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Enhancing the Strength and Wear Resistance of Rocca Oil based Epoxy/TiO2 NPs Matrix as Eco-Friendly Reinforcements
This study investigates the mechanical, physical, and wear-resistant properties of different epoxy composites. An epoxy matrix is used as the base material, while a combination of rocca natural oil and TiO2 nanoparticles is used as filler. The experiments include XRD analysis, hardness measurements, stress-strain curve analysis, friction coefficient and wear rate calculations and topography examination of worn surfaces using optical 3D and SEM imaging. The results show that the hybrid filler is well-dispersed throughout the matrix according to XRD analysis. Additionally, filling the matrix with 1.5 % TiO2 nanoparticles and 10 % rocca/epoxy matrices increases the hardness value by approximately 13.3 %. The lowest friction coefficient and wear rate were found in the sample filled with 10 % rocca oil and 1 % TiO2 nanoparticles, with reductions of 61 % and 70 %, respectively.Weiterlesen...

Perspective Application of Biopolymers as Components of Rubber Compounds
Biodegradable and environmentally friendly polymers made from renewable raw materials are now the preferred choice for a wide range of applications. However, a combination of petroleum and bio-based sources is now being studied for developing cost-effective and environmentally friendly rubber products, with a specific pursuit of the European Green Deal. This research is focused on the application of calcium lignosulfonate into NBR rubber. The incorporation of plasticizer into the rubber compounds aimed to plasticize the biopolymer, to achieve a higher degree of homogeneity, improve the interfacial adhesion between the biopolymer and rubber matrix, and consequently achieve improved mechanical properties. The obtained results clearly show that it is possible to incorporate calcium lignosulfonate into the rubber matrix and to achieve the required characteristics of prepared vulcanizates.Weiterlesen...

Single-Stage Profile Coextrusion of Rubber and Thermoplastics into recyclable Sealing Profiles
In a research project, the single-stage coextrusion of EPDM and PE-LD was realised. A novel coextrusion die was designed rheologically and thermally. During the co-extrusion trials, the die temperature and the screw speed were varied. Subsequently, the rubber was vulcanised by microwave and infrared radiation, which could easily be stopped from heating up the thermoplastic. It could be shown that coextrudates of EPDM and PE-LD can be produced in a reasonably stable extrusion process. The adhesive strength of the two layers was so high that it was not possible to carry out peeling tests. The material combination offers the possibility of reusing rejected production runs as a TPE material.Weiterlesen...

Characterization of Material Inhomogeneities
The aim of the present work was the spatial characterization of potential inhomogeneities in epoxidized NR (e-NR) / solution SBR (s-SBR) rubber blends caused by crosslinking. In addition to micro-indentation and atomic force microscopy (AFM), the investigated samples were also characterized by TEM, DSC and physical testing methods. The investigated rubber blends were prepared with different polymer ratios and variations in the crosslinking system. The morphology and miscibility of the polymers were characterized as a function of the mixing parameters used. The systems are clearly two-phases, based on the polarity of the individual polymers. The investigated crosslinking systems, show a higher efficiency or solubility in the e-NR-phase.Weiterlesen...

Messmethodik zur Bestimmung der Entropieverringerung deformierter FKM-Probenkörper und FEM-Software-Implementierungsansatz
Mittels Dynamisch-Mechanischer-Ana-lyse (DMA), d. h. über eine statische Versuchsführung und nichtisothermer Vorgehensweise, wird die indirekte Bestim-mung von Entropieverringerungen in Abhängigkeit des Deformationsgradienten des elastomeren Probenkörpers vorgestellt. Ein relativ einfacher, mathematischer Modellansatz erlaubt die Berechnung von Entropieverringerungen aus den Messwerten. Da die Entropieverringerung sehr materialspezifisch ist, müssen für jede Elastomermischung eigene Messungen durchgeführt werden. Es wird auch andiskutiert, wie sich die Entropieverringerung als Materialgröße in die Modellfunktionen von Simulationsprogrammen zur Finite Elemente Methode (FEM) implementieren lässt. Noch immer wird die Ausprägung des Gough-Joule-Effektes in deformierten Elastomerquerschnitten nur unzureichend bei Simulationsberechnungen berücksichtigt.Weiterlesen...

Direct Injection Molding Competitiveness Study
The direct injection molding concept leads to a drastic reduction in the number of steps by integrating material preparation and mixing into the injection molding process. The disadvantage of this concept is currently the insufficient miscibility of polydisperse materials in conventional injection molding machines. This study estimated the competitiveness of direct injection molding by equipping standard injection molding machine with special, so-called barrier screw with Maddock and kneading elements. Materials used for mixing are styrene-based elastomer, polypropylene and powder of calcium carbonate. Mixing quality was evaluated with x-ray microtomography, Shore A hardness tests and visual assessment. The study has shown that direct injection molding can be a perspective manufacturing approach.Weiterlesen...

Messung des Kompressionsmoduls von Silikon-Werkstoffen mittels eines entwickelten volumetrischen Kompressionsversuchs
Bei der Auslegung von Silikonbauteilen im Automotive-Bereich ist es wichtig, das mechanische Verhalten unter Zug-, Druck- oder Kombinationsbelastung vorherzusagen. In der Arbeit wird die Kompressibilität bzw. das Kompressionsmodul des Materials mittels eines volumetrischen Kompressionsversuchs untersucht. Dazu wird eine vorgeschlagene Prüfvorrichtung optimiert und ein einheitlicher Prozess entwickelt, um Fehler während des Versuchs zu vermeiden. Für die Arbeit werden ein Zweikomponenten-raumtemperaturvernetzender Silikonkautschuk (2K-RTV) und zwei Flüssigsilikonkautschuke (LSR) ausgewählt. Dazu wird der Einfluss von Tempern auf das Kompressionsverhalten von LSR untersucht. Außerdem wurde der Einfluss der zyklischen Belastung auf das Kompressionsmodul untersucht.Weiterlesen...

Effect of Temperature on the Stress Softening and Damping
This study aimed to identify the effect of temperature and co-agent type on the stress softening, energy dissipation, and damping properties of phenyl-methyl-polysiloxane (PVMQ) elastomers prepared with a peroxide curing system. We identified that temperature and type of the co-agent are two critical parameters controlling the damping properties of polymers and a decrease in temperature decrease of the damping capacity of silicone elastomer. Variation of co-agent type changes the elastomer‘s cross-link density, and high cross-link densities were observed in the presence of TAIC. However, although the type and the amount of co-agents changed the mechanical properties, they did not significantly change the damping properties.Weiterlesen...

Modification of Carbon Black to Improve Filler Dispersion
Carbon black surface chemistry was modified by treatment with benzyl tri-ethyl ammonium chloride (BTEAC) and effects of the same were studied in styrene butadiene rubber and butadiene rubber-based compound.Weiterlesen...

So entstehen lösbare Klebeverbindungen
Ein englisches Forscherteam hat einen wasserbasierten, reversiblen Klebstoff entwickelt, dessen Haftfestigkeit von der pH-Wert-Änderung abhängt. Ist der pH-Wert neutral, so haftet der Klebstoff, wird das Millieu sauer oder basisch, so löst sich die Verbindung.Weiterlesen...