rus
Issue #7-8/2023
A.V.Blinov, Z.A.Rekhman, A.A.Gvozdenko, A.B.Golik, I.M.Shevchenko, M.A.Yasnaya, P.G.Sinyugina
SYNTHESIS AND STABILIZATION OF NANO-SIZED CALCIUM CARBONATE WITH METHYL CELLULOSE
SYNTHESIS AND STABILIZATION OF NANO-SIZED CALCIUM CARBONATE WITH METHYL CELLULOSE
DOI: https://doi.org/10.22184/1993-8578.2023.16.7-8.408.415
This work presents a method for the synthesis of calcium carbonate nanoparticles stabilized by methylcellulose. Calcium acetate was used as a precursor, and ammonium carbonate acted as a precipitant. The microstructure of the surface of the obtained samples was studied by scanning electron microscopy, and as a result it was found that the sample was represented by hollow spheres with a diameter of about 2 μm, the particle size of which varied from 40 to 250 nm. To determine the optimal type of interaction between particles and the stabilizer, computer quantum chemical modeling was carried out. It was found that the process of stabilization of nano-sized calcium carbonate and methylcellulose is energetically favorable. Also, to confirm the modeling results, the samples were examined by Fourier transform IR spectroscopy. Analysis of the results revealed that the interaction of CaCO3 nanoparticles occurs with the charged OH- group.
This work presents a method for the synthesis of calcium carbonate nanoparticles stabilized by methylcellulose. Calcium acetate was used as a precursor, and ammonium carbonate acted as a precipitant. The microstructure of the surface of the obtained samples was studied by scanning electron microscopy, and as a result it was found that the sample was represented by hollow spheres with a diameter of about 2 μm, the particle size of which varied from 40 to 250 nm. To determine the optimal type of interaction between particles and the stabilizer, computer quantum chemical modeling was carried out. It was found that the process of stabilization of nano-sized calcium carbonate and methylcellulose is energetically favorable. Also, to confirm the modeling results, the samples were examined by Fourier transform IR spectroscopy. Analysis of the results revealed that the interaction of CaCO3 nanoparticles occurs with the charged OH- group.
Теги: calcium carbonate nanoparticles scanning electron microscopy карбонат кальция наночастицы сканирующая электронная микроскопия
INTRODUCTION
Calcium carbonate is one of the most common nanomaterials, which has high biocompatibility and is used as a filler in polymer materials, as well as in the pharmaceutical, cosmetics and medicine industries [1–3]. Nanoscale materials are actively used in the healing of bone tissue regeneration; they imitate the structural features of bones and become a suitable class of materials for restoring bone structure [4, 5].
There are many methods for the synthesis of nanosized calcium carbonate, including chemical deposition from a gas mixture and the use of a high-pressure jet homogenizer [6, 7]. However, despite the high efficiency of these methods, they require additional costs and effort.
It is worth noting that calcium carbonate nanoparticles have certain disadvantages, such as a tendency to aggregation and sedimentation, which makes it difficult to use in some areas [8]. To overcome this problem, polymers can be used as stabilizers [9, 10]. One of the important factors in the synthesis of calcium carbonate nanoparticles is the choice of polymer type. For example, frequently used stabilizers that are highly biocompatible and biodegradable are chitosan, methylcellulose, glycosaminoglycans and gelatin [11–13]. The combination of polymers with biocompatible nanosized calcium carbonate particles can provide improved mechanical properties, osteoinductivity and increased affinity for bone cells [14–16].
The purpose of this work is to synthesize and study the properties of calcium carbonate nanoparticles stabilized by methylcellulose.
RESEARCH METHODS
CaCO3 nanoparticles stabilized by polymers were obtained by chemical deposition in an aqueous medium. Calcium acetate (Russia, Ch, JSC LenReaktiv) was chosen as the CaCO3 precursor. Methylcellulose (MC 100) (China, Ch) was used as a stabilizer, and ammonium carbonate (Russia, ChDA, LenReaktiv JSC) was used as a precipitant. Figure 1 shows a scheme for the synthesis of CaCO3 nanoparticles.
