MOSCOW, August 15 A new material to reduce the level of electromagnetic interference was created by UrFU scientists as part of an international research team. According to the authors, the development can significantly reduce the influence 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. This “insight” of the speakers is explained by electromagnetic interference, which is invisible to the eye and appears before the call itself passes.
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 against electromagnetic radiation, screens, usually metal, are installed on equipment. Experts attribute their disadvantages to heavy weight, low ability to resist corrosion, and difficulty in producing samples of unusual shapes. However, the biggest problem, according to scientists, lies in the way metal screens work: they reflect radiation rather than absorb it.
An alternative to metals is composite (consisting of several layers) materials based on polymers — long chains of identical fragments. The filler is chosen to be a substance that conducts current and, as a result, absorbs interference, and the role of the shell, on the contrary, is taken by dielectrics, so the radiation remains inside the composite, the experts emphasized.
UrFU researchers, together with scientists from the Laboratory of Structural-Chemical Modification of Polymers of the Institute of Technical Chemistry of the Ural Branch of the Russian Academy of Sciences and colleagues from Romania, have developed a new composite material capable of reducing the power of electromagnetic interference radiation by up to 10,000 times.
The university noted that the shell was made of ordinary industrial plastic, which is used in many electronic devices, and carbon and magnetic materials were the conductive fillers.
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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 materials, with some setups developed by members of the scientific team and 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.