The aim of this paper is to study the effect of a polyfunctional modifier oligo (resorcinol phenyl phosphate) with terminal phenyl groups and a dispersed mineral filler, diorite, on the physicochemical and deformation-strength properties of epoxy-based composites. The efficiency of using diorite as an active filler of an epoxy polymer, ensuring an increase in strength and a change in the physicochemical properties of epoxy composites, has been proven. We selected the optimal content of diorite both as a structuring additive and as a filler in the composition of the epoxy composite (0.1 and 50 parts by mass), at which diorite reinforces the epoxy composite. It has been found that the addition of diorite into the epoxy composite results in an increase in the Vicat heat resistance from 132 to 140–188 °C and increases the thermal stability of the epoxy composite, which is observed in a shift of the initial destruction temperature to higher temperatures. Furthermore, during the thermal destruction of the composite, the yield of carbonized structures increases (from 54 to 70–77% of the mass), preventing the release of volatile pyrolysis products into the gas phase, which leads to a decrease in the flammability of the epoxy composite. The efficiency of the functionalization of the diorite surface with APTES has been proven, which ensures chemical interaction at the polymer matrix/filler interface and also prevents the aggregation of diorite particles, which, in general, provides an increase in the strength characteristics of epoxy-based composite materials by 10–48%.

This article describes the preparation of aluminum nitride (AlN) functionalized with amino groups by chemically modifying the surface of AlN with aminoacetic acid and their dispersion in the epoxy composition. As a result of the studies, it was found that the functionalization of AlN particles with aminoacetic acid ensured their better chemical compatibility with the epoxy composition, which facilitated the dispersibility of AlN particles; it was also found that the functionalization of the nanofiller has a significant effect on the structure, curing kinetics, physicochemical and mechanical properties of epoxy nanocomposites. The optimal concentration of the functionalizing agent (aminoacetic acid) has been determined, which is necessary for the chemical binding of the functional groups of aminoacetic acid, the epoxy oligomer and AlN, which best affects the dispersion and the size distribution of AlN particles, and also ensures maximum strength characteristics of epoxy composites containing AlN treated with aminoacetic acid: bending stress and bending modulus increase by 35% and 80%, respectively, while tensile strength and tensile elastic modulus increase by 74% and 36%, respectively. Furthermore, the impact strength shows a remarkable boost of 133% compared to plasticized epoxy composite without AlN.

The influence of basalt filler on mechanical properties of polyethylene (PE)- and polypropylene (PP)-based composites, and the effect of basalt on heat resistance and inflammability of polymer composite materials were studied. The introduction of basalt into the composite increases its elasticity modulus. The best mechanical properties are observed when 40 parts by weight of basalt per 100 parts of low-density PE and high-density PE are introduced. At the same time, a slight decrease in the deformation at failure is observed in basalt-filled PE composites. Deformation before failure is reduced from 380% for original PE to 250% for the composite containing 40 mass of basalt per 100 parts of PE. In the case of PP, this tendency is not observed. Other mechanical characteristics of polymer composites slightly change with the introduction of basalt particles as a filler. Incorporating basalt into PE and PP influences the combustibility of composites: oxygen index increases 1.3 times compared with the unfilled polymers, self-burning time decreases more than 2 times, and the loss of mass during ignition in the air decreases 2.15 times for PE-based composite and 1.75 times for PP-based composite. All indicators of flammability vary additively to the content of basalt, which is a noncombustible material.

This paper presents a study on the prospects of functionalizing nanodiamonds (NDs) with aminoacetic acid to obtain high-strength composites based on an epoxy matrix. The impact of the functionalization of the ND surface with aminoacetic acid in various concentrations on the properties of the epoxy composite was assessed. The success of grafting amine onto the ND surface was confirmed by X-ray phase analysis and IR spectroscopy. The results show a significant decrease in the average size of ND particles, from 400 nm for the pristine ones to 35 nm, and the contact angle, from 27° to 22°, with an increase in the specific surface area after treatment with a 5% solution of aminoacetic acid. Reducing the average size of NDs allows them to be better distributed throughout the epoxy matrix, which, as a result of the formation of chemical interaction at the matrix–nanofiller phase interface, can significantly increase the strength of the obtained composite. The addition of NDs treated with aminoacetic acid ensures an increase in the deformation-strength properties of epoxy composites by 19–23% relative to an epoxy composite containing the pristine NDs. Moreover, the presence of functionalized NDs significantly influences the structure and thermal stability of the epoxy nanocomposite.

Dispersed fillers (basalt, chromite) are modified in an induction installation at a power of 2 kW and a processing time of 60 s, which ensures a short-term high-temperature effect of high-frequency (HF) currents on the fillers and, as a result, improves the characteristics of the filled epoxy compounds based on them. The chemical composition of the fillers is found to change, which is associated with the removal of unbound moisture, an oxide film, and the oxides of the substances the decomposition temperature is lower than the modification temperature from the surface of basalt and chromite particles. Electron microscopy data demonstrate that basalt particles acquire a needle-like shape after exposure to HF currents, which positively affects the physicomechanical characteristics, since such a filler exerts a micro-reinforcement effect. Chromite particles weakly change their structure after HF current treatment. The study of the dielectric characteristics of the mineral fillers before and after HF current treatment shows that the dielectric constant increases significantly for basalt and chromite, indicating a change in their structure; this increases the strength characteristics from 7 to 17%.