The method for obtaining CaCO3 nanoparticles is as follows: at the first stage, solutions of ammonium carbonate and calcium acetate with a concentration of 0.8 M were prepared using the precision weighing method. Next, 0.4 wt.% of stabilizer was added to the ammonium carbonate solution. At the next stage, a calcium precursor solution was added to the system. The resulting sols were washed by centrifugation. Next, the washed sediments were dried in an oven at a temperature of 80 °C.
Quantum chemical modeling of the interaction of calcium carbonate with methylcellulose was carried out using the QChem program. The construction of molecules was carried out in the molecular editor IQmol with the following construction parameters: calculation – Energy, method – B3LYP, basis – 6-31G*, convergence – 5, force field – Ghemical.
Quantum chemical modeling was carried out in two stages. At the first stage, modeling of methylcellulose molecules was carried out. At the second stage, the interaction of calcium carbonate with oxygen groups was considered through the interaction of the CO3– group through the calcium atom with oxygen.
Within the framework of quantum chemical modeling, the total energy of the molecular complex (E), the energy of the highest occupied molecular orbital (EHOMO) and the energy of the lowest unoccupied molecular orbital (ELUMO) were calculated. Based on the results obtained, the energy difference between the stabilizer and the molecular system “CaCO3 + MC” (∆E) and the chemical hardness of the molecular system (η), which characterizes the stability of the system, were calculated (formulas 1, 2):
ΔE = E1 – E2, (1)
where E1 is the total energy of the MC, kcal/mol; E2 – total energy of the “CaCO3 + MC” system, kcal/mol, and
, (2)
where ELUMO is the energy of the lowest free molecular orbital, eV; EHOMO – energy of the highest occupied molecular orbital, eV.
Micrographs and elemental composition of CaCO3 samples were obtained using a MIRA3-LMH scanning electron microscope (Tescan, Brno, Czech Republic) with an AZtecEnergy Standard/X-max 20 (standard) elemental composition determination system (Tescan, Brno, Czech Republic).
The study of vibrations of the bonds of functional groups in the obtained samples was carried out using the method of infrared spectroscopy on an FSM-1201 IR spectrometer with Fourier transform.
The color diagram was made using the site https://sciapps.sci-sim.com/CIE1931.html.
RESULTS
At the first stage, the microstructure of samples of nanosized calcium carbonate stabilized by methylcellulose was studied using scanning electron microscopy. The results are presented in Fig.2.
Next, computer quantum chemical modeling of the interaction of calcium carbonate nanoparticles with methylcellulose was carried out. The results of quantum chemical modeling of the interaction process are presented in Fig.3 and Table 1.
To confirm the simulation results, the samples were examined using IR spectroscopy. The results are presented in Fig.4.
DISCUSSION
Analysis of the obtained micrographs showed that the microstructure of CaCO3 nanoparticles stabilized by methylcellulose consists of aggregates representing hollow spheres with a diameter of about 2 μm. In turn, these clusters contain particles with sizes ranging from 40 to 250 nm.
As a result of quantum chemical modeling, it was found that the presented interaction models are optimal, since the difference in total energy is more than 939 kcal/mol.
It is worth noting that the model of interaction between CaCO3 and methylcellulose is energetically favorable, where binding occurs through the hydroxyl group attached to the C3 atom of the stabilizer and calcium in calcium carbonate. This fact is due to the large value of chemical hardness (0.022 eV) and the difference in total energy (939.398 kcal/mol).
