Experimental investigation of the dynamic mechanical behaviour of chemically aged elastomers

摘要

In recent years, the application of elastomer components has surprisingly increased in a large number of technical areas. Therefore, these materials have gained in significance in many fields of research. The possible applications of elastomer components range over a wide scale and naturally include areas as automotive, mechanical, plant, marine and civil engineering. Because of the characteristics of elastomers regarding ductility, processability, flexibility and adhesiveness, it is impossible to abstain from the application of this material. Although elastomers are used in different fields, only little basic research has been practiced in the area of ageing. Hence, it is necessary to conduct more research within this area in the future. Also relating to ageing behaviour, little experimental research on elastomers is known. From earlier research experiences with rubber, it is known that these materials can change their characteristics over time. These findings make intensive research activities on the long-term behaviour of elastomers indispensable. In the area of chemical ageing, detailed examinations are important since the molecular structure as well as the integrity of the material can alter. Based on these changes, different properties such as weight, tensile and flexural strength as well as the thermal and dynamic material properties can change. In order to be able to predict the lifetime of elastomer components such as automotive tires or suspension bushings, all environmental influences have to be explored intensely. In the area of chemical ageing, diverse experimental methods are necessary. Contemporary research work shows that the dynamic mechanical properties of chemically aged elastomers do not alter with increasing age. Currently, it is monitored whether these statements apply to all elastomers. The ageing behaviour of natural rubber is examined and evaluated in media such as air, sea water, distilled water, freshwater as well as different salt solutions. In this article, DMA, DSC and TMA tests are carried out to investigate the chemically aged specimens. Since ageing tests are very time-consuming, repetitions are not made. In the DMA tests, small strains are applied.