TY - JOUR A1 - Herrmann, Volker A1 - Blank, A. T1 - Dehnungsverhalten von Elastomeren mit Gummimehl JF - Gummi Fasern Kunststoffe GAK Y1 - 2017 VL - 70 SP - 726 EP - 736 ER - TY - JOUR A1 - Herrmann, Volker T1 - Nachhaltigkeit in der Gummi- und Reifenindustrie JF - Kautschuk Gummi Kunststoffe Y1 - 2023 VL - 76 SP - 8 EP - 9 ER - TY - JOUR A1 - Schülein, Tim A1 - Christos K., Georgantopoulos A1 - Bolk, Lars A1 - Herrmann, Volker A1 - Wilhelm, Manfred T1 - Thermo-Mechanical Degradation Kinetics of a High-Density Poly(Ethylene) Using a Closed-Cavity Rheometer JF - Journal of Applied Polymer Science N2 - Mechanical recycling of polymers is an essential aspect to achieve circular economy. High shear stress, excessive temperature, and long residence time during reprocessing cause thermo-mechanical degradation of the polymer. Therefore, it is important to understand and quantify this degradation kinetics. Common ways to simulate degradation are very time and material consuming and clear insights into the respective influence of temperature and shear stress on degradation are rare. Within this publication a method is developed using a commercially available, close-cavity rheometer to emulate processing conditions in a defined way. This allows monitoring and predicting the behavior of a high-density polyethylene (HDPE) and quantify degradation kinetics and changes in the polymer topology. HDPE is selected as a model polymer due to its large production and wide range of applications. Different treated samples are analyzed by various rheological methods. Additionally, molecular characterization is conducted. A kinetic model to predict the changes in the molecular weight as a function of in-phase shear stress, temperature and duration during treatment is presented. The calculated activation energy for the initiation reaction agrees with the activation energy for HDPE degradation from thermogravimetric analysis. This activation energy is lowered by in-phase shear stress, modified by a factor of 1.7 m3 mol−1. Y1 - 2025 U6 - https://doi.org/10.1002/app.56784 VL - 142 IS - 17 ER - TY - JOUR A1 - Herrmann, Volker A1 - Frosch, Stefan A1 - Schülein, Tim A1 - Grunert, Fabian A1 - Blume, Anke T1 - Sulfur Diffusion Studies Imitating Recycled Ground-Rubber-Containing Compounds JF - Polymers N2 - n-rubber properties of vulcanizates deteriorate in the presence of incorporated recycled ground rubber (GR). This behavior is partly explained by a possible diffusion of sulfur from the rubber matrix into the GR. Therefore, the sulfur concentration and, thus, the crosslink density in the matrix are reduced. This phenomenon was further investigated in this research work using two spatially resolved methods that supplement each other: the diffusion of soluble sulfur in GR-containing compounds was locally investigated via Micro X-Ray Fluorescence analysis. Viscoelastic properties were also determined spatially by the Micro Dynamic-Mechanical Indentation method. Combining the results of both methods, local concentrations of sulfur were related to local viscoelastic properties, revealing great differences in crosslink density at the interface between the GR and matrix material. In this way, it is shown that sulfur is capable of diffusing several mm, which locally doubles its concentration with respect to the sulfur content of the compound formulation. This, in turn, negatively impacts the homogeneity of crosslink density in both the matrix and GR, revealing a local increase in the elastic stiffness of 100 %. In addition, it was found that the vulcanization characteristics of the used polymers determine the amount of sulfur diffusion and, thus, the change in viscoelastic properties. Y1 - 2024 U6 - https://doi.org/10.3390/polym16223112 VL - 16 IS - 22 ER - TY - CHAP A1 - Herrmann, Volker T1 - Überlegungen und Ergebnisse zur intrinsischen Deformation von Elastomeren mit Gummimehl T2 - 113. Tagung der Regionalgruppe Süd der Deutschen Kautschuk Gesellschaft DKG, Würzburg Y1 - 2023 ER - TY - JOUR A1 - Herrmann, Volker T1 - Internationalisierung als mögliche Lösung für das Problem des Fachkräftemangels JF - Kautschuk Gummi Kunststoffe 77 Y1 - 2024 SP - 8 EP - 9 ER - TY - JOUR A1 - Herrmann, Volker A1 - Naß, Felix A1 - Lemmich, Sebastian A1 - Wachter, Florian T1 - Untersuchungen zur Heizzeitreduzierung bei der Herstellung von dickwandigen Gummibauteilen JF - FHWS Science Journal N2 - Die Untersuchung beschäftigt sich mit einer neuen Spritzgießtechnologie