The impact of gamma irradiation in the range of 500 to 2000 kGy on the toxicological profile of Carbomer 940 was evaluated. Irradiation at a dose of 500 kGy increased the toxicity of aqueous dispersions of the carbomer by 20
An approach based on a combination of micro- and nanosecond laser pulses for the analysis of steel samples through a scale layer is proposed. It has been demonstrated that using a combination of micro- and nanosecond pulses makes it possible to achieve linearity of the calibration curve, R2 = 0.964, which is comparable to the results of polished metal surface analysis. The proposed approach was successfully tested for quantitative elemental analysis under conditions simulating the motion of a steel sample, confirming its potential for real-time analytical monitoring in metallurgical production.
The effect of γ-irradiation in the dose range from 5 to 1700 kGy on the structural changes of the lightly crosslinked polyacrylic acid Carbomer 940 has been studied using IR spectroscopy to analyze the features of radiation-chemical transformations in the polymer matrix. It has been established that irradiation causes a stepwise change in the functional composition of the polymer, including redistribution of hydrogen bonds and rupture of crosslinks followed by modification of functional groups at high doses. At doses up to 400 kGy, a reformation of intermole cular interactions without degradation of the polymer backbone is observed. In the 400–800 kGy range, irreversible oxidative degradation occurs, forming anhydride structures. High doses lead to polymer carbonization. Characteristic spectral indicators of each step of radiation-induced transformations have been identified, including the appearance of new absorption bands and changes in the intensity of the existing ones. Importantly, the integrity of the polymer backbone is maintained even at maximum radiation doses, despite significant changes in its functional composition.
Experimental studies and analysis of the results of electrolyte-plasma treatment of copper, steel, and brass products using an electric discharge with weak and strong electrolytes were conducted. The samples were treated by immersing a metal anode (the product being treated) in a liquid (non-metallic) cathode. The surfaces of the metals were analyzed before and after treatment with various electrolyte solutions.
Changes in the thermal properties of carbomer after gamma irradiation have been analyzed using differential scanning calorimetry and thermogravimetric analysis. A multistep mechanism of thermal degradation of the polymer has been revealed upon heating in the range from 25 to 500°C. The most intense polymer degradation occurs at temperatures above 270°C. Thermogravimetric analysis revealed a shift in the peaks on the differential thermogravimetric curves, a decrease in their area, and an increase in the thermal degradation temperature, confirming an increase in post-irradiation thermal stability. It can be hypothesized that the increase in carbomer thermal stability under high radiation doses is associated with a decrease in the number of unsaturated bonds of pentaerythritol allyl ether that are not involved in primary crosslinking. The obtained data expand our understanding of the processes occurring in polyacrylates under the influence of ionizing radiation. This study has implications for the development of polymeric materials with controlled thermal and radiation properties.
