The Research of Physical and Mechanical, Thermophysical Properties of Epoxy-Polyester Composite Materials Filled with Discrete Fibers to Increase the Reliability of Vehicles

In the article the polymeric materials based on epoxy-polyester binder with addition of dispersed fibers were developed. The mechanical and thermophysical methods were used. The influence of carbon fibers (0.01–0.30 pts.wt.) and cotton (0.01–0.30 pts.wt.) on the physical and mechanical, thermophysical properties of epoxy-polyester composites was investigated. The results of the experiment showed that the introduction of carbon fibers leads to an increase in the fracture stresses, the flexural modulus; the maximum increase was observed for the carbon fiber content q = 0.01 pts.wt. (fl = 71.0 MPa, E = 3.8 GPa, W = 7.8 kJ/m2 ). The heat resistance of composite materials at this content of carbon fibers is maximal (T = 337 K), and the coefficient of linear thermal expansion (CLTE) is minimal and decreases in all temperature ranges (compared to the matrix). It was found, that the introduction of cotton fibers at a content q = 0.02 pts.wt. into the composition leads to an increase of the flexural modulus from E = 3.6 GPa (matrix) to E = 3.8 GPa and flexural stresses from fl = 50.4 MPa to fl = 55.2 MPa. The impact strength of such materials decreases from W = 8.3 kJ/m2 to W = 4.9 kJ/m2 . The results of the study of physical and mechanical properties of composite materials with the addition of cotton fibers were confirmed by thermophysical properties. It was found, that the heat resistance of materials increases from T = 335 K to T = 338 K at this content. The developed composite materials filled can be used to protect equipment, which are exposed to high temperatures or dynamic loads at moderate temperatures.