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issue 02/2021

  • Text
  • Balance
  • Moulding
  • Carbon
  • Recycling
  • Plastics
  • Sustainable
  • Products
  • Renewable
  • Biobased
  • Packaging
  • Materials
  • Bioplastics
Highlights: Injection Moulding Basics: Mass Balance

Material News New

Material News New findings about PHB making Cyanobacteria Polyhydroxybutyrate (PHB) is an interesting bioplastic for a wide variety of applications including those where degradability is an added value. One way to produce PHB naturally is by using cyanobacteria of the genus Synechocystis. However, the amount produced by these bacteria is usually very small. Researchers from the University of Tübingen (Germany) succeeded in identifying a control system in the bacteria that limit the intracellular flow of fixed carbon towards PHB. After removing the corresponding regulator and implementing several further genetic changes, the amount of PHB produced by the bacteria increased enormously and eventually accounted for more than 80 % of the cell's total mass. “We have created veritable plastic bacteria,” says Moritz Koch, first author of the study published in Microbial Cell Factories. See more comprehensive articles in recent issues of bioplastics MAGAZINE. Cyanobacteria, also known as microalgae or bluegreen algae, are among the most inconspicuous yet powerful players on our planet. It was blue-green algae that created our atmosphere and the ozone layer protecting us from UV radiation through photosynthesis about 2.3 billion years ago. “Cyanobacteria are, in a sense, the hidden champions of our planet,” Koch emphasizes. “This underscores the enormous potential of these organisms.” Since the blue-green bacteria only need water, CO 2 and sunlight, the researchers believe they are ideal candidates for climate-friendly and sustainable production. “Once this is established in the industry, the entire production of plastics could be revolutionized,” Koch says. The longterm goal, he says, is to optimize the use of the bacteria and to increase it to the point where large-scale use becomes possible AT New variants show increased PHB production (Photo: Moritz Koch / Universität Tübingen) Publications: Orthwein, T.; Scholl, J.; Spät, P.; Lucius S., Koch, M.; Macek,B.; Hagemann, M.; Forchhammer, K.: The novel PII-interactor PirC identifies phosphoglycerate mutase as key control point of carbon storage metabolism in cyanobacteria. PNAS February 9, 2021 118 (6) e2019988118; Koch M., Bruckmoser J., Scholl J., Hauf W., Rieger B., Forchhammer K. Maximizing PHB content in Synechocystis sp. PCC 6803: a new metabolic engineering strategy based on the regulator PirC. Microb Cell Fact 19, 231 (2020). Cellulose for electrical insulation Cellulose is a popular insulation material in electrical power transformers because it is clean and capable of resisting high temperatures, and it remains firm in oil used in transformers for both insulation and cooling purposes. However, the raw material must be packaged into the moulds manually, and a variety of different moulds are required. The process also consumes energy and produces plenty of waste. With the current methods, the value of production is approximately 1 billion euro a year. The EU-funded NOVUM project started in October 2017, with a planned run time of 4.5 years, develops automated methods for the production of cellulose-based electrical insulation components and for other applications such as the automotive industry and cruise ships. The international research group has managed to limit the manufacturing methods to the most promising ones: 3D printing and foam forming. 3D printing offers efficiency as well as new freedom in design. Foam forming, on the other hand, makes it possible to save energy in the manufacturing process. “Our goal is to build an automated production line in the premises of Brinter, Novum’s project partner in Finland (Turku), and test it in the relevant environment next autumn. In addition to efficiency, our goal is to save energy and material. Alongside the manufacturing methods, we are developing cellulose-based raw materials to suit the selected methods and applications the best possible way,” says Heli Kangas, Technology Manager from VTT (Espoo, Finland). As the research group works on developing cellulosebased materials and the manufacturing methods, it also investigates which other applications could be potential for the combination, in addition to transformers. A good starting point for the applications is the need to produce individual products or small series easily or to replace plastic parts with renewable material. The automatic production line built in the project will be tested and validated with electrical insulation components and parts used in car and cruise ship interiors. In addition to coordination work, VTT’s main focus in the project lies in material development. In order for cellulose to be 3D printable, it must be made thermoplastic, that is, pliable at an elevated temperature. Thermoplastic cellulose-based materials similar to oil-based plastics have previously been developed at VTT. However, for Novum project applications, it is important that the cellulosebased material also contains pure cellulose as much as possible as this is essential for insulation purposes. On top of modifying the material to ensure compatibility with the manufacturing process, the material’s properties, such as its strength and heat resistance, are also adjusted in accordance with the application requirements. Irrespective of the exact composition of the material, it is already clear that the pieces produced can be ground and reused as raw material on the same production line as many as eight times. AT | 42 bioplastics MAGAZINE [02/21] Vol. 16

