Electrical conductivity of modified fabrics with carbon coating

Using the example of fabrics and knitwear from a mixture of natural and synthetic polymer fibers, the possibility of obtaining polymer compositions intended for the manufacture of electrically conductive elements for aviation, robotics and so-called "wearable electronics" for medical purposes is shown. The mechanical and electrical properties of fibrous compositions filled with carbon dispersions in various allotropic forms in combination with both soluble and insoluble high-molecular compounds in the form of powders or solutions have been studied. Dispersions of various forms of carbon with a close particle size distribution were selected from among commercially available brands of printing pigments and ingredients of rubber and electrical products. Carbon dispersions were investigated: graphite, carbon black and single-walled nanotubes in the form of a stabilized aqueous suspension. The well-known and justified optimal technological methods of introducing electrically conductive ingredients into the composition of composite materials, taking into account the structure and composition of fabrics. The advantage of spraying electrically conductive graphite particles on the surface of fibers and filaments in combination with the application of solutions and dispersions is shown, which makes it possible to obtain compositions for resistors and strain sensors with a sufficient level of strength and elasticity. The stretching diagram of the sensors and the dependence of the electrical resistance of the composition on the elongation with a high degree of confidence can be divided into two linear sections. The first section in the range of relative tensile strain from 2 to 30% is most consistent with practical application. The coefficient of sensitivity to deformation (GF) of a fabric-based strain gauge does not exceed 10 in the range of deformation in the diagonal direction up to 20%, and the coefficient of sensitivity to deformation on knitwear, regardless of the direction of cutting samples from the canvas, is two orders of magnitude higher and is about 950 to a relative elongation of 30% and 90 in the range of a relative elongation of 30÷45%. The maximum strain sensitivity (QF) of laboratory samples based on knitted fabric, with a deformation of less than 30%, is about 1350 kPa-1 and 4900 kPa-1 at maximum elongation%. The hysteresis of electrical properties with multiple deformations does not exceed 4%.