HEAT GENERATION OF NANOMODIFIED ELECTRICALLY-CONDUCTIVE POLYURETHANE DURING THE FLOW OF DIRECT CURRENT

The development of new types of functional materials based on modified polymers is a promising scientific task. Modified polymers are widely used in radio electronics and electrical engineering. The most effective approach that allows both to change physicomechanical and electro-physical properties of polymers is the introduction of carbon nanomaterials - nanomodifiers - into their structure. As there is a large variety of carbon nanostructures and the types of polymers, it is necessary to study and evaluate the influence of carbon nanostructures morphology and concentration of the introduced modifier on the properties of polymers. In this regard, the paper deals with the study of the influence of different morphology carbon nanostructures in the composition of polyurethane on heat generation during the flow of direct current. For this purpose, the authors carried out the experimental studies of polyurethane composites with different mass content (wt. %) of multi-wall carbon nanotubes (MWCNT) synthesized using different catalysts. The studies of electrically-conductive properties of nanomodified composites at different concentrations of two types of MWCNTs were carried out. During the study, the authors identified that PU modified with 7 wt. % MWCNT synthesized on Fe-Co/_2.1Al₂O₃ had the lowest specific volume electrical resistance (3.5×10⁴ Ω×cm). Using the non-contact method of measuring, the authors studied the distribution of temperature field on the surface of samples of nanomodified composites by connecting them to a DC source. It was found that heater samples made of polyurethanes modified with 7 wt. % MWCNT had the most uniform distribution of temperature field. The research revealed the effect of current fluctuations, which can be explained by the chaotic electrically-conductive network formed by an MWCNT in polyurethane. The study identified that different MWCNT mass content in the composite affects the temperature field distribution when a constant electric voltage is applied, which follows from special aspects of carbon nanostructures distribution in the polymer matrix.

polyurethane, specific volume resistance, composite, nanomodified polyurethane, multi-wall carbon nanotubes (MWCNT), temperature self-regulation