ANALYSIS OF THE THERMAL STABILITY AND SURFACE AREA OF ANTIPYRENES SYNTHESIZED FOR TEXTILE MATERIALS

ABSTRACT

This work explored the stability of natural textile materials, modified with antipyrenes as well as antipyrenes, using a cross-comparison of thermal stability of natural textile materials. In addition scanned microscopy and Element Analysis of the surface surfaces of modified textile meterials were researched.The effective kinetic parameters for the thermal degradation of stabilized samples were calculated from thermogravimetric analysis (TGA) data using the Freeman and Carroll method.  (The temperature range for the analysis was set at 100-1000°C) and scanning electron microscope (The composition of these modified polymers depends on their uniform distribution using the electron microscope of Japan JSM-6460LA. It is a firm of Jeol Interactive Corporation and it has the following specifications: permissible: 4.0 Nm (at 30 KV voltage: 0.1 to 4.9 KV (with 10 v step voltage), 5 to 30 KV voltage (100 V); gain: x8 to X 300,000) studied.

АННОТАЦИЯ

В этой работе изучалась стабильность натуральных текстильных материалов, модифицированных антипиренами, а также антипиреновых добавок, с использованием перекрестного сравнения термостойкости натуральных текстильных материалов. Кроме того, были проведены исследования с помощью сканирующей микроскопии и элементного анализа поверхности модифицированных текстильных материалов.Эффективные кинетические параметры термической деструкции стабилизированных образцов были рассчитаны по данным термогравиметрического анализа (ТГА) с использованием метода Фримена и Кэрролла.  (Температурный диапазон для анализа был установлен на уровне 100-1000°C) и сканирующий электронный микроскоп (состав этих модифицированных полимеров зависит от их равномерного распределения) с использованием электронного микроскопа японского производства JSM-6460LA. Он разработан компанией Jeol Interactive Corporation и имеет следующие технические характеристики: допустимый уровень: 4,0 Нм (при напряжении 30 КВ: от 0,1 до 4,9 КВ (с шагом напряжения 10 В), от 5 до 30 КВ (100 В); коэффициент усиления: от 8 до 300 000).

Keywords: antipyrenes, thermal analysis, TGA, DTA, derivatogram.

Ключевые слова: антипирены, термический анализ, ТГА, ДТА, дериватограмма.

Introduction. Ensuring fire safety remains one of the pressing issues through widespread use in the production of clothing, upholstered furniture, mechanical engineering, construction, the production of special clothes, building decor and other industries based on Fireproof natural textile materials. Therefore, the creation of textile materials and light industrial products with a fire-resistant property is one of the current topics of today. Therefore, great attention is paid to the development of oligomeric antipyres containing metals, phosphorus and nitrogen, as well as the creation of their optimal compositions and the improvement of the mechanism of Action [1; 2; 6; 8].

Materials and methods: Synthesis of Phosphorus- and Nitrogen-Containing Flame Retardants:

Antipyrenes containing phosphorus and nitrogen were synthesized. Orthophosphoric acid (85%, 23.05 g, 0.2 mol), zinc oxide (3 g), and urea (24 g, 0.4 mol) were placed in a container equipped with a temperature controller, reflux condenser, and mechanical stirrer. The reaction was carried out for one hour, maintaining the flask temperature between 90–100°C. This process yielded a white, fluffy product with a 90% yield. The thermal stability of the resulting antipyrenes and textile materials modified with them was analyzed using thermogravimetric analysis (TGA) [5; 7].

Methods. The analysis of the synthesized compounds was performed using the differential thermogravimetric method, employing a derivatograph operating within the Paulik-F, Paulik-I, and Erdey-L system. This method evaluates thermal effects of compounds over a temperature range of 293–793 K, with a heating rate of 2–5 K/min.

The effective kinetic parameters for the thermal degradation of stabilized samples were calculated from thermogravimetric analysis (TGA) data using the Freeman and Carroll method.  (The temperature range for the analysis was set at 100-1000°C) and scanning electron microscope (The composition of these modified polymers depends on their uniform distribution using the electron microscope of Japan JSM-6460LA. It is a firm of Jeol Interactive Corporation and it has the following specifications: permissible: 4.0 Nm (at 30 KV voltage: 0.1 to 4.9 KV (with 10 v step voltage), 5 to 30 KV voltage (100 V); gain: x8 to X 300,000) studied.

Results and Discussion:

In the initial thermal analysis, mass loss in the temperature range of 50–600°C was examined for the synthesized oligomeric antipyrene formed from the interaction of orthophosphoric acid, urea, and zinc oxide [7, 8]. Figure 3.1 illustrates a mass loss of 0.05 mg due to water evaporation in an antipyrene sample of 3 mg at 100°C in TGA conditions. Based on TGA results, a mass loss of 0.10 mg occurred between 100–200°C, while a 0.20 mg loss was observed between 200–300°C. Additionally, a mass loss of 0.66 mg was recorded in the range of 300–450°C. Between 450 and 543°C, 50% of the total sample mass decomposed, with 1.5 mg decomposed from the initial 3 mg.

Figure 3.1 in the DTA analysis shows red lines representing the samples, which exhibit primarily three endothermic processes involving heat absorption. These endothermic processes occur within the temperature range of 238°C to 323–378°C. Experimental thermal analysis has demonstrated that the synthesized antipyrenes possess higher thermal stability compared to untreated textile materials and those treated with antipyrenes.

