Investigation of the effect of conductive fillers on the electrical conductive and strength properties of rubber

. A study was made of the conductive filler P-803 in a rubber composition based on butadiene methylstyrene rubber SKMS-30ARKM-15, which leads to an increase in electrical conductivity. Carbon black P-803, in addition to increasing the electrical conductivity of the material, improves the technical properties of the rubber composition


Introduction
Filler P-803 in a rubber composition based onbutadiene-α-methylstyrene rubberbased on SKMS-30ARKM-15 leads to an increase in electrical conductivity. Carbon black P-803, in addition to increasing the electrical conductivity of the material, improves the technological properties of the rubber composition. The specific electrical resistance was determined by a well-known method.
The physical and mechanical properties of rubbers based on a combination of SKD, SKI-3, SKS, SKMS-30 rubbers filled with different soot content were studied.

Materials and methods
Of all the studied sole rubbers based on a combination of butadiene rubbers -SKD, isoprene -SKI, butadiene-styrene -SRS, filled with various contents of electrically conductive fillers: acetylene and furnace black, graphite, metal powders, along with high wear resistance, have relatively low electrical resistance. The value of electrical resistivity, for the rubbers studied above, is significantly higher than the required level for conductive footwear. [1]. In order to improve the electrical conductive properties of rubber based on rubber SKMS-30 ARKM-15, we studied the effect of the dosage of conductive filler -technical carbon P-803 on the electrical conductivity of rubbers. The effect of acetylene black filler on the electrical conductive properties of rubber based on SKI-3 rubber was also studied. [2]. Depending on the polarity, the formulations of rubber compounds based on SKMS-30 ARKM-15 rubber are given. The composition of rubber based on SKI-3 is shown in Table 3 according to the standard method. Where  -specific electrical resistance, ohm cm; X -soot content, wt.h. The specific electrical resistance of rubbers based on SKMS-30 ARKM-15 and SKI-3 rubbers varies depending on the soot content according to the law of the third degree, only the value of the constant (in the numerator) is different and is determined by the nature of the rubber.
When changing the soot content in rubber based on these rubbers from 60 to 160 wt.h. the electrical resistivity value decreased from 14 to 0.6 Ohm cm (Fig. 1). The results of the experiment on the effect of the amount of fillers on the electrical conductivity of rubber. However, the electrical conductivity of rubber depends not only on the type of filler and its concentration, but also on many factors, for example, on the degree of dispersion, the chemical composition of the filler, the technological parameters for obtaining the composition, etc. The effect of conductive fillers on the strength characteristics of rubber (tensile strength) and relative elongation has been studied. Analyzing the results of the study, it should be noted that with an increase in the content of the filler -soot up to 60÷ 80 wt.h. rubber strength increases to a maximum value (Fig. 1) and then decreases, and the relative elongation increases (Fig.2). Significant filling of rubber compounds with soot leads to their high rigidity. The optimum filler content depends on the nature of the filler, the type of rubber and the composition of the rubber compound. [3].
Based on the nature of the dependences of the electrical conductivity of rubbers on the dosage of conductive fillers and the physical and mechanical properties of rubbers, a rubber composition based on methyl-styrene rubber SKMS-30 ARKM-15 with an optimal soot content P -803 was used for further research. 80 wt.h per 100 wt.h. rubber.   From the data in Table 4 it follows that the use of carbon black P-803 as a filler in a rubber composition based on rubber SKMS -30ARKM-15 leads to an increase in the electrical conductivity of rubber. At the same time, the physical and mechanical properties of rubber are also improved.
A comparative analysis of electrically conductive rubbers based on SKMS-30 ARKM-15 and SKI-30 was also carried out. Table 5. Comparative analysis of physical and mechanical properties of rubbers based on rubber SKMS-30ARKM-15 and SKI-3.

Rubber based on SKMS-30ARKM-15
Rubber based on SKI-3 A comprehensive assessment of electrically conductive rubbers based on SKMS-30 ARCM-15 and SKI-3 was also carried out.
The quality indicators of the properties of electrically conductive rubbers based on SKMS-30 ARKM-15 were compared with the basic method for constructing complex diagrams (Fig. 4). Its graphical interpretation showed that rubber based on SKMS-30 ARCM-15 exceeds the basic characteristics in terms of quality index, which indicates a higher level of electrical conductivity, as well as their performance properties. Next, a test was carried out on the effect of various accelerators on the electrical resistance of rubber. The vulcanization of rubber is one sulfur-very process and, therefore, the developed vulcanizates have high mechanical strength, which simultaneously with vulcanization, the processes of rubber oxidation proceed. [4]. Even with the time of discovery of vulcanization, experiments were made on the duration of this process, used in a mixture of various harmful effects -vulcanization accelerators.
Vulcanization accelerators are usually called chemical compounds that are introduced into a mixture of rubber with other ingredients to speed up the vulcanization process and improve the physical and mechanical properties of vulcanized rubber [5]. And therefore, in the work, the influence of various accelerators on the electrical resistance of vulcanizates was studied.  Table 6 shows the data on the electrical resistance of rubbers obtained using various accelerators. Table 6 shows that compositions with thiuram have reduced electrical resistance. It can be assumed that thiuram with rubber increases the possibility of the formation of electrically conductive carbon black chains and contributes to a better distribution of the ingredients in the mixture [6].
Rubbers encountered with the occurrence of thiuram, which are manifested by increased resistance to aging, the frequency of the tendency of rubber compounds to scorch, and having small residual deformations in compression [7].
However, the use of a thiuram accelerator in a rubber compound requires a vulcanization activator -zinc oxide. [8]. The oxide is highly cross-linked and thus improves the strength properties of the rubber.
The use of RTI crumbs increases at the end of the electrical conductivity of the rubber. This article has developed a formulation of electrically conductive rubber, which is presented in this table, which is part of the shoes for soles. Table 7. Components of the rubber composition. No.