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Similarities in Stress-Strain-Curve and electrical Conductivity
Electroconductive composites were prepared using either styrene–butadiene rubber or polycaprolactone matrix with varying amounts of two grades of electroconductive carbon black. Electrical conductivity was measured during deformation and at the same time a stress-strain-curve was recorded. The dependences of electrical conductivity on deformation exhibit several extremes. All conductivity changes were interpreted in terms of either the conductive pathways destruction or the formation of new ones, Thus, electrical conductivity can be correlated with the specific features of the physical network of the reinforcing filler that affect the mechanical properties of the composite.Weiterlesen...
Molecular-Scale Polymer Melts Response to shear in the linear and non-linear rheological
The molecular-level response to shear of entangled polymers at interfaces and in the bulk has been of interest to understand the non-linear rheological response of polymers. Here we focus on the molecular level response to shear strain leading non-linear rheological phenomenon, in linear and star polymers comparing the observed response to the predictions of tube theory. We used SANS measurements of the bulk polymer response to shear in Couette geometry on melts of high molecular weight mixtures of polymers extending our previous results on interfacial responses with rheoNR measurements in cone-and-plate geometry.[1, 2] further development of the theory.Weiterlesen...
Influence of Process Parameters on the Curing of Polyurethanes by dielectric Measurements
The Polyurethane Reaction Injection Molding (PU RIM) process is currently still reliant on a high level of know-how, both in the case of quality deviations of the product and in the initial configuration of molds. PU manufacturing hardly uses the established sensor technologies that are common in injection molding. In a research project at the Institute for Plastics Processing (IKV), the influence of the process parameters component temperature, mold temperature, material output speed and mixing ratio on the curing behavior of compact polyurethane coating systems is being experimentally investigated by means of dielectric measurements. The results show that for all variations of the process parameters investigated, the influence on the curing reaction could be successfully detected.Weiterlesen...
Evaluation of the Reinforcement Mechanism of functionalized Nanoparticles in Silica loaded Rubber Compounds
The performance of nano-sized rubber particles with different functional groups was studied in a silica loaded tire tread compound. The nanoparticles contained hydroxyl-, carboxyl-, dimethyl amino-, pyridino-, or epoxy- groups. In uncured compounds the reduction of filler flocculation at 160°C was mostly pronounced by nanoparticles, which contained either carboxyl or hydroxyl groups. In vulcanizates, the best filler dispersion and the best combination of mechanical and dyn.- mechanical properties were obtained with nanoparticles with OH-groups. As the silanization of the OH-groups is much slower than that of the silanol groups the OH-groups of the nanoparticles are practically not silanized at the end of the compounding procedure.Weiterlesen...
Additive Manufacturing of Rubber Parts based on low viscous Compounds using a Direct-Ink-Writing Process
This paper deals with investigations into the additive manufacturing of an EPDM-based high-viscosity sulfur-curable rubber compound. In order to make the compound processible using „Direct-Ink-Writing“, different solvent concentrations are used to reduce the compound viscosity to the limited process window. For 3D-printing process variable process parameters are used to optimize the quality of the rubber part, which is controlled by laser confocal microscope, 3D-µ-CT and physical properties. In addition, the effect of residual solvent in the polymer, respectively in the semi-finished product, affect the possible volume shrinkage caused by evaporation processes of the printed part during vulcanization.Weiterlesen...
Synthos schreibt internationalen Forschungspreis aus
Die Ausschreibung von Synthos richtet sich an Wissenschaftler, die im Bereich nachhaltiger syntetischer Kautschuke, Hochleistungselastomere und/oder Reifenmischungen promovieren.Weiterlesen...
Wie ein Silikonschwamm unbekannte Bakterien aufspürt
Von unserem Darm bis hin zum Meeresgrund: Mikroorganismen bevölkern nahezu jeden Lebensraum, sei er auch noch so feindlich. Für die Biotechnologie und die Medizin birgt die Vielfalt ihrer Überlebensstrategien großes Potenzial.Weiterlesen...
Effect of Rubber Elasticity on humanoid Robot Walking Stability
Walking is an inherent ability used by humans for locomotion. Human walking consists of alternating cycles of contact with the ground to avoid unbalancing that depends on a synergy between the feet muscles and joints, in addition to the texture and hardness of the foot surface.Weiterlesen...
Property Enhancement of NR/Halloysite Nanotubes Composites by Introducing dual Modification
As the performance of natural rubber (NR) and halloysite nanotube (HNT) composites is uncertain due to low compatibility between the materials, Maleated NR (MNR) is then used as a compatibilizer to encourage filler-rubber compatibility.Weiterlesen...
Ozonrissbildung bei Elastomeren – Eine Übersicht
Die Ozonrissbildung von Elastomeren basiert auf der chemischen Reaktion von Ozonmolekülen mit den C=C-Doppelbindungen der Polymermatrix. Die makroskopisch erkennbare Rissbildung und das Risswachstum variieren jedoch stark mit vorliegenden Umweltbedingungen.Weiterlesen...