Kautschuke

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Kautschuke

Rheology of Phosphorylated Cashew Nut Shell Liquid Prepolymer Modified Natural Rubber

Natural Rubber (NR) modified with Phosphorylated Cashew Nut Shell Liquid prepolymer (PCNSL) or with an aromatic oil shows an increased pseudoplasticity index and a decreased consistency index. The apparent melt viscosity of these systems decreases with increased temperature and shear rate and the activation energy for melt flow also decreases with rate of shear. Further, […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

Mechanical, Rheological and Morphological Properties of Recycled Expanded Polystyrene/Styrene Butadiene Rubber Blends

Mechanical, rheological and morphological properties of recycled expanded polystyrene/styrene-butadiene rubber (rPS/SBR) blends are studied. The SBR concentration was between 0 and 50 %. Properties of brittle rPS could be changed by SBR. At > 20 wt.-%, significant increases in elongation at break and impact strength were observed. Tensile strength, hardness and Tg decreased with increasing […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

Cross-link Clusters: reality or fiction? – A review of the state of the art, enlarged with recent AFM-data

One of the intriguing questions has always been how chemical rubber-networks really look like. One possible explanation for the fundamental differences in properties between sulphur and peroxide cured networks, is that the cross-links formed by either of the two tend to cluster leading to what we will call network heterogeneity. The paper gives an overview […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

Processability Characteristics of Linear and Branched Butyl Rubber1

Butyl samples with different degrees of branching and molecular weight were prepared in batch and continuous polymerization experiments. Branching was achieved using a bifunctional monomer. Molecular weight was controlled by the addition of a strong chain transfer agent. Samples were compounded with black filler and their processability was determined using cold flow, green strength, green […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

VPKA 8896: A new Short Term Tackifier in Peroxide-Cured EPDM Applications

The bonding model of pressure sensitive adhesives (PSAs) was used in the search for new tackifying materials which show superior peroxide compatibility compared to commercially available resins. As future developments, e. g. in belts, are directed towards higher temperature resistance combined with good dynamic properties, the request for new systems is often directed towards the […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

Evaluation of Natural Rubber and Cellulose II Compositions by Curing and Mechanical Properties

Rubber reinforcement increases if the domain size becomes less than 1 μm. Compositions of natural rubber and cellulose II were prepared by co-coagulation of natural latex and cellulose xanthate mixtures. The influence of increasing amount of Cel II, varying from 0 to 30 phr, on processing, curing and mechanical properties were studied. The use of […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

Combustion effluents of rubber, I. – Chemical analysis of compositions and influence of combustion parameters

Rubber fires are extremly hot and large amounts of smoke are emitted. Being able to predict the composition of fire effluents as a function of burning material and fire conditions is of great interest. Estimation of the hazard potential in the event of a fire and a judgement of compliance with statutes governing the storage […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

Einfluß von neuartigen Carbasulfan-Netzstellen auf das Eigenschaftsprofil von Dien-Kautschukvulkanisaten

Durch Modellvulkanisation von 2,3-Dimethylbuten-2 mit 1,6-Bis(N,N-dibenzyl-thiocarbamoyldithio)hexan (Vulcuren® VP KA 9188 der Bayer AG) und Strukturaufklärung der Reaktionsprodukte kann gezeigt werden, daß neuartige Carbasulfan-Netzstellen aufgebaut werden. Diese Ergebnisse stehen im Einklang mit Untersuchungen an ungefüllten NR-Vulkanisaten, bei denen die Schwefelbrückenlänge der Carbasulfan-Netzstelle durch Thiol-Amin-Methode bestimmt wurde. Das technologische Profil dieses bifunktionellen Vernetzers wurde im Hinblick auf […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

Phasenmorphologie und Relaxationsverhalten von SEBS/PP-Blends

Kommerzielle TPE‘s auf Basis von Styrol-Ethylen/Butylen-Styrol Blockcopolymeren stellen komplizierte Blends dar, in denen Füllstoffe, Weichmacher, Additive und als thermoplastisches Polymer meist Polypropylen enthalten sind. Es werden Modellmischungen aus SEBS und PP untersucht. Es wird gezeigt, dass die Phasenmorphologie der Blends entscheidend die mechanischen Eigenschaften, die thermischen Einsatzgrenzen und das Relaxationsverhalten beeinflusst. Zwei speziell zur Charakterisierung […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

The Reactive Compatibilization of EPDM-Based Elastomer blends

The reactive compatibilization of ethylene-propylene-diene (EPDM)-based dissimilar elastomer blends has been performed using mercapto-functionalized copolymers. The mercapto groups are able to react with the double bonds of the high diene rubber, resulting in a good interaction between phases. The mechanical properties of natural rubber/EPDM blends were significantly improved by the addition of 2.5 phr of […] mehr...

28.April 2003 - Neues aus der Forschung

Additive & Füllstoffe

Balanced Crosslink Network Created in Natural Rubber by using Sulphenamide/Tetrabenzyl Thiuram Disulphide Cure System

The durability of rubber goods often requires heat resistance in combination with good dynamic properties and adequate oxygen/ozone resistance. A proper balance of the network is important for flex and heat aging properties. The use of a binary system of accelerators such as sulfenamide and a commonly used thiuram such as Tetramethyl thiuram disulphide (TMTD) […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

New Indentation Methods for the Characterisation of Elastomer Composites

The investigation of elastomer composites is of great practical and basic interest. New indentation methods are introduced which allow to determine local mechanical properties of these systems. It can be shown, that marked inhomogenities of mechanical properties arise in elastomer-composites which consist of SBR and NR. These inhomogenities are investigated in dependence of the preparation […] mehr...

28.April 2003 - Neues aus der Forschung

Additive & Füllstoffe

Properties of EPDM/SBR Blends Cured with Peroxide and Sulfur Coagent

The objective of this study is to address the replacement of up to 30 parts of EPDM with SBR to reduce the cost of finished products and to improve selected blend properties using more efficient cure systems. Effects of sulfur, peroxide, and coagent curing systems on blend properties were studied. It was found that the […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

Innovationen auf dem Gebiet heißvulkanisierender, additionsvernetzender Silicon-Kautschuke

In den letzten Jahren haben sich zahlreiche Neuentwicklungen auf dem Gebiet der heißvernetzenden Kautschuksysteme im Markt etabliert. An erster Stelle sind dabei die Entwicklung von Platin-katalysierten Festsiliconen zu nennen. Diese weisen gegenüber traditionellen, peroxidisch vernetzten Systemen eine deutlich höhere Vernetzungsgeschwindigkeit auf. Eine weitere Neuigkeit ist die Entwicklung von rieselfähigen Festkautschuk-Granulaten, deren Einsatz eine hohe Automatisierung […] mehr...

28.April 2003 - Neues aus der Forschung

Kautschuke

Filmbildung von Latex-Systemen untersucht mit Hilfe von Streumethoden

Der Artikel behandelt die Analyse der räumlichen Ordnung eines getrockneten Polystyrol-Latex (Durchmesser: 106 nm) mit Hilfe der Röntgenkleinwinkelstreuung (small-angle X-ray scattering; SAXS). Das Trocknen des Latex wird unterhalb der Glastemperatur des Polystyrols durchgeführt, um auf diese Weise eine Deformation der Latex-Partikel bei Kontakt zu vermeiden. Die Analyse der Ordnung im System wird mit Hilfe des […] mehr...

28.April 2003 - Neues aus der Forschung

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