industry is one of the fastest expanding industries in the world. It is predicted that the market would rise by more than 23% by 2021 when compared to 2016, reaching more than 10 billion USD. It has only been around for a few years, but 3D printing has grown quite popular in the past few years. Because of its simplicity and cheap cost, it is largely utilised in prototype and small-scale processes. A wide range of industries, including aerospace, defense, automotive, healthcare, or construction, have seen a considerable increase in the use of 3D printing (Shah et al., 2019).
Thermoplastic filaments are the most common kind of material used in 3D printing. Both ABS and PLA, a polylactic acid derivative, are among the most widely used. Finally, there is polycarbonate (PC), polystyrene (PS), polyetherimide (PEI), polyether ketone (PEK), and many different types of polyethylene. These include LDPE (low-density PE) and HDPE (high-density PE). A wide range of ordinary things may be printed using these materials: automobile components; medical equipment; prototypes; packaging; tiny garden architecture; toys; as well as many other items (Anderson, 2017).
Waste from unsuccessful prints and rejected support structures is a major problem with 3D printing despite its many benefits, Furthermore, the capacity to build components without the need for machining of tools results in a high proportion of prints being utilised as throwaway prototypes. As additive technology advances and the number of thermoplastic prints rise, a waste management issue arises. Plastic filaments that have been recycled may be a viable alternative. In the extrusion process, raw materials are fed into an extruder where they are changed into a homogenous substance in the shape of a line with preset parameters under the effect of heat. Many companies are now offering filaments that are manufactured from recycled PLA or ABS, which is becoming more popular. The mechanical characteristics of recycled filaments have not yet been thoroughly studied. They have a significant impact on the quality of printed materials. Recycled filaments may be used as a starting point for future research into 3D printing technology by comparing them to the virgin filament (Anderson, 2017).
In recent years, the worldwide production of plastic-based products has grown tremendously. According to the PEMRG (Plastics Europe Market Research Group), worldwide plastic output reached 359 million tonnes in 2019, with 51 percent of that production occurring in Asian nations and 17 percent occurring in European countries. The production of virgin plastics consumes around 4% of world oil production each year, or about 1,3 billion barrels (Singh et al., 2017b). A typical polymer is non-degradable and can remain in the environment for many centuries (Gu and Ozbakkaloglu, 2016). There is therefore a serious concern about waste created by this kind of garbage. Plastics might account for up to 90% of total consumption, based on current estimates. While recycling plastic waste is increasing, landfills now hold as much as 80% of all plastic waste. Plastics made from HDPE, LDPE, PP, and PVC, which are often used by manufacturers and disposed of in landfills to contribute to GHG emissions, are a major source of concern (Aboulkas et al., 2010). PLA-related waste, on the other hand, is a considerably lesser worldwide issue since its natural origins don’t have as big of an influence. Unfortunately, the mechanical durability of things manufactured of this material is lower than that of goods made of other materials, which discourages prospective producers from utilising them more often. The most significant issue associated with the reuse of the materials is the concern of the material’s qualities deteriorating after it has been recycled multiple times. Furthermore, a loss of stability is noted, which has the potential to negatively impact people’s health (Lithner et al., 2011).
Using 3D printing, it is now possible to build an intricate structure on a smaller scale than ever before. The development of new technologies also brings with it concerns linked with the production of more plastic. 3D printing waste isn’t a big problem right now, according to the research, but the technology itself can be used to reduce post-production waste (Cruz Sanchez et al., 2017). Plastic waste for 3D printing may be recycled by several methods such as grinding, remelting, and extrusion. Other activities include selective material separation, contamination or purification, decontamination or purification, and extrusion. The logistical and economic issues that arise as a consequence of this procedure are the most significant roadblocks. Material recycling has no economic benefits, according to the study, and the price of the filament used in the initial manufacturing process determines the cost of the recycled product (Hopewell et al., 2009). The growing number of environmental regulations and the recycling of plastic waste make this a viable choice despite the absence of evident economic benefits.
