Dynamic Mechanical Characterization of Elastomers in Oil at Temperatures up to 200 °C

The fluid bath DMA 1 option allows the influence of swelling on the dynamic mechanical properties of a sample to be measured in the temperature range 0 to 200 °C. This means that deformation conditions of components that are in direct contact with fluids can be simulated (for example drive or timing belts that permanently run in motor oil).

Introduction

In recent years, the application areas of technical rubber materials have been greatly expanded through the optimization of important properties such as high temperature stability and resistance to media. An excellent example is that of drive belts in motors. A few years ago, drive belts could only be used at temperatures lower than 100 °C and where there was no contact with motor oil. Metal chains were therefore employed for critical parts instead of belts.

Nowadays, the lifetime of belts in permanent contact with hot oil is appreciably longer than that of the motor. In the development of such high-temperature and medium-resistant components, the characterization of the dynamic mechanical properties of materials in direct contact with media such as oils and fuels at high temperatures is of great importance.

This article describes a method that can be used to measure dynamic mechanical data of test samples in contact with a fluid in the temperature range –20 °C to 200 °C.

This includes information about swelling as well as the change in dynamic mechanical properties during swelling.

Samples and Properties

The elastomer used for the measurements was an EPDM material containing 52 weight percent ethylene and 4.3 weight percent ethylidene norbornene with a density of 860 kg/m3. For peroxide crosslinking, 2.4 phr di(tert-butylperox-yisopropyl)benzene was added. Curing was performed at 160 °C for 15 min. A 5W40 standard motor oil with a density of 850 kg/m3 was used for the swelling measurements.

Conclusions

The DMA 1 fluid bath option allows the dynamic mechanical properties of a sample in direct contact with a medium in the temperature range 0 to 200 °C to be determined.

As a consequence of this, the dynamic mechanical properties can be measured directly as a function of the swelling of the sample at different temperatures. On the one hand, this helps us to understand the chemical and physical processes that occur. Furthermore, the results can be used for the specific optimization of structure-property correlations of materials in direct contact with media.

_{Dynamic Mechanical Characterization of Elastomers in Oil at Temperatures up to 200 °C | Thermal Analysis Application No. UC 452 | Application published in METTLER TOLEDO Thermal Analysis UserCom 45}