Study of the effect of technological clearances on electrophysical parameters of heated polymer materials

Among the reasons for the rejection of products made of polymer materials manufactured using HF electrothermy, an important place is occupied by the lack of available reference data on the modes of their processing. The inaccuracy of some electrical parameters, e.g., the dielectric loss tangent (tan δ ) and the dielectric constant (ε) are attributed to neglecting the effect of gaps in granular multicomponent polymer materials or technological system, as well as subjective factors of the control process. We present the results of studying the impact of gaps of a technological system on the electrophysical parameters of polymer and composite materials. We studied samples of granular materials «Bimodal polypropylene» and «Basco» stabilizing additive which are used in production of UV-resistant films for packaging. It is shown that a resonance method with the possibility of using two- and three-electrode system is most appropriate when determining the electrophysical parameters of polymer materials, their multicomponent mixtures and the optimal frequency of exposure. Refined (determined with allowance for gaps) electrophysical data for the materials under study obtained at a frequency of 27.12 MHz and heating to 120°C are presented. Comparison of the results obtained with and without taking into account the impact of gaps revealed that the difference reaches up to 12 (for tan δ ) and 9% (for ε) of their absolute value. Note that the parameter tan δ has the greatest effect on the heating efficiency. The optimal temperature of polymer heating at which tan δ reaches the maximum value is 50°C. The results obtained can be used to improve the quality of products produced from a wide range of multicomponent polymer and composite materials by optimizing the modes of their electrothermal processing.