STUDY OF THE DESTRUCTION OF IONITE OBTAINED ON THE BASIS OF THIOCARBAMIDE FORMALDEHYDE RESIN BY THERMAL ANALYSIS

ABSTRACT

This article presents the results of a thermal analysis of ionite synthesized on the basis of urea-formaldehyde resin. The process of mass loss was studied using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The changes in the physical properties of polymeric materials under the influence of various factors were explained. The findings demonstrate that the main mass loss occurs between 200–400 °C, accounting for about 73.7% of the total weight, while the material remains relatively stable at 600 °C.

АННОТАЦИЯ

В данной статье представлены результаты термического анализа ионита, синтезированного на основе карбамидоформальдегидной смолы. Процесс потери массы исследован методами термогравиметрического (ТГА) и дифференциально-термического (ДТА) анализа. Объяснены изменения физических свойств полимерных материалов под воздействием различных факторов. Результаты показывают, что основная потеря массы происходит в диапазоне температур 200–400 °C, составляя около 73,7% от общей массы, при этом материал сохраняет относительную стабильность при температуре 600 °C.

Keywords: destruction, polymers, thermogravimetric analysis, differential thermal analysis, ion exchange resin, mass loss.

Ключевые слова: деструкция, полимеры, термогравиметрический анализ, дифференциальный термический анализ, ионообменная смола, потеря массы.

Introduction

Polymeric materials are subject to various physical and chemical influences during synthesis and application, such as heat, light, and reactive environments. These factors can initiate the destruction of macromolecules, leading to reduced molecular weight, changes in mechanical strength, and alteration of physicochemical properties. The process of destruction is therefore a critical factor in determining the performance of polymers.

The main purpose of this study is to investigate the thermal destruction process of an ion-exchange resin based on thiocarbamide–formaldehyde resin using TGA and DTA, to determine its degradation stages, and to compare the results with known literature data on polymer stability [1][5].

Materials and methods

Thermogravimetric analysis is a method of measuring the change in weight (mass) of a substance as a function of time or temperature when it is heated or heated to a certain temperature. This change in weight can be due to various reasons. One of these is the evaporation or loss of moisture (water) or other residual solvents, which takes a certain amount of time. Thermogravimetric analysis and Differential Thermal Analysis are used together, and while one measures the mass change, Differential Thermal Analysis measures the temperature difference, that is, the heat effect of the process. When used together, it determines at what temperature the substance loses mass and whether the process is exothermic or endothermic. The graph shows two curves. One is purple and the other is red. The purple line is the TGA curve, which shows the mass change under the influence of temperature, while the red curve corresponds to the DTA, which shows the change in the heat effect of the process. Urea reacts with formaldehyde in weakly acidic, neutral and weakly basic media to form crystalline methylol derivatives analogous to methylol urea [3]. The process began with the preparation of dimethyl urea in a three-necked round-bottomed flask equipped with an automatic stirrer, reflux condenser and thermometer. To this end, 7.6 g (0.1 mol) of urea was added to 15.8 ml (0.2 mol) of formalin solution and stirred at about 40°C. 5-6 drops of 4% NaOH solution were added to the mixture (pH= 11.5). The mixture was heated slowly and 12.8 g (0.05 mol) of melamine was added to it with stirring. The temperature was gradually increased to 80-95°C, and stirring was stopped when a solid resinous resin was formed. Then the resulting resin was placed in a porcelain cup and washed 5 times in distilled water; After grinding in a porcelain mortar, it was washed 4 more times, first in dry air and then in a drying oven at a temperature of 40℃. The dried sorbent was red granular and insoluble in water.

Various analytical methods were used on the obtained new ionite and the corresponding results were obtained. Among them, its resistance to a certain temperature was analyzed by the thermal method [2][3].

Thermal destruction was studied using a Netzsch STA 449 F3 Jupiter instrument (Germany). Samples (10–15 mg) were placed in aluminum oxide crucibles and analyzed in a nitrogen atmosphere (50 mL/min) with a heating rate of 10 °C/min over the range of 30–600 °C. Mass loss was recorded with ±0.001 mg accuracy. Experiments were repeated three times. Data processing was carried out using Proteus software [4].

Results and discussion

In this analysis, the temperature of the TGA curve was between 0 and 600℃, and the mass loss during the process was -7.00 mg. In this case, the main mass loss was observed in the range of 200-400℃, with a large mass loss. The tested sample was due to hygroscopic water release, and the total mass loss was 73.7%. At 600℃, the polymer ion exchanger softened and changed its properties very little.

Table 1.

Thermogravimetric data of the resin

Figure 1. TGA curve of thiocarbamide–formaldehyde ion-exchange resin (0–600 °C)

Thermogravimetric analysis and Differential Thermal Analysis are used together, and while one measures mass change, Differential Thermal Analysis measures the temperature difference, i.e. the heat effect of the process. When used together, it determines at what temperature a substance loses mass and whether the process is exothermic or endothermic. The graph shows two curves. One is purple and the other is red. The purple curve is the TGA curve, which measures mass change with temperature, while the red curve is the DTA curve, which measures the heat effect of the process.

Conclusion

The thermal destruction of thiocarbamide–formaldehyde resin proceeds in multiple stages involving dehydration, polymer chain decomposition, and final degradation of carbonaceous residues. The study highlights the relationship between thermal conditions and polymer stability. Compared to literature data, the synthesized resin demonstrates typical but slightly shifted degradation patterns, suggesting a degree of improved thermal stability. Controlling such processes is crucial for designing polymeric materials with optimized physicochemical properties.

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