A groundbreaking high strain rheometer that assesses the dynamic and static characteristics of raw rubber compounds and elastomers throughout the curing process. The RPA ultra is World’s top selling high strain and dynamic rheometer which was developed as part of a cooperation project ZiM (Zentrales Innovationsprogramm Mittelstand) between Bareiss and the Institute for Applied Polymer Chemistry at Aachen University of Applied Sciences.
Best Rheometer – Dynamic and High Strain
The Problem
In the version of the RPA used by Monsanto to date, only oscillatory tests with variable frequency and strain can be performed and thus usually used to determine the complex shear modulus and dynamic viscosity of a material. The classical approach of calculating both the storage modulus and the loss modulus with a simple trigonometric equation only applies to linear viscoelastic behavior.
Filled rubber compounds, however, show a strongly non-linear rheological behavior (Payne effect) and the measurement signal of unfilled raw rubber becomes nonlinear at higher deformations (LAOS). The issue of compound processability also cannot be quantified to date. As a solution-oriented company, Bareiss has addressed this problem as part of a cooperative project funded by the ZiM and has developed an RPA with extended testing capabilities.
The Future of Advanced Material Testing
At Bareiss our dedication to excellence drives us to offer only the highest quality material hardness testing instruments, always with a strong commitment to customer-focused solutions. As a premier manufacturer of high-performance test equipment, we are continuously broadening our product offerings and pioneering advancements with technology.
We are excited to introduce the RPA Ultra, an advanced Rubber Process Analyzer Rheometer a groundbreaking rubber testing instrument that transforms the way we examine material properties. This state-of-the-art rheometer is meticulously engineered to assess both dynamic and static characteristics of raw rubber compounds and elastomers throughout the curing process, delivering insights that were once beyond reach.
“Listening to customers, understanding problems and generating innovations from them is traditionally our strength.”
Oliver Wirth
Managing Director & Partner
Research and Development
The Solution – Dynamic Mechanical Rheological Tester
The RPA Ultra employs cutting-edge testing methodologies to extract a wealth of invaluable data from higher harmonics analysis, steady-state shear viscosity measurements, and the evaluation of non-elliptical Lissajous figures.
All RPA’s in the market are limited in strain (up to 360° of arc) and shear rate (up to 30 1/s). With the RPA Ultra from Bareiss Prüfgeratebau GmbH in Germany strain and shear rate moves in a completely new high level for material characterization. The RPA Ultra can be used to characterize polymers, mixtures and foods. The dynamic specifications are just as unique as the operational capability of the device.
The rotational lower die allows the transient viscosity of materials to be determined for the first time in areas that are highly relevant to production. Compared to dynamic viscosity, transient viscosity reflects the realistic processing of rubber compounds. The RPA ultra from Bareiss can certainly perform all test methods of a generic RPA, including isothermal and anisothermal tests, stress relaxation, frequency sweep and amplitude sweep.
Not only is it capable of performing oscillatory testing over a wider range of frequencies (10-3 Hz to 100 Hz) and strain range (unlimited strain LAOS), but also offers the possibility to perform a continuous shear rate in full rotation from 10-3 s-1 to 500 s-1, while standard RPA‘s can only measure up to a maximum of 30 s-1.
By embracing this unique and advanced approach to testing, we enhance the quality and reliability of our evaluations to unprecedented levels, effectively setting new benchmarks within the industry! With the RPA Ultra, our customers gain deeper insights and improved control over their material properties, fostering innovation and excellence in rubber processing.
Applications of Dynamic & High Strain Rheometer
This instrument thus expands the range of applications to better describe, among other things, current topics in rubber technology such as wall slip behavior, polymer branching and sustainable fillers (rCB). The number of data points recorded per cycle has increased significantly, which in turn improves the signal-to-noise ratio when performing Fourier Transform Rheology.
The ranges in which the device operates at shear rates of 500 s-1 are typical of the extrusion range. Initial studies have already shown that such a measurement method can be used to make an estimate of the processability of a compound. This means that in the event of substitution or fluctuations in raw material quality, the user can recognize at a very early stage whether this compound can be processed well or whether further processing aids need to be added, this also offers crucial time saving and financial advantages in the new development of rubber compounds.
“Bareiss’ RPA ultra is the first real major advancement in RPA’s since the 80’s”
Thomas Rauschmann
Consulting
RTS Rubber Technology and Service
For Further information and advise on rheology measurement methods and individual requirements, please don’t hesitate to contact us directly. We will be pleased to assist you to meet your material testing needs!
Partnership with Material Testing Specialists
Cooperation with Bareiss results in a whole range of valuable advantages for your company because you get the quality of an innovative manufacturer and the service of an accredited laboratory from a single source. In 1996, Bareiss was the first company in Germany to be accredited by DAkkS for mechanical measurands and is a great honor to our company Since then, Bareiss, as an accredited testing laboratory for the measurand hardness, has permanently performed laboratory and on-site calibration on all Durometer Type/Shore and IRHD instruments and issues official calibration certificates. In addition to the wide range of excellent hardness testers and the official calibrations Bareiss also offers a wide range of practical services and proudly serving Canada, USA, Mexico and all over the world!
„For many of our customers, we are not just a supplier, but a valued partner and consultant, on everything related to hardness testing – I am proud of that! “
Katrin Shen
Managing Director & Partner
Head of Sales and Marketing.
