PSI - Issue 50

M.M. Kopyrin et al. / Procedia Structural Integrity 50 (2023) 137–146 M. M. Kopyrin et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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On the TMA graph, one can observe the dependence curves of the change in linear size as the temperature increases. For the SKD-V elastomer, the beginning of a change in the linear size of the sample is observed in the temperature range from -81.3 ° C to -75. 9° C, which is associated with the transition to a plastic state. These data correlate with the DSC indices (Fig. 9), where the glass transition temperature of the elastomer was - 79.4° C. After a temperature value of - 67.4° C, an almost linear change in the size of the elastomer is observed, which is associated with an increase in the mobility of rubber macromolecules. For composite materials, general trends in the behavior of TMA curves are observed. Therefore, for SKD-V BF, the transition to the elastic state occurs in the range of -87.6 ... - 80.1° C. The SKD-V GF composite goes into an elastic state in the range of - 89.5… - 81.9° C. For the sample SKD-V CF, the elasticity appears itself in the temperature range of - 92.4… - 85.7° C. The sharp drop in the TMA curves of reinforced elastomers after the values of these temperature indicators is due to the appearing of the elasticity of SKD-V (closer to the temperature range of the beginning and end of the glass transition) and the early inclusion of the mobility of the reinforcing fillers. At the same time, the temperature difference in the manifestation of elasticity of reinforced composites can depend on various factors that determine the technological deformability of the fabrics themselves: the use of different silane lubricants depending on the type of fabric, the difference in densities, types of weave of fabrics and the chemical composition of fillers. From the values of the TMA curves of the samples, the values of the coefficient of linear thermal expansion (CLTE) ᾱ were obtained. At the same time, the values of ᾱ were determined at temperature ranges from - 100 to 0° С - ᾱ 1, and from 0 to 100° С - ᾱ 2. The results of the CLTE values are shown in Table 2. Table 2 shows that the CLTE values at positive and negative temperatures for samples SKD-V BF and SKD-V GF are approximately at the same level. At negative temperatures, the CTE of the samples under the influence of the indenter decreases, and at positive temperatures, an increase in the CLTE is observed, which indicates an increase in the mobility of the samples. However, for the sample SKD-V CF, the values of the coefficients ᾱ 1 and ᾱ 2 have negative values: with an increase in temperature from - 100 to 0° C, a significant decrease in linear dimensions occurs under the influence of the indenter; in the temperature range from 0 to 100° C, relative stability of the CLTE of the material is observed. 4. Conclusion The results of the study of the physical and mechanical properties of reinforced elastomers suggest the following:  tensile strength of reinforced elastomers increased 1.7 to 2.8 times compared to the original elastomer, with maximum increase in strength being observed in the sample reinforced with basalt fabric and is 29 MPa;  relative elongation of the reinforced samples decreased significantly, 25-47 times compared to the elastomer without a reinforcing layer, the decrease occurs by;  weak adhesive interaction of BF, CF and GF with an elastomeric matrix was observed in the study of the microstructure and testing for adhesive characteristics. These results set the following goals and objectives for studying the increase in highly adhesive contact between frost-resistant elastomer and high-strength fillers;  the formation of a surface layer of BF, CF and GF on the rubber surface does not lead to an increase in wear resistance due to low adhesion of fibers with elastomer and the fragility of reinforcing fabrics;  from the DSC thermogram of a sample of the original SKD-V elastomer, the onset and endset temperatures of glass transition were established: -79.4 and - 84.7° C, respectively;  on the IR spectra of the samples, new peaks are not observed, the absorption bands characteristic of the original rubber and reinforcing fabrics are preserved;  the TMA plots show different temperature ranges after which mobility appears for each elastomeric composite. Table 2. CLTE data values for negative ( ᾱ 1) and positive ( ᾱ 2) temperatures. Materials ᾱ 1 , 10 -6 K ᾱ 2 , 10 -6 K SKD-V -16,45 37,06 SKD-V BF -456,15 285,95 SKD-V GF -551,90 281,28 SKD-V CF -1167,40 -8,77