Das Institut für Allgemeinen Maschinenbau der TH Köln entwickelt mit einem Industriepartner ein nachhaltigeres Verfahren, das Materialien für das Wiederverwerten von Bremsbelägen aufbereitet.Weiterlesen...

Rubber is used in numerous applications and due to this, different recipes are needed. For each recipe used, an individual mixing instruction has to be developed. The development of them is often based on personal knowledge. In order to generate mixing instructions in the future, the mixing process was investigated and modeled. Therefore, mixing tests were carried out using different process parameters. Based on the resulting fingerprint, the temperature development of the natural rubber during the mastication was modeled. Further, a prediction was created to forecast the mixing time required until carbon black is fully incorporated into the polymer matrix after carbon black addition.Weiterlesen...

Das Mehrkomponentenspritzgießen von Flüssigsilikonkautschuken (LSR) mit Thermoplasten, wie PBT oder Polyamid ist Stand der Technik und wird bei vielen Bauteilen in der Automobilindustrie und im Bereich der Sanitärtechnik im Herstellungsprozess angewendet. Standardthermoplaste, wie z. B. Acrylnitril-Butadien-Styrol (ABS) lassen sich wegen ihrer niedrigen Erweichungstemperatur bisher nicht mit Silikonkautschuken im Spritzgießverfahren verbinden. In diesem Beitrag wird anhand von medizintechnisch zugelassenen ABS-Typen gezeigt, wie man mit einer dynamischen Werkzeugbeheizung und verschiedenen Vorbehandlungsmethoden für die Thermoplast-Oberflächen ABS-LSR Probekörper herstellen kann. Zudem wird aufgezeigt, welchen Einfluss die Sterilisation solcher Bauteile auf den Haftverbund hat.Weiterlesen...

The current research aims to improve the accuracy of results obtained from a pin-on-disc tribometer by using stepper motors and linear actuators. Additionally, the research focuses on enhancing the tribological properties of ­PMMA by reinforcing it with 0.1, 0.2 and 0.3 wt% SWCNT or MWCNT. The researchers prepared cylindrical-shaped nanocomposite samples and subjected them to friction and wear tests using a pin-on-disc tribometer with stainless steel disks as counterparts. The results showed that the PMMA matrix containing 0.2 wt% of SWCNT and 0.1 wt% of MWCNT exhibited the best tribological properties with reduced friction coefficient and wear rate.Weiterlesen...

With a test rig developed at the IKV, the resonance frequency of small sheets of rubber can be measured in seconds. The measuring principle has the potential to be used to monitor the degree of cross-linking on-line. In order to evaluate the suitability of the resonance frequency for this measurement task, the hardness, compression set, static spring constant and loss factor were measured on pressed sheets in addition to the resonance frequency, and anisothermal relaxation tests were carried out. The tests confirm the applicability of the resonance frequency to determine the degree of cross-linking.Weiterlesen...

Projectile injection technology (PIT) is a new approach for the production of hollow rubber parts that is already used in thermoplastics processing. However, there have been very few investigations on the PIT processing behaviour of rubber compounds. The flow and curing behaviours are mainly responsible for the surface quality achievable and residual wall thickness. Different compounds were chosen according to the projected applications.Weiterlesen...

Dem Fraunhofer IPA ist es zusammen mit der Uni Paderborn und Siegwerk gelungen, biogene Pigmente aus Chitin und biobasierte Farbstoffe herzustellen.Weiterlesen...

We describe a modelling approach to the calculation of dynamic moduli of filled elastomers based on filler morphologies derived from the experimental interface tensions of the material‘s components. The proposed approach consists of two main parts. The first one is a Monte Carlo-based morphology generator, which is used to build model compounds on the µm-scale. In the second part, the Monte Carlo morphologies are mapped onto a topologically identical model, allowing to obtain the dynamic moduli. This combination of models ties the experimental surface tensions, characterizing the individual components, to the dynamic behavior of the macroscopic material.Weiterlesen...

By determining characteristic maps that describe the wall slip as a function of the compound composition and the extrusion temperature, boundary conditions in flow simulations can be determined in such a way that the effects on pressure and temperature distribu-tion in the extrusion process are considered. This enables an improved die design with fewer iteration steps. In addition, by means of a 2D simulation of the exit geometry, which only requires the pressure loss in the die as an input variable, the die geometry can be determined with minimal computing times in such a way that the extrudate geometry after swelling corresponds to the desired profile geometry.Weiterlesen...

An essential component in an earthquake-resistant building is a seismic base isolator. Nowadays, seismic base isolators are usually produced from synthetic rubber such as Chloroprene Rubber (CR). This research investigated the possibility of combining CR and natural rubber. Specimens were prepared with different ratio compositions of CR and NR (SIR20). Surprisingly, the mechanical properties of 100 phr SIR20 fulfill the specification of the seismic base isolator. Dynamic Mechanical Analysis was also performed in the predominant earthquake frequencies. The mechanical and dynamic properties change slightly with temperature and frequency variations, which means the material is stable and predictable as seismic base isolators. The high loss factor indicates high damping properties, which is crucial in selecting seismic bearings.Weiterlesen...