Polypropylene (PP), polyvinyl chloride (PVC), high- and low-density polyethylene (HDPE, LDPE), polystyrene (PS), polyethylene terephthalate (PET), and the “other” category, which mostly comprises of ABS and polycarbonate, are all recycled globally (PC). All of the above categories have been studied for the feasibility of 3D printing filament re-use, as described in the literature. The natural origin of PLA, on the other hand, has accounted for the vast majority of the study into the possibilities of employing polymers for 3D printing. In previous research (Anderson, 2017), the impact of repeated material recycling was investigated, as well as the potential of inserting an extra strengthening component into the mix (Zhao et al., 2018b). A broad waste recycling approach for 3D printing has been created and executed based on current research.
Figure 3
The first step is to separate and clean the material, and the second is to grind the plastic. Next, the ground material is heated up so that it can be pushed out of the mould at a high rate of speed (the temperature is set depending on the polymer type). In the meanwhile, the printer has been filled with the filament. The printed part is examined in great detail (mechanical, rheological, and structural properties). A second milling is performed on the material under investigation (Zenkiewicz et al., 2009). Add a binder (e.g. silicone oil) and another component to the mixed mixture before extruding it. Ground elements may also be dissolved in organic solvents with additional reinforcing components, then evaporated and extruded.
It is in accordance with circular economy principles that plastic is processed and 3D printer filaments are produced. This has a huge impact on the environment since it helps to reduce anthropogenic contamination with plastics. As a result, a large number of educational programmes aiming at arranging participatory events and disseminating information regarding plastic recycling are being planned. It is the goal of the Perpetual Plastic Project to increase public awareness of the usefulness and worth of plastics. The organisers demonstrate how 3D printing technology may be used to transform plastic waste into new and valuable goods in front of the festival attendees. Plastic trash is washed and dried, then ground up and spun into filament before being printed in three dimensions. It takes around 30 minutes to complete the process. Green printing is a key component of the Reflow project’s tagline: “Go green, print like a dream.” It is the goal of the project to convert PET bottles into an environmentally friendly rPET filament for 3D printing. The organizers hope to raise awareness about the need of processing beverage bottles because the industry currently recycles just 5% of all plastic generated. As of 2050, plastic will outnumber fish in the world’s waters, resulting in the demise of the marine ecology. The Coca-Cola® Company, the world’s largest producer of PET bottles, has also been actively engaged in the battle against plastic pollution. The EKOCYCLE Cube 3D Printer Project’s goal is to recycle plastic waste via the use of technology, design, and style, as well as to effect change across society (Pakkanen et al., 2017).
Excessive garbage is prevented from entering the environment by implementing a circular economy for plastic, and specifically for PET. Because of the effort, rPET is being created, which has qualities that are similar to those of traditional non-recycling PET. Nefilatek is a Canadian firm that aims to generate a high-performance polymer (HIPS) and polycarbonate (PC) filament from 100 percent recycled plastic. Current research and development efforts are focused on preparing the firm for the commercialization of its goods, which will take place soon. Additionally, worldwide communities are being developed, bringing together those who are attempting to find a solution to the issue of plastic pollution (i.e., Precious Plastic, Plastic Bank). Recycling is something that Precious Plastic is dedicated to promoting and teaching. To spread the word about recycling techniques, they demonstrate how to use machineries like shredders, extruders and sheet presses as well as things like furniture, jewellery, interior design components and even building materials. They also educate people on how to make money from recycling, and they have a bazaar where people can sell their recycled goods. It is generally agreed that the Plastic Bank is the most well-known and well-recognized effort to reduce the quantity of plastic waste dumped into the oceans (Pakkanen et al., 2017).
Nearly half a billion 0.5-litre bottles, 1.5 billion coffee cup lids, and more than 500 billion plastic straws have been collected and recycled since the organization’s establishment in 2013. A total of 4300 collectors from Haiti, the Philippines, and Indonesia are taking part in the operation. Recycle Rebuilt is a non-profit organisation dedicated to converting garbage into opportunities. In order for plastic garbage to be transformed into usable products, it is essential to understand how to recycle and to use relevant technologies and machinery to do this. As part of its responsibilities, it also provides materials and trains volunteers on how to manage recycling equipment. Overcrowding in landfills is a major concern on the island of Dominica, which was devastated by a storm in 2017 and now faces a serious danger to human health and ecological safety as a result of the Recycle Rebuilt initiative. The group established a facility for the collection, sorting, and processing of plastic waste into common commodities, which is already operational (Pakkanen et al., 2017).
