Researchers at IPMash RAS developed a new approach to studying polymer friction and wear, which can be applied to analyze wear resistance at the molecular level of a wide range of polymer materials and their nanocomposites. The results of the study were published in a number of scientific journals «Friction and wear», «Problems of mechanical engineering and reliability of machines», «Issues of Materials Science», «Bulletin of Mechanical Engineering». Polymer materials are used widely in modern engineering, especially in friction units, where they can replace non-ferrous alloy parts effectively. Polymers have several advantages: they are lightweight, vibration-resistant, have a low coefficient of friction when paired with steel, and are able to work without lubrication, in aggressive environments, and even in extreme conditions such as the Far North or outer space. Replacing traditional materials with polymers saves resources and simplifies technological processes. However, in their pure form, polymers are inferior to metals in terms of physical and mechanical characteristics. To improve their strength properties and expand the load range, various fillers, including nanoscale ones, are added to polymers. This makes it possible to create composites with specified properties suitable for specific operating conditions. The main problem is that the mechanisms of friction and wear of polymer composites are not understood fully. The size of filler nanoparticles can be comparable to the size of polymer matrix molecules, which makes the process of their interaction complex and multifaceted. Traditional research is often limited to studying surface fracture at the macro and meso levels, whereas wear is the result of multiple processes occurring at the molecular and supramolecular levels.

To solve this problem, the scientists of the Institute of Problems in Mechanical Engineering of the Russian Academy of Sciences (IPMash RAS) developed an innovative approach based on molecular dynamics methods. They modeled the friction and wear of molecular models of polymers and their nanocomposites. As a result of the research, it was found that addition of the filler leads to an increase in the energy characteristics of the intermolecular interaction, that stabilizes the kinetic state of the composite molecules compared with the initial polymer.

“Based on the conducted research, we developed a criterion for assessing the wear resistance of polymer composite materials — the value of the energy of intermolecular interaction. This parameter allows us to predict the wear resistance of materials at the micro level, taking into account the influence of nanofillers on the structure and energy properties of the composite," said Elena Sedakova, a leading researcher at the Laboratory of Friction and Wear at IPMash RAS.

In addition, a connection was found between the type of the nanofiller and the energy of intermolecular interaction. This discovery formed the basis of an original technique for predicting the wear resistance of polymer composites, which can be used for the targeted development of materials for specific operating conditions. Thus, the development of IPMash RAS scientists makes it possible not only to understand better the mechanisms of friction and wear of polymer composites, but also to create materials with specified properties, that opens up new opportunities for their use in mechanical engineering.