TY - CHAP A1 - Herz, Jonas A1 - Lorenz, Katharina A1 - Muscat, Dirk A1 - Strübbe, Nicole T1 - Polymeric core-shell and mono-material fibers for concrete reinforcement T2 - AIP Conference Proceedings N2 - A reinforcement of concrete structures is needed because of the low tensile strength of concrete. Corrosion of the usually used steel reinforcments cause issues during time. Therfore, alternative reinforcements produced from non-corosive materials - like polymer fibers - become more interesting. A polymer fiber has to reach high mechanical properties and a good bonding ability to concrete. Both properties can be influenced by the selection of polymer and the used production process. Two polymers, polypropylene and aliphatic polyketone are tested within this study. First mono-material fibers of each material are produced and tested, later the materials are combined in a core-shell fiber. All fibers are produced by standard extrusion or coextrusion and a later drawing process. The mechanical properties are determined by tensile tests. The calculation of interfacial shear strength from single fiber pull-out tests allows an evaluation of the bonding ability. Additionally, fiber surface before and after pull-out is examined using reflected light microscopy. Contact angle measurements are done to evaluate possible influences of the surface energy and polarity. Density measurements are used to compare weight potential of the different mono-material and core-shell fibers. The results show good mechanical properties for all fiber materials. The interfacial shear strength is ≈ 2-3 times higher for fibers with polyketone compared to the ones with polypropylene at the fibers surface, which can be explained by higher surface energy and polarity of the polyketone compared to polypropylene and different surface deformation during pull-out. Lower densities are reached by fibers containing polypropylene. KW - polymer fibers KW - concrete reinforcement KW - core-shell fiber KW - coextrusion KW - polypropylene KW - polyketone Y1 - 2024 U6 - https://doi.org/10.1063/5.0204946 VL - 3158 IS - 1 ER - TY - CHAP A1 - Herz, Jonas A1 - Sigrüner, Michael A1 - Muscat, Dirk A1 - Strübbe, Nicole T1 - Co-extruded polymer fibers for concrete reinforcement T2 - Proceedings of the 37th International Conference of the Polymer Processing Society (PPS-37) N2 - Corrosion of steel reinforcements in concrete constructions is a big topic for the building industry. Polymeric materials are a possible alternative due to their ability to withstand corrosion. To replace steel reinforcements, fibers with high mechanical properties and a good bonding ability between fiber and concrete are needed. Today different approaches for concrete reinforcement by polymer fibers have been investigated. The bonding ability of the fibers can be increased by mechanical anchoring, e.g. crimped or embossed fibers, as well as by a chemical bonding between concrete and fiber surface. To realize the requirements of high mechanical properties and a good bonding behavior, a fiber that is drawn from a co-extruded filament shall be produced and tested. The filament owns an innovative core-shell-structure. The core maintains the fiber-stiffness and the tensile strength while the shell allows using another material to affect the bonding behavior of the fiber. This study shows the usage of fibers with differing shell materials to examine their influence on the mechanical properties of the fiber in total and the adhesion abilities to concrete. As core material, an unfilled polypropylene (PP) is used. The shell materials are varied using different polymers e.g. polypropylene or ethylene acrylic acid copolymer, as well as two PP based compounds filled with wood particles and calcium carbonate blended with a maleic anhydride based coupling agent. The mechanical properties of the fibers are tested by fiber tensile tests to compare the younǵs modulus and the tensile strength. The influence of the shell phase on the bonding ability to concrete is evaluated by the interfacial shear strength calculated from single fiber pull-out tests. Microscopy is used to interpret changes before and after pull-out. The results depict incredible positive effects and allow new insights in possible materials for fiber reinforced concrete constructions. KW - polymer fibers KW - concrete reinforcement KW - coextrusion KW - core shell fiber Y1 - 2023 U6 - https://doi.org/10.1063/5.0168511 VL - 2884 IS - 1 ER - TY - CHAP A1 - Schusser, Verena A1 - Sigrüner, Michael A1 - Bogner, Stefan A1 - Muscat, Dirk A1 - Strübbe, Nicole T1 - Effect of Fillers on the Mechanical Properties of Drawn Polypropylene Fibers T2 - International Conference on Composite Materials Belfast 2023 (ICCM 23), 30 July - 4 August 2023 KW - Filler Reinforcement KW - Filament KW - Fiber Draw Down Y1 - 2023 ER - TY - CHAP A1 - Zenz, Vitus A1 - Muscat, Dirk A1 - Strübbe, Nicole T1 - Development of a new granulate feeding system for gas pressurized extrusion processes T2 - ANTEC 2023 N2 - One major problem of a continuous