Analysis of the IR spectrum of methylcellulose showed that in the region from 2800 to 3500 cm–1 the presence of bands of stretching vibrations of bonds is observed: the region from 2841 to 3478 cm–1 – vibrations of –CH bonds. In the same region from 2800 to 3500 cm–1 in the IR spectrum of CaCO3 stabilized by methylcellulose, there are stretching vibrations of bonds: at 2864 cm–1 – vibration of the –CH2 bond, at 2928 cm–1 – vibration of the –CH3 bond. In the IR spectrum of CaCO3, in the region from 2800 to 3500 cm–1 there are stretching vibrations: the region from 2910 to 2950 cm–1 – vibrations of –CH2 bonds, the region from 2990 to 3010 cm–1 – vibrations of –CH3 bonds. In the area from 650 to 1700 cm–1 in the IR spectrum of methylcellulose, deformation vibrations of bonds are observed: the region from 661 to 685 cm–1 – vibrations of –CH bonds, from 885 to 939 cm–1 – vibrations of –CH3 bonds, at 520 and 561 cm–1 characteristic bands are observed due to vibrations of –CH3 and –CH2 bonds, from 1022 to 1478 cm–1 – vibrations of –CH3 bonds, at 1622 and 1680 cm–1 – vibrations of C–C bonds. In the same region from 650 to 1700 cm–1 in the IR spectrum of CaCO3 stabilized by methylcellulose, there are bands of deformation vibrations: 711 and 873 cm–1 – vibrations of Ca–O bonds, in the region from 930 to 910 cm–1 – vibrations of bonds –CH3, at 1074 cm–1 – vibration of the CH3 bond, in the area from 1338 to 1500 cm–1 – vibration of the C–O bonds. In the same region from 650 to 1700 cm–1 in the IR spectrum of CaCO3, the presence of bending vibrations is observed: in the region from 1377 to 1504 cm–1 – vibrations of C–O bonds, at 709 and 875 cm–1 – vibrations of Ca–O bonds . As a result of the analysis of the IR spectra, it was established that in the spectrum of methylcellulose in the region from 1400 to 1420 cm–1 there is a decrease in the intensity of the bands that characterize the deformation vibrations of the charged OH– group. Thus, we can conclude that the interaction of CaCO3 nanoparticles occurs with the charged OH- group.
CONCLUSIONS
As part of the presented work, nanoparticles of calcium carbonate stabilized by methylcellulose were obtained by chemical precipitation. Analysis of SEM micrographs of CaCO3 nanoparticles stabilized by methylcellulose showed that the aggregates mainly have a regular hollow spherical shape and consist of particles ranging in size from 40 to 250 nm.
Investigation of the interaction process using computer quantum chemical modeling determined that the optimal interaction is where the binding occurs through the hydroxyl group of methylcellulose and calcium in calcium carbonate.
Confirming the chemical modeling data, studies of samples using IR spectroscopy showed that when CaCO3 nanoparticles are stabilized by methylcellulose, interaction occurs through the charged OH- group.
ACKNOWLEDGMENTS
The work was carried out with financial support from the Ministry of Science and Higher Education of the Russian Federation (project FSRN-2023-0037).
PEER REVIEW INFO
Editorial board thanks the anonymous reviewer(s) for their contribution to the peer review of this work. It is also grateful for their consent to publish papers on the journal’s website and SEL eLibrary eLIBRARY.RU.
Declaration of Competing Interest. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Calcium carbonate is one of the most common nanomaterials, which has high biocompatibility and is used as a filler in polymer materials, as well as in the pharmaceutical, cosmetics and medicine industries [1–3]. Nanoscale materials are actively used in the healing of bone tissue regeneration; they imitate the structural features of bones and become a suitable class of materials for restoring bone structure [4, 5].
There are many methods for the synthesis of nanosized calcium carbonate, including chemical deposition from a gas mixture and the use of a high-pressure jet homogenizer [6, 7]. However, despite the high efficiency of these methods, they require additional costs and effort.
