@inproceedings{WiedlKarlingerSchemmeetal.2021, author = {Wiedl, Sebastian and Karlinger, Peter and Schemme, Michael and List, Manuela}, title = {Vergleich von unterschiedlichen Aufschmelzverfahren und die daraus resultierenden Eigenschaften f{\"u}r WPC-Spritzgussteile}, series = {Technomer 2021}, booktitle = {Technomer 2021}, publisher = {Technische Universit{\"a}t Chemnitz}, address = {Chemnitz}, isbn = {978-3-939382-15-7}, pages = {1 -- 13}, year = {2021}, abstract = {Leichtbau und ressourcenschonende Herstellungstechnologien sind zentrale Themen des 21. Jahrhunderts. Im Zuge dessen werden vermehrt Naturprodukte in der Kunststoffverarbeitung eingesetzt. Eine Sparte dabei bilden Holz-Polymer Werkstoffe (WPC), welche seit 2014 eine Verdoppelung in der Produktionsmenge erfahren haben. Dabei werden meist Holzpartikel statt Fasern als F{\"u}ll- und Verst{\"a}rkungsstoff eingesetzt. Der Vortrag befasst sich mit dem Vergleich von verschiedenen Aufbereitungsm{\"o}glichkeiten von WPCs mit Holzfaserverst{\"a}rkung hinsichtlich Mechanik und thermischer Sch{\"a}digung des temperaturempfindlichen Holzes. Teil der Untersuchung ist die einstufige Verarbeitung mittels eines Injection-Moulding-Compounders sowie die zweistufige Verarbeitung mittels Compounder und Heiz-K{\"u}hl-Mischer mit anschließendem Urformen an der Spritzgussmaschine.}, language = {de} } @article{WiedlKarlingerSchemmeetal.2022, author = {Wiedl, Sebastian and Karlinger, Peter and Schemme, Michael and List, Manuela and Ruckd{\"a}schel, Holger}, title = {Comparison of Melting Processes for WPC and the Resulting Differences in Thermal Damage, Emissions and Mechanics}, series = {Materials}, volume = {15}, journal = {Materials}, number = {9}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/ma15093393}, pages = {13}, year = {2022}, abstract = {The necessity for resource-efficient manufacturing technologies requires new developments within the field of plastic processing. Lightweight design using wood fibers as sustainable reinforcement for thermoplastics might be one solution. The processing of wood fibers requires special attention to the applied thermal load. Even at low processing temperatures, the influence of the dwell time, temperature and shear force is critical to ensure the structural integrity of fibers. Therefore, this article compares different compounding rates for polypropylene with wood fibers and highlights their effects on the olfactory, visual and mechanical properties of the injection-molded part. The study compares one-step processing, using an injection-molding compounder (IMC), with two-step processing, using a twin-scew-extruder (TSE), a heating/cooling mixer (HCM) and an internal mixer (IM) with subsequent injection molding. Although the highest fiber length was achieved by using the IMC, the best mechanical properties were achieved by the HCM and IM. The measured oxidation induction time and volatile organic compound content indicate that the lowest amount of thermal damage occurred when using the HCM and IM. The advantage of one-time melting was evened out by the dwell time. The reinforcement of thermoplastics by wood fibers depends more strongly on the structural integrity of the fibers compared to their length and homogeneity}, language = {en} } @misc{ListAltenbuchner2024, author = {List, Manuela and Altenbuchner, Stefan}, title = {Investigation of the color diffusion of beech wood treated with (natural) dyes}, year = {2024}, abstract = {Considering the growing demand from customers for a wider range of decorative furniture designs in the furniture industry, this study examines a method for enhancing beech wood by coloring it with (natural) dyes. The aim is to expand the range of colors available for furniture production and to meet the needs of customers for individual and diverse furniture pieces. The focus is on the dyeing process and the influence of various parameters such as pressure, impregnation time, type and concentration of dyes on the color intensity of the impregnation process. Additionally, the mechanical properties of the dyed beech samples, including hardness and tensile strength, are analyzed. Results indicate that a higher color intensity and improved color diffusion into the wood occur with increased pressure, longer impregnation time and higher dye concentration. Furthermore, the choice of colorant and its molecular size significantly impact the impregnation results.}, language = {en} } @misc{ListKoeck2024, author = {List, Manuela and K{\"o}ck, Maximilian}, title = {CO2 direct electrolysis to green ethylene „CODE"}, year = {2024}, abstract = {In 2019, approximately 810 million tons of CO2 were emitted in Germany, with the industrial sector alone accounting for 187 million tons [1]. An important goal is to achieve a comprehensive and sustainable use of CO2 sourced from waste gas (e.g. from cement production or wood gasification) as a raw material for the production of chemical base materials as an alternative to traditional fossil fuels. Using a new direct electrolysis method is an innovative and sustainable way of producing green ethylene. This process can create regional value chains, starting from reducing CO2 emissions, by sequestering it in sustainably produced ethylene, at local companies to utilizing the non-fossil raw materials for the chemical industry. The by-products, such as CO and hydrogen, also play a crucial role for further applications and processing. The process is based on a chemical redox reaction within an electrolysis cell. CO2 is reduced at the cathode, producing CO and other by-products such as hydrogen and ethylene, while water is oxidized at the anode, resulting in the production of oxygen. The resulting gas stream on the cathode side is separated, focusing on achieving a high yield and purity of ethylene. Various distillation and membrane technology processes can be used for this purpose. All gaseous and liquid products from the electrochemical cell are subjected to continuous analysis, largely carried out using a gas analyzer, gas chromatograph, and NMR. This decarbonization initiative not only helps to reduce carbon emissions, but also enables the environmentally friendly production of chemical base materials.