Figure 1. Derivatogram of antipyrene

Based on experimental data on the kinetics of processes within the temperature range of 50–600°C, the thermo-oxidative degradation properties of the antipyrene were studied. The thermal decomposition of textile materials was analyzed using thermogravimetric (TGA) and differential thermal analysis (DTA) curves. In TGA analysis, the mass loss of a 2.42 mg sample was studied, showing the emission of water vapor at 100°C. In the range of 100–200°C, thermal decomposition occurred within the textile material’s structure, resulting in a mass loss of 0.21 mg (8.7%). The 200–280°C range showed the highest thermal decomposition, with a mass loss of 1 mg, corresponding to a 50% reduction in total mass. During the charring phase, 0.9 mg was lost between 280–400°C, and in the 400–600°C range, 0.1 mg was lost, producing coke residue of approximately 0.2–0.3 mg. DTA analysis indicated a single endothermic peak at 292°C due to heat absorption [4].

Figure 2. Derivatogram of textile material (TM)

Based on experimental data on process kinetics within the temperature range of 50–600°C, the thermo-oxidative degradation properties of the antipyrene were investigated.

Derivotogram of a sample of antipyrene suspended fabric

A derivatogram of an antipyrene-treated fabric sample is provided in Figure 3, displaying two curves.

Figure 3. Derivatogram of a sample of Antipyrene coated fabric

Thermogravimetric analysis (TGA) shows that the TGA curve reflects an intensive decomposition within specific temperature ranges: 26.99–140.56°C, 140.56–317.51°C, and 317.51–601.3°C, as shown in Figure 3.3. The results indicate that within the 140.56–317.51°C range, a significant decomposition process occurs, with a mass loss of 41.034% relative to the total mass. In the DTA analysis, three endothermic peaks were identified, indicating heat absorption at temperatures of 161°C and 251–285°C. Based on the TGA and DTA analysis results, kinetic parameters were calculated for different temperature ranges, allowing for kinetic characterization across the full reaction temperature range from a single sample.

The mass loss rate (VM) was determined by graphically differentiating the TGA curve using the formula:

VM=DM/VM

where DM represents mass loss in mg, and DT is the time interval in minutes.

A detailed analysis of the TGA and DTA curves is provided in Table 1 below.

Table 1.

The effect of temperature on weight loss of antipyrene-soaked fabric

The activation energy values of this process are indicated for the antipyrene suspended fabric sample. (Table 2).

Table 2.

Results of Thermal-oxidation analysis of a sample of FM-branded antipyrene coated fabric

The derivatographic studies show that the primary mass loss occurs in the temperature range of 26.99–140.56°C during the first decay phase, with 5.758% of the initial mass lost. The second decay phase occurs between 140.56–382.51°C, where 44.034% of the mass is lost. The third decay phase occurs between 317.51–601.3°C, with 19.702% of the mass lost.

Based on experimental data on the kinetics of processes in the temperature range from 293 to 943 K, the thermo-oxidative degradation properties of the FM-branded antipyrene-treated fabric were studied.

Microscopic analysis, electron microscopy, and elemental analysis were used to study the modification of antipyrenes in fireproof materials. These materials were obtained by processing natural textile fibers with the proposed modifiers. The incorporation of synthesized antipyrenes into textile materials (at concentrations of 5-20%) resulted in the formation of structures with enhanced fire resistance. The arrangement of these structures was investigated, as shown in Figure 4.

Special attention in the analysis of the experimental test results is drawn to the modification of cellulose-based natural textile materials with phosphorus, nitrogen, and metal-containing antipyrenes. It was found that the modification process occurred partly due to the interaction of hydroxyl groups with the phosphorus and nitrogen bonds.

Figure 4. A general mechanism for the modification of natural textile materials with antipyrenes

The distribution of the proposed modifiers on the surface of natural textile materials was considered separately. The morphological structure was investigated through microscopic analysis of the flame-retardant composite materials (Figures 5-6) obtained by modifying natural textile materials with synthesized antipyrenes. Composite materials modified with antipyrenes are shown in Figure 5 (1; 2; 3; 4), and as depicted in Figure 6, it can be observed that the antipyrenes containing phosphorus, nitrogen, and metal are uniformly distributed on the surface of the fibers. These modifiers range in size from 250 µm to 10 µm and are present in the form of white granules.

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Figure 5. Microscope analysis of modifiers

Figure 6: Scanning Electron Microscope (SEM) Analysis of Modifiers

Scanning electron microscope analysis of the cross-sections of modifiers with sizes ranging from 250 µm to 100 µm reveals an even layer between the fibers of the modified natural textile materials. This layer contributes to the improvement of the material’s mechanical properties. Additionally, elemental analysis was performed to identify the chemical components of the modified natural textile materials. The analysis shows the presence of nitrogen, phosphorus, metals, as well as carbon, oxygen, and cellulose-associated antipyrene compounds [4] (Figure 7).

Figure 7: Elemental Analysis of Modifiers

Conclusion. Oligomeric antipyrene-treated textile materials containing phosphorus were studied to determine their thermal stability and flame retardant properties. The research shows that the decrease in the degradation rate of cellulose in textile materials between 150°C and 350°C positively affects the increase in cellulose dehydration reactions. SEM analysis of the composites formed from textile materials treated with new types of oligomeric antipyrenes reveals that the antipyrene molecules were uniformly dispersed on the surface of fabric samples treated with the antipyrene solution. Furthermore, when treated with a new type of environmentally friendly antipyrene solution, it was found that both the fabric properties and its fire-resistant properties were significantly improved.

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