zur Herstellung von Bauteilen aus Elastomeren. Mit dieser Technologie sind kürzere Zykluszeiten bei gleichbleibenden Bauteileigenschaften möglich. Die Höhe der Heizzeitreduzierung hängt von der Art der Bestimmung derselben ab und wird in der vorliegenden Arbeit auf unterschiedliche Weise quantitativ bestimmt. Je nach Verfahrensparameter und Bestimmungsmethode treten Heizzeitreduzierungen von maximal etwa 40 % auf. Weiterhin werden Untersuchungen an den hergestellten Bauteilen durchgeführt, welche die Interpretation des Ausmaßes und der Qualität der Vernetzungsdichte über dem Probenquerschnitt erlauben. Es können deutliche Heizzeiteinsparungen bei mindestens gleichbleibenden und teilweise homogeneren Vernetzungsdichten über dem Querschnitt eines dickwandigen Elastomerbauteils attestiert werden. KW - Schererwärmung KW - Reaktionskinetik Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:863-opus-1061 VL - 2 (2014) IS - 1 SP - 84 EP - 97 ER - TY - CHAP A1 - Herrmann, Volker A1 - Möginger, Bernhard A1 - Unseld, Claus ED - Zacharias, Christoph T1 - Quasi Static Indentation Measurements: A Tool for Micromechanical Investigations of Interfaces in Polymer Materials T2 - Forschungsspitzen und Spitzenforschung N2 - The ongoing miniaturization, multi-layer structure parts and hybrid parts require methods to determine mechanical properties on a micro-scale. However, there is a gap in measuring techniques. On one hand there are the classical methods to measure hardness e.g. VICKERS, ROCKWELL, UNIVERSAL, IRHD etc having resolutions typically above 100μm. On the other hand there are well-developed AFM methods that allow for the determination of mechanical properties in the nanometer range. This paper describes an indentation technique that yields data of mechanical properties in the micrometer range between typically 5 to 50 μm. The measuring device and the data evaluation is presented. Results of micro-mechanical mapping are shown for NR-SBR rubber interfaces, a fuel tank and a part manufactured by two component injection moulding. Finally, the measured micro-mechanical stiffness is compared to the YOUNG’s modulus of the corresponding materials. Y1 - 2009 UR - http://permalink.bibkatalog.de/BV035327025 SN - 978-3-7908-2126-0 U6 - https://doi.org/https://doi.org/10.1007/978-3-7908-2127-7_28 SP - 315 EP - 327 PB - Physica CY - Heidelberg ER - TY - JOUR A1 - Herrmann, Volker A1 - Moldovan, Dumitrita A1 - Fechete, Radu A1 - Demco, Dan Eugen A1 - Culea, Eugen A1 - Blümich, Bernhard A1 - Heinz, Manfred T1 - Heterogeneity of Nanofilled EPDM Elastomers Investigated by Inverse Laplace Transform 1H NMR Relaxometry and Rheometry JF - Macromolecular Chemistry and Physics N2 - The heterogeneous effects due to filler interactions and chain dynamics of reinforcing nano-filler particles were characterized on a series of filled EPDM elastomers using the Payne effect and low field NMR, 1H transverse (T2), longitudinal (T1) and longitudinal in rotating frame (T1ρ) relaxation time measurements. Measurement of the Payne effect and NMR relaxation curves were used to obtain the distribution of filler/filler interactions and chain dynamics by one-dimensional Laplace inversion. Distributions of shear-strain constants in the Payne effect reveal the existence of weak, medium and strong filler/filler interactions which were correlated to filler properties and content. The analysis of relaxation-time distributions leads to the identification of multimodal polymer network dynamics. Y1 - 2010 U6 - https://doi.org/https://doi.org/10.1002/macp.201000086 VL - 211 IS - 14 SP - 1579 EP - 1594 ER - TY - JOUR A1 - Herrmann, Volker A1 - Moldovan, Dumitrita A1 - Fechete, Radu A1 - Demco, Dan Eugen A1 - Culea, Eugen A1 - Blümich, Bernhard A1 - Heinz, Manfred T1 - The heterogeneity of segmental dynamics of filled EPDM by 1H transverse relaxation NMR JF - J. Magn. Res. Y1 - 2011 U6 - https://doi.org/https://doi.org/10.1016/j.jmr.2010.10.019 VL - 208 IS - 1 SP - 156 EP - 162 ER - TY - JOUR A1 - Herrmann, Volker A1 - Niedermeier, W. T1 - Interpretation of Filler Networking of Loaded Rubbers via Mastercurves JF - Kautschuk Gummi Kunststoffe Y1 - 2010 UR - http://permalink.bibkatalog.de/BV002571657 VL - 63 SP - 559 EP - 564 ER - TY - JOUR A1 - Herrmann, Volker T1 - Moderne Elastomere JF - Ingenieurspiegel Y1 - 2009 IS - 3 SP - 100 EP - 101 ER - TY - JOUR A1 - Herrmann, Volker A1 - Heinrich, A. T1 - Influence of the modification of ground truck tyres as