Improving Heat Ageing, Mechanical Properties, and Thermal Conductivity of Silicon Rubber by Surface Modification of Iron Oxide and field testing of silicon rubber O-rings

Document Type : Research Paper


1 Nanotechnology Research Center, Research Institute of Petroleum Industry (Ripi), Iran

2 Advanced Polymer Materials and Processing Lab, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran

3 Research Institute of Petroleum Industry, Energy Division


Silicone rubber (SR) compounds were prepared for the application of O-ring at high temperature. Silane surface modified Fe2O3 and unmodified Fe2O3 were added to the SR compounds and the compounds were assessed by analyses of FESEM (for morphology) and TGA and tests of thermal conductivity at different temperatures, thermal aging, hardness, tensile and compression set. O-rings were prepared and field tested in an online Gas Chromatograph (GC) of Chemical Analysis in one Petrochemical Company, under pressure of 7bar and temperature of 180°C. The obtained results show that thermal conductivity, aging resistance, thermal stability and mechanical properties of SR decreased in the following order: surface modified Fe2O3 filled SR; unmodified Fe2O3 filled SR; SR without Fe2O3. Overuse of Fe2O3 reduced mechanical properties and hardened processability. Thermal conductivity of SR filled with varying volume percent of modified and unmodified Fe2O3 decreased as the temperature increased. The use of surface modified Fe2O3 resulted in increased thermal conductivity and improved aging resistance, ultimately leading to enhanced thermal resistance. This is particularly beneficial for the production of O-rings resistant to high temperatures. The field-test results confirmed that the O-rings were compatible with high temperature conditions. Furthermore, the O-rings exhibited low volume swelling and a smooth surface without any cracks, blisters, or unevenness after testing.