Novosibirsk State Technical University has learned how to control the electrophysical properties of epoxy composites based on carbon nanofibers. Coatings made from the material obtained by scientists can be used in production to protect against static electricity.
High-energy ball grinding of carbon nanofiber material was used as one of the methods for controlling the electrophysical properties of epoxy composites. The crushed samples were used as a filler for epoxy composites.
"We used mechanical activation — in an energized mill, the material was ground in a very short time (up to 10 minutes). It became smaller, and by controlling the size of such particles, it became possible, firstly, to save carbon additives, and secondly, to control electrical conductivity," said Alexander Bannov, Professor of the Department of Chemistry and Chemical Technologies at NSTU-NETI, Doctor of Chemical Sciences.
The initial carbon nanofiber sample was subjected to ball grinding, varying the time from 2 to 12.5 minutes. The scientists found that carbon nanofibers shorten in various ways during the grinding process and that the electrical conductivity of the composites increased with increasing grinding time to 7.5 minutes, after which it began to decrease. High-energy grinding with an acceleration of 15 g and a grinding time of 7.5 min made it possible to obtain the highest values of electrical conductivity and permittivity of epoxy composites.
According to Alexander Bannov, the results of the study will make it possible to obtain composites with improved properties with less filler, which can be very useful for future applications. High-energy grinding of carbon nanofibers also improves the thermal characteristics of epoxy composites, making them more resistant to oxidation.
The resulting material can be used for anti-electrostatic coatings in industries where explosive environments require special safety measures (chemical, oil and gas, mining, metallurgical industries), as well as in warehouses where explosive substances or static-sensitive equipment are stored. In addition, epoxy composites are suitable for protection against electromagnetic interference and for monitoring the condition of structures.