Self-regulating electric heater based on elastomer, modified with multilayer carbon nanotubes

The review of modern approaches to the development of electric heating materials makes it possible to conclude that the studies of electrically conductive composites are based on using elastomers modified with nanoscale carbon materials. In the manufacturing of electric heaters, temperature self-regulation is the main property that increases their characteristics. However, researchers engaged in studying such heaters, face difficulties associated with the magnitude of supply voltage and power. In this regard, the tasks of the present work were as follows: to study the modifier characteristics for nanomodified heaters, and to select a modifier that is best dispersed in the elastomer, which will ensure the maximum magnitude of the supply voltage and the high value of the specific power of the heater. To develop an electric heater, silicone rubber modified with carbon nanotubes was used as an elastomer. The method for manufacturing the heating element nanomodified material was described. Multi-walled carbon nanotubes synthesized through the CVD method were employed as an electrically conductive modifier. Before modifying the elastomer, the carbon nanotubes were processed in a mill at a rotational speed of working blades of 25,000 rpm. Then, the nanotubes were thermally treated in a furnace until the temperature of 110 °C was reached. After that, the nanotubes and the elastomer were mixed using a BRABENDER mixer, followed by pressing and obtaining plates of the electric heating material. To ensure contact between the heater and the power source, aluminum foil, inserted into the punches before pressing, was used. The electrical conductivity of the elastic heater nanomodified material was studied using a setup (facility) constructed especially for that purpose. Based on the results obtained, a conclusion can be made on the expediency of using different multi-walled carbon nanotubes as elastomer modifiers, which form electrically conductive networks inside the elastomer and are capable of releasing heat when connected to an electrical voltage source. Employing a non-contact method of measuring the temperature field on the electric heater surface, thermograms were recorded. It was found that the temperature field is uniformly distributed on the heater surface and is stabilized at a certain time after achieving a thermal balance with the environment. From the data obtained, it can be concluded that the heating element connected to an alternating current network with a voltage of 220 V is efficient.