Manufacturing Condition Effects on Mechanical and Tribological Properties of Filled Nitrile Butadiene Rubber

Nitrile Butadiene Rubber (NBR) seals are widely utilized in various industrial applications due to their excellent resistance to oils and fuels. In application, they often have to withstand high cyclical loads, which can lead to premature failure due to increased fatigue and friction. This may result in reduced service life, increased maintenance costs and potential operational failures, making it crucial to research and understand their mechanical and tribological behavior. The properties of NBR are influenced at various stages throughout the lifecycle of a rubber part. Starting from material composition, manufacturing process and application, environmental influences and ageing also significantly impact the material performance. The manufacturing process plays a crucial role, so this work focuses on how to achieve better performance and extend service life by adjusting manufacturing temperatures and -times. In this context, it is important to note that longer manufacturing times reduce the production capacity, which is undesirable in the industry. This thesis therefore also investigates whether shorter process times affect the properties of highly cured elastomers, e.g. after reaching the plateau of the reaction isotherms. For this purpose, test specimens made from silica- and carbon black-reinforced NBR were produced at different process temperatures and process times using compression molding, in order to achieve varying curing states. To examine the influence on the mechanical properties, tensile tests, fatigue tests, compression set tests and tear resistance tests were carried out. The tribological behavior was investigated using a ring-on-disc test setup on a tribometer. The aim of this work is to establish a correlation between the mechanical and tribological properties as well as the state of cure.