It is worth noting that calcium carbonate nanoparticles have certain disadvantages, such as a tendency to aggregation and sedimentation, which makes it difficult to use in some areas [8]. To overcome this problem, polymers can be used as stabilizers [9, 10]. One of the important factors in the synthesis of calcium carbonate nanoparticles is the choice of polymer type. For example, frequently used stabilizers that are highly biocompatible and biodegradable are chitosan, methylcellulose, glycosaminoglycans and gelatin [11–13]. The combination of polymers with biocompatible nanosized calcium carbonate particles can provide improved mechanical properties, osteoinductivity and increased affinity for bone cells [14–16].
The purpose of this work is to synthesize and study the properties of calcium carbonate nanoparticles stabilized by methylcellulose.
RESEARCH METHODS
CaCO3 nanoparticles stabilized by polymers were obtained by chemical deposition in an aqueous medium. Calcium acetate (Russia, Ch, JSC LenReaktiv) was chosen as the CaCO3 precursor. Methylcellulose (MC 100) (China, Ch) was used as a stabilizer, and ammonium carbonate (Russia, ChDA, LenReaktiv JSC) was used as a precipitant. Figure 1 shows a scheme for the synthesis of CaCO3 nanoparticles.
The method for obtaining CaCO3 nanoparticles is as follows: at the first stage, solutions of ammonium carbonate and calcium acetate with a concentration of 0.8 M were prepared using the precision weighing method. Next, 0.4 wt.% of stabilizer was added to the ammonium carbonate solution. At the next stage, a calcium precursor solution was added to the system. The resulting sols were washed by centrifugation. Next, the washed sediments were dried in an oven at a temperature of 80 °C.
Quantum chemical modeling of the interaction of calcium carbonate with methylcellulose was carried out using the QChem program. The construction of molecules was carried out in the molecular editor IQmol with the following construction parameters: calculation – Energy, method – B3LYP, basis – 6-31G*, convergence – 5, force field – Ghemical.
Quantum chemical modeling was carried out in two stages. At the first stage, modeling of methylcellulose molecules was carried out. At the second stage, the interaction of calcium carbonate with oxygen groups was considered through the interaction of the CO3– group through the calcium atom with oxygen.
Within the framework of quantum chemical modeling, the total energy of the molecular complex (E), the energy of the highest occupied molecular orbital (EHOMO) and the energy of the lowest unoccupied molecular orbital (ELUMO) were calculated. Based on the results obtained, the energy difference between the stabilizer and the molecular system “CaCO3 + MC” (∆E) and the chemical hardness of the molecular system (η), which characterizes the stability of the system, were calculated (formulas 1, 2):
ΔE = E1 – E2, (1)
where E1 is the total energy of the MC, kcal/mol; E2 – total energy of the “CaCO3 + MC” system, kcal/mol, and
, (2)
where ELUMO is the energy of the lowest free molecular orbital, eV; EHOMO – energy of the highest occupied molecular orbital, eV.
Micrographs and elemental composition of CaCO3 samples were obtained using a MIRA3-LMH scanning electron microscope (Tescan, Brno, Czech Republic) with an AZtecEnergy Standard/X-max 20 (standard) elemental composition determination system (Tescan, Brno, Czech Republic).
The study of vibrations of the bonds of functional groups in the obtained samples was carried out using the method of infrared spectroscopy on an FSM-1201 IR spectrometer with Fourier transform.
The color diagram was made using the site https://sciapps.sci-sim.com/CIE1931.html.
RESULTS
At the first stage, the microstructure of samples of nanosized calcium carbonate stabilized by methylcellulose was studied using scanning electron microscopy. The results are presented in Fig.2.
Next, computer quantum chemical modeling of the interaction of calcium carbonate nanoparticles with methylcellulose was carried out. The results of quantum chemical modeling of the interaction process are presented in Fig.3 and Table 1.
To confirm the simulation results, the samples were examined using IR spectroscopy. The results are presented in Fig.4.
DISCUSSION
Analysis of the obtained micrographs showed that the microstructure of CaCO3 nanoparticles stabilized by methylcellulose consists of aggregates representing hollow spheres with a diameter of about 2 μm. In turn, these clusters contain particles with sizes ranging from 40 to 250 nm.