Line expansion for food-grade plant-based polymer additives Palsgaard, the Danish pioneer in food emulsifiers from Juelsminde, has opened a new 10,000 tonnes pellet line that also expands the manufacturer’s production capacity for their Einar ® brand plant-based polymer additives. “We are seeing a fast-growing demand among consumers, brand owners, packaging designers and plastics manufacturers for more natural materials to reduce fossil depletion and waste,” says Ulrik Aunskjær, Global Industry Director Non-Food Business Development, Polymer Additives for Palsgaard. “Our expanded production capacity meets these requirements by boosting the availability of food-grade plant-based surfactants and modifiers for polymer manufacturers and compounders.” The expansion of the pellet line also addresses the needs of compounders and processors who may wish to add specific Einar products to polymers directly rather than as part of a more complex masterbatch formulation. This applies in particular to the use of Einar anti-static additives for food and other packaging applications, where the availability of pelletised products enables a clean and straightforward process. Palsgaard offers its Einar plant-based anti-fog and anti-static additives in several grades tailored to film, injection moulding, foam, and coating processes for a wide range of different polymers, from polyolefins and PVC to PET and engineering plastics. Moreover, the Einar portfolio also includes slip additives, ageing modifiers, mould release agents, and dispersing aids. Ulrik Aunskjær added: “We have a number of new initiatives, including establishing a solar park and a biogas facility, which will provide the necessary power and waste management infrastructure to enable the new production capacity to also be carbon neutral. This aspect was a very important consideration in the planning process for the new investment.” The company is currently the world’s only commercial source of fully sustainable emulsifiers and additives based on RSPO SG-certified palm oil as well as rapeseed, sunflower, and other vegetable oils. All products are non-GMO, have full EU and FDA food contact approvals, and meet halal and kosher requirements. AT New route to prepare biobased polyesters with tunable properties In a paper published in ACS Sustainable Chemistry & Engineering, researchers from the Kleij group of the ICIQ research institute (Tarragona, Spain) presented a new route to prepare biobased polyesters with tunable properties. The researchers are building upon the multifunctional structure of the terpene β-elemene: three double bonds which have distinct reactivity, allowing to selectively transform these bonds and thus tweaking the functionalities in the backbone of the polymer. "This multi-functional terpene scaffold is rather unique and allows to fine-tune structural diversity and prospectively to modulate polymer and material properties," explains Arjan Kleij, ICIQ group leader and ICREA professor. In collaboration with the company Isobionics (Geleen, The Netherlands), the researchers utilised β-elemene obtained through an innovative sugar-fermentation route. This process has proven to be a promising start for the use of β-elemene as a raw material for polymerisation. "Isobionic's sugar-fermentation route completely changes the scale of β-elemene availability, which now can be used in polymer production," explains Francesco Della Monica, postdoctoral researcher in the Kleij group working in the European SUPREME project, an MSCActions Individual Fellowship and first author of the paper. Via a ring-opening copolymerisation reaction (ROCOP), the researchers combined β-elemene oxides and phthalic anhydride (a common monomer used in the preparation of polyesters) to create the biobased linear polymer poly(BEM-alt-PA) and its related structure, crosslinked-poly(BED-alt-PA). These transformations were achieved with catalytic systems (iron and aluminium aminotriphenolate complexes combined with bis-(triphenylphosphine) iminium chloride) developed previously by the group using non-critical, abundant elements for catalytic polymerisation. Once the polyester is prepared, there are two remaining double bonds from the original terpene building block that can be easily and selectively addressed and functionalised, allowing to tailor the final polyester. "These post-modification reactions on a biobased polymer are quite rare. Most of the biobased monomers that are available don't present functionalities," remarks Della Monica. The paper is a starting point for further development of β-elemene based polymers that allow tailoring the properties of the final material (depending on its use) through easy post-polymerisation modifications. The paper does not address the biodegradation of the material, although for Della Monica, "depending on the final use, the ideal thing may not be biodegradation but to create a recyclable polymer: i.e., take a starting material, create the polymer, use it, recover it, and then degrade it in a controlled fashion and reuse that material. Now that we have the idea of a circular economy within grasp, we need circular processes," concludes the scientist. AT | Material News bioplastics MAGAZINE [02/21] Vol. 16 43

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