While this study will be focused on the analytical elements, it will also include genuine evidence on recyclable polymers and their influence on 3D printing, including the types of literature, diverse statistics, and other relevant information. For exactly these reasons, the qualitative foundation of this dissertation has been established. Furthermore, from an interpretivist perspective, this is a subjective matter. As a result of the substantial qualitative research undertaken in this study, a full understanding of the subject matter would be gained, although one that is linguistic in character. Primary research would not be included in the discussion since it would entail analysing current actions and laws, which cannot be performed using interview and survey methods.
The existing literature, which has been published by a large number of academics, will serve as the basis for our investigation. In order to answer the research questions and help the study reach its objectives, it is essential to conduct a thorough evaluation of the literature. The use of a wide body of literature in a thematically grounded method allows the researcher to conduct a comparative study and assess whether or not the research hypotheses are valid.
This research is aimed at establishing that the problem of plastic can be resolved through recycling it and using it for 3D printing. This is a cost-effective manner of resolving a problem by making use of plastic, for another thing, so as to act as a material for different use. The expected outcome is to establish that the recycling of plastics is a good opportunity for being used in 3D printing.
Aboulkas, A. and El Bouadili, A., 2010. Thermal degradation behaviours of polyethylene and polypropylene. Part I: Pyrolysis kinetics and mechanisms. Energy Conversion and Management, 51(7), pp.1363-1369.
Al-Salem, S.M., Lettieri, P. and Baeyens, J., 2009. Recycling and recovery routes of plastic solid waste (PSW): A review. Waste management, 29(10), pp.2625-2643.
Anderson, I., 2017. Mechanical properties of specimens 3D printed with virgin and recycled polylactic acid. 3D Printing and Additive Manufacturing, 4(2), pp.110-115.
Blomsma, F., 2018. Collective ‘action recipes’ in a circular economy–On waste and resource management frameworks and their role in collective change. Journal of Cleaner Production, 199, pp.969-982.
Bourell, D., Kruth, J.P., Leu, M., Levy, G., Rosen, D., Beese, A.M. and Clare, A., 2017. Materials for additive manufacturing. CIRP annals, 66(2), pp.659-681.
Brooks, A.L., Wang, S. and Jambeck, J.R., 2018. The Chinese import ban and its impact on global plastic waste trade. Science advances, 4(6), p.eaat0131.
Cruz Sanchez, F.A., Boudaoud, H., Hoppe, S. and Camargo, M., 2017. Polymer recycling in an open-source additive manufacturing context: mechanical issues. Addit Manuf 17: 87–105.
Europe, P., 2016. Plastics—The Facts 2016. An analysis of European latest plastics production, demand and waste data.
European Commission, A., 2018. A European strategy for plastics in a circular economy. Communication from the Commission to the European Parliament.
Geissdoerfer, M., Savaget, P., Bocken, N.M. and Hultink, E.J., 2017. The Circular Economy–A new sustainability paradigm?. Journal of cleaner production, 143, pp.757-768.
Geyer, R., 2017. Production, use, and fate of all plastics ever made. [online] Available at: <https://www.science.org/doi/10.1126/sciadv.1700782> [Accessed 9 April 2022].
Gu, L. and Ozbakkaloglu, T., 2016. Use of recycled plastics in concrete: A critical review. Waste Management, 51, pp.19-42.
Hahladakis, J.N. and Iacovidou, E., 2018. Closing the loop on plastic packaging materials: What is quality and how does it affect their circularity?. Science of the total environment, 630, pp.1394-1400.
Hamel, M., 2022. Gigabot X Update – re:3D | Life-Sized Affordable 3D Printing. [online] Re3d.org. Available at: <https://re3d.org/gigabotx-update/> [Accessed 9 April 2022].
Hopewell, J., Dvorak, R. and Kosior, E., 2009. Plastics recycling: challenges and opportunities. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1526), pp.2115-2126.
