RESEARCH ON THE MECHANICAL PROPERTIES AND HEAT RESISTANCE OF PLASTICIZED EPOXY COMPOSITES WITH MICROADDITIONALS

Abstract

The article investigates the influence of microfillers on the mechanical and thermophysical properties of epoxy composites based on plasticized resin DER 331. As microfillers, chromium oxide Cr₂O₃ powders (20 μm) andsilicon carbide SiC (40 μm) were used with a content of 5 to 20 wt%. Mechanical properties were investigated: fracture stress and modulus of elasticity during bending, impact strength. Additionally, heat resistance tests of the developed materials were conducted.
Comparative analysis of the effect of microfillers confirms the advantage of using chromium oxide compared to silicon carbide for improving the properties of epoxy composites. At a concentration of 10 wt.% chromium oxide provides 6.4% higher strength of materials (85.2 MPa vs. 80.1 MPa) and 17.6% higher modulus of elasticity (4 GPa vs. 3.4 GPa) compared to composites filled with silicon carbide. This advantage is due to better adhesion to the matrix and the ability to form physical, covalent and ionic bonds at the interface.
The best results are characteristic of the material with chromium oxide, which at a content of 15 wt.% provides the formation of CM with values of tensile strength (88.3 MPa), elastic modulus (4.2 GPa) and heat resistance (364 K). The mechanism of improving the properties is that microdispersed particles form a structural framework that creates barriers to crack propagation (i.e., cohesive strengthening of the material occurs). For composites with Cr₂O₃, the formation of additional physicochemical bonds with the matrix is also key, which ensures the thermal stability of new materials.