process like plastic extrusion is their incapability to deal with non-local gas pressure. This is an inherent problem because a continuous process has an open end in the feeding port where pressure can escape. In this study a novel feeding system was developed to enable granulate feeding into gas pressurized processes inside a single- or twin-screw extruder. With this apparatus gas pressure can be applied inside the extrusion process. The apparatus separates the pressurized extruder from the dosing equipment that feeds the extruder. It keeps the pressure inside the system while continuously feeding new material into the process. A small-scale prototype was designed for proof-of concept. The small size of the prototype was able to handle small amounts of granulates of around 100 - 200 g/h. An applied gas pressure of 8 bar was achieved. In future optimizations, throughput can be increased and maximum applied gas pressure towards 15-20 bar. KW - Plastic feeding KW - Granulate KW - Extrusion KW - Compounding KW - Reactive Extrusion Y1 - 2023 PB - SPE ANTEC ER - TY - CHAP A1 - Herz, Jonas A1 - Sigrüner, Michael A1 - Walter, David A1 - Muscat, Dirk A1 - Strübbe, Nicole T1 - Coextruded Polymeric Bicomponent Fibers for Concrete Reinforcements T2 - SAMPE Europe Conference Proceedings 2022, Hamburg, 15. - 17. Nov. 2022 KW - Coextrusion KW - Bicomponent Fibers KW - Concrete Reinforcement KW - Polypropylene Y1 - 2022 ER - TY - CHAP A1 - Schmitz, Regine A1 - Haupert, Frank A1 - Rüthing, Justus A1 - Sigrüner, Michael A1 - Strübbe, Nicole T1 - Tribologische Charakterisierung von Polymerfasern unter Trockenreibung, Mischreibung und Hydrodynamik mittels einer optimierten Pin-on-Disc-Prüfmethode T2 - Tribologie und Schmierungstechnik N2 - Ausgehend von der herkömmlichen Pin-on-Disc-Prüfmethodik wurde ein Tribologieprüfstand hinsichtlich seiner Leistungsfähigkeit zur Fasercharakterisierung optimiert und angepasst. Die Methodik wird erläutert und erste Anwendungen im Bereich der tribologischen Charakterisierung von Einzelfasern werden vorgestellt. Der Prüfungsablauf zur Untersuchung der Polymerfasern, deren Durchmesser nur einige 100 µm betragen, ist so generiert, dass eine Erfassung der Daten als Funktion der Zeit im Bereich von einigen 10 µm bis zu einigen 100 µm Faserverschleiß kontinuierlich während der Messung bereits in den ersten Minuten erfolgen kann. Der Prüfmodus startet hierbei mit Linienlast und entwickelt sich dynamisch zur Flächenlast durch Änderung der Auflagefläche der Faser während der Messung. Es wird gezeigt, dass Einzelfasern hinsichtlich ihrer Reibungs- und Verschleißeigenschaften in unterschiedlichen tribologischen Systemen charakterisiert werden können. Die Abhängigkeit der Verschleißraten von Fasermaterial, Oberflächenrauheit der Gegenkörper und Schmiermittelraten wird dargestellt. N2 - Based on the conventional pin-on-disc test method, a tribology test rig was adapted and optimized regarding its ability to characterize polymer fibers. The method is explained and first applications in the field of tribological characterization of single fibers are presented. The test sequence to investigate the polymer fibers (diameters of only a few 100 µm) is generated in such a way that data can be recorded continuously as a function of time in the wear range from a few 10 µm to several 100 µm even during the first few minutes. The test mode starts by applying line load and dynamically progresses to area load by changing the contact area during the measurement. It is shown that single fibers can be characterized with respect to their friction and wear properties in different tribological systems. The dependence of the wear rates of fiber material, surface roughness of the counter bodies and lubrication rates is presented. KW - Oberflächenrauheit KW - Polymerfasern KW - Pin-on-Disc KW - abrasiver Verschleiß KW - Reibung KW - Wasserschmierung Y1 - 2021 UR - https://doi.org/10.24053/tus-2021-0015 VL - 68 IS - 3-4 SP - 13 EP - 21 ER - TY - CHAP A1 - Herz, Jonas A1 - Sigrüner, Michael A1 - Krekemeyer, Markus A1 - Kazmi, Monis A1 - Schuster, Jens A1 - Muscat, Dirk A1 - Strübbe, Nicole T1 - INVESTIGATION OF AN INNOVATIVE WOOD-PLASTIC HYBRID LAID FABRIC FOR THE REPLACEMENT OF STEEL REINFORCEMENTS IN CONSTRUCTIONS T2 - SAMPE Europe 2021 Conference, Baden/Zürich, 29. - 30. Sept. 2021 KW - wood-plastic hybrid fabric Y1 - 2021 ER - TY - CHAP A1 - Sigrüner, Michael A1 - Muscat, Dirk A1 - Strübbe, Nicole T1 - Influencing the bonding ability of polypropylene fibers to concrete by blend hydrophilization and reactive functionalization T2 - IUPAC MACRO2020+, 48th World Polymer Congress, 16. - 21. May 2021 KW - polypropylene fibers KW - concrete Y1 - 2021 ER - TY - CHAP A1 - Sigrüner, Michael A1 - Muscat, Dirk A1 - Strübbe, Nicole T1 - Investigation of the Bonding Behavior of Modified Polypropylene to a Concrete Matrix by Single Fiber Pull Out Tests BT - Amsterdam, Netherlands, 29 September – 1 October 2020 T2 - SAMPE Europe Conference Proceedings 2020 KW - Polypropylene KW - Single fiber pull-out test Y1 - 2020 ER -