Rheospectris: A New Instrument for Hyper-Frequency Viscoelastic Spectroscopy of Elastomers for R&D and QC

This paper aims to introduce a new analytical instrument for the viscoelastic spectroscopy of elastomers in the fields of research and development (R&D) and industrial quality control (QC). The instrument, called RheoSpectris^TM (Rheolution Inc., Montreal, QC, Canada), is based on a new patented technology and presents unique capabilities for dynamic mechanical testing of industrial materials. Indeed, RheoSpectris^TMmakes possible the measurement of material properties over an unexplored dynamic range (up to 2000 Hz), very rapidly (in less than 1 second), without contact (i.e. without damaging the sample) and over a wide temperature range. The instrument offers many sample holder geometries designed to allow the characterization of soft (~100 Pa) to very stiff (~500 GPa) materials.

Current commercial instruments like Dynamic Mechanical Thermal Analyzers (DMTA) and rheometers can measure the viscoelastic properties of polymers up to frequencies of 200 Hz (1000 Hz for very soft materials using shear geometries). The time-temperature superposition principle (TTS) is sometimes used when the material is thermorheologically simple to assess high frequency properties, but this predictive approach does not provide direct and reliable measurements. By giving access to high frequency material properties, RheoSpectris^TM opens new perspectives in terms of material performance improvement for dynamic applications. Indeed, the understanding of polymers behavior at high frequencies is of interest to control and improve the performances of elastomers intensively used in the tire industry, sealing technologies, vibration insulation, etc. In the case of tires, manufacturers pursue challenging technological objectives aiming at: attenuate the level of noise generated by the elastomer in driving conditions, reduce the vehicles energy consumption and formulate more performing and sustainable materials. Providing researchers and engineers of this industry with new instrumentation enabling the measurement of elastomer properties of at high frequencies will contribute to the achievement of these challenges. In addition, the rapidity of measurement of RheoSpectris^TMopens new possibilities to track and monitor rapid time-dependant behaviours like curing. The same characteristics also help to improve the testing productivity for real-time quality control of materials.

This paper first presents a comparison between measurements conducted on different elastomers using RheoSpectris^TM and classical rheometers and DMA instruments. The comparison between these different technologies is performed on their common frequency range. Original applications using RheoSpectris^TM are then presented: hyper-frequency characterization of elastomers, viscoelastic monitoring of rapid curing process, thermo-viscoelastic analysis of elastomers, and effects of fillers on the low and hyper-frequency properties of some elastomers.