The aim of the study was to determine the effect of accelerated thermal aging on the properties of selected poly(dimethylsiloxanes) (PDMS) differing in viscosity and hardness. This was related to the potential application for specialist casting molds with complex geometry. Four polyaddition silicones and two polycondensation ones were selected. As part of the work, tensile strength, hardness, density, roughness, and Dynamic Mechanical Analysis (DMA) and Fourier Transform Infrared Spectroscopy (FTIR) were tested, which allowed us to determine the degree of degradation of the analyzed materials subjected to thermal aging at a temperature of 150 ± 2 °C. The aging temperature was conditioned by the parameters of the materials that can be cast into molds made of poly(dimethylsiloxanes) e.g., with polymer resins, for which the exothermic peak ranges from 100 to 200 °C depending on the volume. It was observed that the initial Shore A hardness value affects parameters such as tensile strength or the amount of value change (its increase or decrease) after thermal aging. It can also be concluded that for polyaddition PDMS, the viscosity of the material has an effect on the size of the relative elongation value after thermal aging.

The paper presents a procedure of preparing, molding and testing polymer concrete containing 10 – 60% of bottom ash from power plant fluid circulating fluidized bed boiler (CFB)– the rest of the filler was a standard sand. The tests of static bending and mass changes after exposition to acid, base and salt were conducted. Also mass changes after freeze-thaw tests were registered. The tested polymer concretes showed no problems during manufacturing procedures. Compositions containing 10 - 20% by weight of the ash showed higher flexural strength than polymer concrete containing 100% sand and it was about 35 MPa. Relatively small changes in mass (less than 0.5% excluding base exposition for which it was less than 3%) caused by environmental factors, in general consistent with theoretical predictions, allow us to assume that the tested materials will meet the strength requirements for the footplates. It is studied in second part of the set. According to the environmental resistance and description of a whole designing and production process. It was found that the concrete containing 10%wt of the ash is optimal material for producing the plates. It has showed the best resistance to environmental aging from all tested concretes. The designed mold system is simple and reliable - it is applicable for serial production of the plates in industrial conditions. Visual quality of the produced plates was very good. In general, polymer concrete once again turned out to be very good material, applicable in various elements for construction industry.

In this article, we present an analysis of the properties of polyaddition poly(dimethylsiloxanes) (PDMS) and their potential applications after modification. The focus is on understanding how different fillers and mixing speeds affect the mechanical and electrical properties of PDMS, as well as the benefits and challenges associated with these modifications. Additionally, the prospects for future development of PDMS-based technologies, which could bring significant innovations in various industrial fields, are discussed.

This study investigated the influence of carbon fillers with different morphologies on the physicomechanical and electrical properties of composites based on polyaddition-cured poly(dimethylsiloxane) (PDMS). Conductive carbon black, flake graphite, and reduced graphene oxide (rGO) were introduced individually into the silicone matrix. In addition, selected multicomponent formulations containing conductive carbon black, flake graphite, and a viscosity modifier were prepared. The materials were characterized in terms of density, Shore A hardness, tensile properties, surface resistivity, microstructure, and thermal properties using differential scanning calorimetry (DSC). Conductive carbon black had the most pronounced effect on surface resistivity. At a filler content of 2.5 wt.%, the composite retained its insulating properties, whereas increasing the carbon black content to 5 wt.% reduced the mean surface resistivity to approximately 10⁶ Ω/sq, suggesting that the electrical percolation threshold likely lies between these concentrations. Within the investigated concentration ranges, flake graphite and rGO did not lead to the formation of effective conductive pathways. The incorporation of carbon fillers generally resulted in a reduction in tensile strength and elongation at break, with the most pronounced deterioration in mechanical properties observed for composites containing conductive carbon black. In contrast, flake graphite caused a clear increase in hardness with increasing filler content. DSC analysis showed that conductive carbon black had a strong effect on the enthalpy of the observed thermal transition, while only slightly affecting its characteristic temperature. The results confirm that the electrical and mechanical properties of PDMS composites are strongly determined by the morphology and content of carbon fillers, as well as by their mutual interactions.