MOSCOW, August 15 A new material for reducing electromagnetic interference was created by UrFU scientists as part of an international research team. According to the authors, the development allows for a significant reduction in the impact of electromagnetic radiation on equipment. The results are presented in the journal Polymers.
When the first mobile phones appeared, an incoming call could be predicted by the characteristic hum in the music speakers. Such «insight» of the speakers is explained by electromagnetic interference that is invisible to the eye and appears before the call itself is made.
However, it is not only artificial sources like cellular networks that cause interference. Lightning, the Earth's magnetic fields, or cosmic noise can also be the cause. In any case, interference disrupts the normal operation of electrical devices, so reducing its level is an important task, according to the Ural Federal University named after the first President of Russia B.N. Yeltsin (UrFU).
To protect equipment from electromagnetic radiation, screens are installed, usually metal ones. Experts consider their disadvantages to be heavy weight, low ability to resist corrosion and difficulty in manufacturing samples of unusual shape. However, the biggest problem, according to scientists, is hidden in the mechanism of operation of metal screens: they reflect radiation, but do not absorb it.
An alternative to metals is composite (consisting of several layers) materials based on polymers — long chains of identical fragments. Substances that conduct current and, as a result, absorb interference are chosen as a filler; on the contrary, dielectrics are used as a shell, so the radiation remains inside the composite, experts emphasized.
UrFU researchers, together with scientists from the Laboratory of Structural Chemical Modification of Polymers at the Institute of Technical Chemistry, Ural Branch of the Russian Academy of Sciences, and colleagues from Romania, have developed a new composite material capable of reducing the power of interfering electromagnetic radiation by up to 10,000 times.
The university noted that the shell was ordinary industrial plastic, which is used in many electronic devices, and the conductive fillers were carbon and magnetic materials.
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«We chose magnetite (a type of iron oxide) and carbon fibers 3-5 mm long as fillers. The introduction of both components into ABS plastic increases the electrical conductivity of the material many times over, but worsens its thermal stability,» said Viktor Chechetkin, one of the study's authors, a leading engineer and senior lecturer at UrFU.
He added that to improve the composite's ability to retain its properties at elevated temperatures, the scientists selected the optimal volume of filler (2.5% by weight).
«A variety of setups were used to study both the physical, mechanical and electrodynamic properties of the materials, with some setups being developed by members of the research team and not have no analogues in Russia,” Chechetkin emphasized.
Today, the research team is faced with the task of developing a technology for the industrial production of composite material.
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