Horvath, B., Mallinguh, E. and Fogarassy, C., 2018. Designing business solutions for plastic waste management to enhance circular transitions in Kenya. Sustainability, 10(5), p.1664.
Iacovidou, E., Velenturf, A.P. and Purnell, P., 2019. Quality of resources: a typology for supporting transitions towards resource efficiency using the single-use plastic bottle as an example. Science of the total environment, 647, pp.441-448.
Kranzinger, L., Pomberger, R., Schwabl, D., Flachberger, H., Bauer, M., Lehner, M. and Hofer, W., 2018. Output-oriented analysis of the wet mechanical processing of polyolefin-rich waste for feedstock recycling. Waste Management & Research, 36(5), pp.445-453.
Krauth, T., Schmidt, C. and Wagner, S., 2017. Export of Plastic Debris by Rivers into the Sea. Environmental Science and Technology.
Kumar, S., Panda, A.K. and Singh, R.K., 2011. A review on tertiary recycling of high-density polyethylene to fuel. Resources, Conservation and Recycling, 55(11), pp.893-910.
Lithner, D., Larsson, Å. and Dave, G., 2011. Environmental and health hazard ranking and assessment of plastic polymers based on chemical composition. Science of the total environment, 409(18), pp.3309-3324.
Mikula, K., Skrzypczak, D., Izydorczyk, G., Warcho?, J., Moustakas, K., Chojnacka, K. and Witek-Krowiak, A., 2021. 3D printing filament as a second life of waste plastics—A review. Environmental Science and Pollution Research, 28(10), pp.12321-12333.
Milios, L., 2018. Advancing to a Circular Economy: three essential ingredients for a comprehensive policy mix. Sustainability Science, 13(3), pp.861-878.
Mwanza, B.G. and Mbohwa, C., 2017. Drivers to sustainable plastic solid waste recycling: a review. Procedia Manufacturing, 8, pp.649-656.
Pakkanen, J., Manfredi, D., Minetola, P. and Iuliano, L., 2017, April. About the use of recycled or biodegradable filaments for sustainability of 3D printing. In International conference on sustainable design and manufacturing (pp. 776-785). Springer, Cham.
Ragaert, K., Delva, L. and Van Geem, K., 2017. Mechanical and chemical recycling of solid plastic waste. Waste management, 69, pp.24-58.
Ryberg, M.W., Hauschild, M.Z., Wang, F., Averous-Monnery, S. and Laurent, A., 2019. Global environmental losses of plastics across their value chains. Resources, Conservation and Recycling, 151, p.104459.
Sanchez, F.A.C., Boudaoud, H., Camargo, M. and Pearce, J.M., 2020. Plastic recycling in additive manufacturing: A systematic literature review and opportunities for the circular economy. Journal of Cleaner Production, 264, p.121602.
Shah, A.A., Hasan, F., Hameed, A. and Ahmed, S., 2008. Biological degradation of plastics: a comprehensive review. Biotechnology advances, 26(3), pp.246-265.
Singh, N., Hui, D., Singh, R., Ahuja, I.P.S., Feo, L. and Fraternali, F., 2017. Recycling of plastic solid waste: A state of art review and future applications. Composites Part B: Engineering, 115, pp.409-422.
Singh, N., Hui, D., Singh, R., Ahuja, I.P.S., Feo, L. and Fraternali, F., 2017. Recycling of plastic solid waste: A state of art review and future applications. Composites Part B: Engineering, 115, pp.409-422.
Van Buren, N., Demmers, M., Van der Heijden, R. and Witlox, F., 2016. Towards a circular economy: The role of Dutch logistics industries and governments. Sustainability, 8(7), p.647.
?enkiewicz, M., Richert, J., Rytlewski, P., Moraczewski, K., Stepczy?ska, M. and Karasiewicz, T., 2009. Characterisation of multi-extruded poly (lactic acid). Polymer Testing, 28(4), pp.412-418.
Zhao, X.G., Hwang, K.J., Lee, D., Kim, T. and Kim, N., 2018. Enhanced mechanical properties of self-polymerized polydopamine-coated recycled PLA filament used in 3D printing. Applied Surface Science, 441, pp.381-387.
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