As a result of quantum chemical modeling, it was found that the presented interaction models are optimal, since the difference in total energy is more than 939 kcal/mol.
It is worth noting that the model of interaction between CaCO3 and methylcellulose is energetically favorable, where binding occurs through the hydroxyl group attached to the C3 atom of the stabilizer and calcium in calcium carbonate. This fact is due to the large value of chemical hardness (0.022 eV) and the difference in total energy (939.398 kcal/mol).
Analysis of the IR spectrum of methylcellulose showed that in the region from 2800 to 3500 cm–1 the presence of bands of stretching vibrations of bonds is observed: the region from 2841 to 3478 cm–1 – vibrations of –CH bonds. In the same region from 2800 to 3500 cm–1 in the IR spectrum of CaCO3 stabilized by methylcellulose, there are stretching vibrations of bonds: at 2864 cm–1 – vibration of the –CH2 bond, at 2928 cm–1 – vibration of the –CH3 bond. In the IR spectrum of CaCO3, in the region from 2800 to 3500 cm–1 there are stretching vibrations: the region from 2910 to 2950 cm–1 – vibrations of –CH2 bonds, the region from 2990 to 3010 cm–1 – vibrations of –CH3 bonds. In the area from 650 to 1700 cm–1 in the IR spectrum of methylcellulose, deformation vibrations of bonds are observed: the region from 661 to 685 cm–1 – vibrations of –CH bonds, from 885 to 939 cm–1 – vibrations of –CH3 bonds, at 520 and 561 cm–1 characteristic bands are observed due to vibrations of –CH3 and –CH2 bonds, from 1022 to 1478 cm–1 – vibrations of –CH3 bonds, at 1622 and 1680 cm–1 – vibrations of C–C bonds. In the same region from 650 to 1700 cm–1 in the IR spectrum of CaCO3 stabilized by methylcellulose, there are bands of deformation vibrations: 711 and 873 cm–1 – vibrations of Ca–O bonds, in the region from 930 to 910 cm–1 – vibrations of bonds –CH3, at 1074 cm–1 – vibration of the CH3 bond, in the area from 1338 to 1500 cm–1 – vibration of the C–O bonds. In the same region from 650 to 1700 cm–1 in the IR spectrum of CaCO3, the presence of bending vibrations is observed: in the region from 1377 to 1504 cm–1 – vibrations of C–O bonds, at 709 and 875 cm–1 – vibrations of Ca–O bonds . As a result of the analysis of the IR spectra, it was established that in the spectrum of methylcellulose in the region from 1400 to 1420 cm–1 there is a decrease in the intensity of the bands that characterize the deformation vibrations of the charged OH– group. Thus, we can conclude that the interaction of CaCO3 nanoparticles occurs with the charged OH- group.
CONCLUSIONS
As part of the presented work, nanoparticles of calcium carbonate stabilized by methylcellulose were obtained by chemical precipitation. Analysis of SEM micrographs of CaCO3 nanoparticles stabilized by methylcellulose showed that the aggregates mainly have a regular hollow spherical shape and consist of particles ranging in size from 40 to 250 nm.
Investigation of the interaction process using computer quantum chemical modeling determined that the optimal interaction is where the binding occurs through the hydroxyl group of methylcellulose and calcium in calcium carbonate.
Confirming the chemical modeling data, studies of samples using IR spectroscopy showed that when CaCO3 nanoparticles are stabilized by methylcellulose, interaction occurs through the charged OH- group.
ACKNOWLEDGMENTS
The work was carried out with financial support from the Ministry of Science and Higher Education of the Russian Federation (project FSRN-2023-0037).
PEER REVIEW INFO
Editorial board thanks the anonymous reviewer(s) for their contribution to the peer review of this work. It is also grateful for their consent to publish papers on the journal’s website and SEL eLibrary eLIBRARY.RU.
Declaration of Competing Interest. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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