Understanding the Effects of In-Service Temperature and Functional Fluid on the Ageing of Silicone Rubber

Abstract

With an organic/inorganic hybrid nature, silicone elastomers are amongst the most versatile engineering materials, exploited in a wide range of applications either as end-products or in manufacturing processes. In many industrial machines, silicone components are exposed to in-service conditions, such as high or low temperatures, contact with functional fluids, mechanical loading, and deformations, which can adversely affect these components and reduce their lifespan, leading to machine failure in turn. The present study investigates the behaviour of a silicone component of a manufacturing equipment and the variations in the part’s properties due to in-service conditions (temperature, exposure to heat transfer fluid, and mechanical deformation) to develop a monitoring tool. An experimental design was employed to study the main and the interaction effects of temperature (22 °C, 180 °C), medium (air, synthetic heat transfer fluid), and strain (0%, 200%) on the silicone component’s properties. Results showed that while the chemistry of the component remains intact, its thermal and in particular mechanical properties are largely influenced by the in-service conditions. Consequently, leading to a physical rather than a chemical failure of the component and limiting its service life. Statistical analysis revealed that high temperature and the exposure to the heat transfer fluid have the most sever effects. Moreover, these two manufacturing parameters were found to have a significant interaction with one another, whose effect cannot not be neglected.

Thermal Aging Rheological Behavior of Magnetorheological Elastomers Based on Silicone Rubber

“…The obtained result was due to the changes of the molecular configuration accompanied by a hydro-thermal deterioration, which led to the development of microcracks of the matrix and the filler/matrix interface. However, a contradictory effect has been demonstrated in some studies [5,6], where the rubber composites exhibited a higher modulus of up to 215% in aged samples as compared to an unaged sample. Moreover, the maximum flexural stress was also increased by up to 15% and tended to decrease to almost 275% in comparison to the unaged sample.…”

“…The condition of exposure to these applications such as surrounding temperature, humidity, heat, and chemical attack will result in degradation with regard to time as well as aging issues. In general, the aging of the rubber composite is caused by chemical [5,6] and oxidative-destructive processes [7][8][9], thermal [10,11], heat, moisture, radiation [12,13], and also dynamical and mechanical strains. Among them, the two crucial factors negatively influencing the degradation or aging stability of rubber composites are temperature or heat, and the presence of an oxygen, which received from ambient condition or it is generated by their mechanical or dynamic strain test.…”

“…Moreover, numerous studies by other researchers [5,6,10,19] have concluded that, with the increased of temperature and aging time, the mechanical properties such as hardness, tear strength, and tensile strength would decrease as high as 72%. The obtained result was due to the changes of the molecular configuration accompanied by a hydro-thermal deterioration, which led to the development of microcracks of the matrix and the filler/matrix interface.…”

Loss Factor Behavior of Thermally Aged Magnetorheological Elastomers

“…Often, these types of mechanical vibrations can cause minor or severe performance and safety issues in engineering systems [4]. To date, polymer composites or elastomers have been broadly used in various applications such as automotive [5,6], machinery products, and even in aviation industry [7][8][9] due to their viscoelasticity in order to lessen the vibration. Magnetorheological elastomer (MRE) is one type of polymer composite that can potentially be used not only to reduce but to achieve the desired vibration or as adjustable damping materials.…”

Performance Degradation of Silicon Based Magnetorheological Elastomer Under Accelerated Weathering Treatment

“…However, on the other hand, engineered rubber products such as composites are very susceptible to the conditions of ambient temperature, humidity, heat, and chemicals that hit them. In general, the aging of rubber composites is caused by chemicals [5,6], thermal, heat [7,8], oxidative destructive [9][10][11], and moisture [12]. These conditions are conditions that depend on the weather.…”