}, language = {en} } @misc{ListMaurischat2024, author = {List, Manuela and Maurischat, Jan}, title = {Extraction of Protein-Based Biopolymers from Algae and Food Byproducts}, year = {2024}, abstract = {Protein-based biopolymers extracted from food by- and waste products, as well as algae offer an advantageous route to mitigate the influence of non-degradable plastics in the environment. This study focuses on the extraction of biopolymers from various algae species (Gracilaria spinuligeria., Auxenochlorella pyrenoidosa, and Spirulina platensis) and food by-products such as corn gluten meal and wheat gluten. The extraction process employs an organic solvent with a dielectric constant ε(25°C)= 42. Different concentrations of the starting material and varying extraction times were tested to optimize yield and quality of the biopolymers. The sample composition was analyzed using Py-GC/MS, HPLC, IC, TGA and elemental analysis. Results indicated that the chlorine concentration in the saltwater algae (Gracilaria spinuligeria) was excessively high, making it unsuitable for use due to the further concentration of chlorine in the extract. Additionally, the film-forming properties of biopolymers extracted from Gracilaria spinuligeria were less ideal compared to those derived from wheat and corn gluten. Spirulina platensis and Auxenochlorella pyrenoidosa lack a significant prolamin fraction and cannot be extracted as effectively as corn gluten meal and wheat gluten. The film forming capabilities and thermal properties of corn and wheat gluten film, as well as fresh water algae films, showed promising results. These findings suggest significant variations in the extraction efficiency and biopolymer characteristics based on the type of raw material and extraction parameters. These insights are crucial for the sustainable production of biopolymers, with potential applications in various industries, including food packaging and bioplastics.}, language = {en} } @misc{KreyZenzWideraetal.2024, author = {Krey, Adrian and Zenz, Vitus and Widera, Karolin and List, Manuela and Muscat, Dirk and Str{\"u}bbe, Nicole}, title = {Reactive Extrusion of Lignocellulosic Biomass to Produce Biopolymer Monomers using High-Energy Radiation and Catalytic Acids}, series = {Proceedings of the 39th International Conference of the Polymer Processing Society (PPS-39)}, journal = {Proceedings of the 39th International Conference of the Polymer Processing Society (PPS-39)}, editor = {Ediciones Uniandes,}, doi = {https://doi.org/10.51573/Andes.PPS39.SS.BBB.6}, pages = {329 -- 337}, year = {2024}, abstract = {The increasing prevalence of bio-based and biodegradable plastics as an alternative to traditional plastics derived from crude oil is a noteworthy trend. Polybutylene succinate (PBS), a plastic produced from succinic acid, is among the promising materials for the future. However, the production of bio-based succinic acid through biotechnical processes in controlled environments presents challenges. This process leads to increased costs and is currently not economically competitive compared to crude oil-based succinic acid production. In addition to succinic acid, levulinic acid is another monomer produced in the same process. A novel approach to the digestion of biomass has been developed to address the issue of biotechnological production of bio-based platform chemicals. This innovative process employs microwave radiation, pressure, and temperature to convert wood residues into succinic acid and levulinic acid. Various catalyst concentrations and biomass ratios were tested in a batch process, with high-pressure liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC/MS) analyses revealing the formation of succinic acid, levulinic acid, formic acid, and 2 oxoglutaric acid. The results demonstrate that microwaves combined with a metal salt catalyst can be used to produce platform chemicals from lignocellulosic biomass. To further advance the continuous production of PBS, a twin-screw extruder was modified and adapted after the successful results obtained from the batch processes. This setup enables additional experiments to evaluate the transferability of batch process results to continuous reactions, facilitating the scale-up and economic viability of the overall PBS production process in the future.}, language = {en} } @misc{WiedlSehySchmidetal., author = {Wiedl, Sebastian and Sehy, Michaela and Schmid, Thomas and Bonauer, Markus and M{\"u}ller, Norbert and List, Manuela}, title = {Neue Wege f{\"u}r WPC: Altholz und klimaresiliente Laubholzarten als alternative Verst{\"a}rkungsstoffe}, series = {Technomer 2025}, journal = {Technomer 2025}, editor = {Seefried, Andreas and Stommel, Markus}, pages = {46 -- 46}, language = {en} }