an additive on the properties of a truck tread compound JF - International Polymer Science and Technology N2 - Commercially available ground tyre rubber (GTR) made exclusively from post-consumer truck tyres was mixed into a typical truck tyre tread compound. As already shown in a previous study, this leads to a distinct deterioration in properties. The goal of the present investigation was to minimise these property losses through modification of the GTR in terms of processing methods. Modification methods already documented in the literature were used, e.g. application of sulphur and crosslinking agents to the GTR and the use of trans-polyoctenamer as well as liquid polymers, which in principle provide the potential for crosslinking of the GTR and polymer matrix through the availability of double bonds. For some methods of modification, small improvements are observed in comparison with the unmodified GTR. However, none of the GTR modifications reaches the level of the reference compound without GTR. An economic estimate for the modification with the highest potential for technical success shows that, in practice, considerable costs must be expected. Y1 - 2017 U6 - https://doi.org/10.1177/0307174X1704400501 VL - 44 IS - 5 SP - T/1 EP - T/9 ER - TY - JOUR A1 - Herrmann, Volker A1 - Schulz, A. T1 - Der Einfluss von Lkw-Reifenmehl als Additiv auf die Eigenschaften einer Lkw-Laufflächenmischung JF - Gummi Fasern Kunststoffe GAK N2 - Commercially available ground tire rubber (GRT) was mixed into a typical truck tire tread compound. The GRT originated from postconsumer truck tires and differed in the manufacturing process (cryogenic and warm grinding, resp.) as well as the ageing state. Regardless of the grinding process type, the vulcanizates containing GRT became softer, mechanical properties and the abrasion resistance worse and the Payne effect decreased. Additional artificial ageing of the GRT showed no further effects regarding property changes when adding GRT. Based on the vulcameter curves it could be seen, that the curing behaviour of the compounds changed and the crosslink density of the matrix obviously decreased by adding GRT. Additional ¡jXRF images and measurements for dynamic local indentation indicated increased sulphur content inside the GRT particles. Y1 - 2016 VL - 69 SP - 698 EP - 705 ER - TY - JOUR A1 - Herrmann, Volker A1 - Naß, Felix A1 - Lemmich, Sebastian A1 - Wachter, Florian T1 - Einfluss des EFE-Spritzsystems auf Heizzeitreduzierung und Eigenschaften der gespritzten Bauteile - Teil 1: „Betrachtung der Heizzeitreduzierung über reaktionskinetische Berechnung und begleitende Untersuchungen zu Bauteil- und Vernetzungsdichte mittels NMR-Bildgebung“ JF - Gummi Fasern Kunststoffe GAK Y1 - 2013 UR - http://permalink.bibkatalog.de/BV002585962 VL - 66 SP - 37 EP - 42 ER - TY - JOUR A1 - Herrmann, Volker A1 - Naß, Felix A1 - Lemmich, Sebastian A1 - Wachter, Florian T1 - Einfluss des EFE-Spritzsystems auf Heizzeitreduzierung und Eigenschaften der gespritzten Bauteile - Teil 3: „Abschätzung der Scherenergie und Einfluss der Drossel auf ausgewählte Eigenschaften der gespritzten Bauteile“ BT - Teil 3: „Abschätzung der Scherenergie und Einfluss der Drossel auf ausgewählte Eigenschaften der gespritzten Bauteile“ JF - Gummi Fasern Kunststoffe GAK Y1 - 2013 UR - http://permalink.bibkatalog.de/BV002585962 VL - 66 SP - 180 EP - 184 ER - TY - JOUR A1 - Herrmann, Volker A1 - Naß, Felix A1 - Lemmich, Sebastian A1 - Wachter, Florian T1 - Einfluss des EFE-Spritzsystems auf Heizzeitreduzierung und Eigenschaften der gespritzten Bauteile - Teil 2: „Einfluss der Verfahrensparameter des Spritzgießprozesses auf die Heizzeitreduzierung“ JF - Gummi Fasern Kunststoffe GAK Y1 - 2013 UR - http://permalink.bibkatalog.de/BV002585962 VL - 66 SP - 108 EP - 112 ER - TY - JOUR A1 - Herrmann, Volker A1 - Heinrich, A. T1 - Einfluss der Modifikation von LKW-Reifenmehl als Additiv auf die Eigenschaften einer LKW-Laufflächenmischung JF - Gummi Fasern Kunststoffe GAK Y1 - 2017 VL - 70 SP - 88 EP - 95 ER - TY - JOUR A1 - Herrmann, Volker A1 - Speyer, Y. A1 - Leiber, J. T1 - Herstellung und Verarbeitung von sortenreinem Gummimehl im Labormaßstab JF - Gummi Fasern Kunststoffe GAK Y1 - 2017 VL - 70 SP - 240 EP - 247 ER - TY - JOUR A1 - Herrmann, Volker A1 - Schulz, A. T1 - Influence of ground truck tires as an additive on the properties of a truck tread compound JF - Rubber Fibres Plastics RFP Y1 - 2018 VL - 13 SP - 24 EP - 30 ER -