Konformationen eines ungedehnten (li) und eines gedehnten (re)  
Makromoleküls. (Bild: )
TESTING AND MEASURING

Prüfmethode zur Untersuchung thermoelastischen Verhaltens gespannter Elastomere 

Der Gough-Joule Effekt wird in einer verbesserten Prüfmethode genutzt, um auf die Entropieänderung und die absolute Vernetzungsdichte zu schließen. Im Gegensatz zu anderen Fachartikeln wird in dieser Studie bewusst der Weg über die klassische (ideale) Gummi elastizität gewählt, um eine möglichst einfach anwendbare Prüfmethode für den praktischen Gebrauch in der Materialentwicklung und -prüfung zu erhalten. Entropieelastizität und Vernetzungsdichte haben einen wesentlichen Einfluss auf diverse Materialeigenschaften und stellen somit wichtige Kenngrößen von Elastomeren dar. 

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General scheme of a tire pyrolysis 
process . (Bild: Orion  Engineered Carbons)
RAW MATERIALS AND APPLICATIONS

Carbon Black from Tire-Derived Pyrolysis Oil

Within the EU-funded innovation project BlackCycle (Horizon 2020 program, project number 869625), sustainable carbon blacks for tire applications have been produced on a conventional carbon black furnace reactor by using oils derived from an end-of-life tires pyrolysis process. This represents a truly circular process. The carbon blacks obtained show very similar analytical data and in-rubber properties in comparison to products produced with a standard oil.

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Schematic view of the free mixing energy against the volume fraction of the additive and its corresponding phase and stability diagram [2] (Bild: )
ELASTOMERS AND PLASTICS

Improved Contact Mechanisms of high Viscous Rubber Com pounds on Calender Roll Surfaces by using different Tackifier – Part 2

In Part 1 of this publication ( [1] KGK 3/2021) it was reported about different tackifier classes with regard to their performance to create tackiness in highly filled silica hard-rubber compounds for processing. In addition to influence the rheological properties of compounds, the migration- and blooming tendency during storage time is of high importance. Part 2 deals with the tack behavior in dependency of time, which is investigated and correlated with the chemical compatibility of different mixing ingredients in the compound. To estimate the tackifier so lubility in the used NBR the concept of Hansen Solubility Parameters was em ployed and compared with experimental results. 

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Fig. 1: Flow pattern in a calender-nip after Unkrüer [3] (Bild: )
TESTING AND MEASURING

Improved contact Mechanisms of high viscous Rubber Compounds on Calender roll Surfaces by using different Tackifier – Part 1

High viscous rubber compounds often lead to processing difficulties during ca lendering. The inefficient TACK behavior of the compound leads to premature detachment of the calendered slab and causes wrinkling and blistering, trapping of air and geometric fluctuations in thickness and width. The use of suitable tackifier can help to improve the tackiness of the compound to produce high-quality rubber sheets. The selection of a suitable tackifier also depends on the compatibility and interaction with the rubber compound. 

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Figure 1: General molecular structure of an EPDM rubber. (Bild: )
CONSTRUCTION AND SIMULATION

Statistical Approach of Designing Isolating EPDM Rubber Compounds to Enable Light-Weighting Solutions at Automotive OEMs

The automotive trend of replacing steel doors in cars with light-weight metals like Magnesium/Aluminum (Mg/Al) has a significant impact on the EPDM weather-strip (WS) requirements. To avoid electrochemical degradation of the EP DM WS and oxidation of metal surface, EPDM WS need to have 3-4 orders high er volume resistivity (VR) than standard WS. 

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