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Section 15. Chemistry
Aripova Mastura Khikmatovna, Tashkent Chemical Technological Institute, Department of "Technology of silicate materials and rare precious metals", Dr. Technical Sciences, Professor E-mail: aripova1957@yandex.ru Kadirova Zuhra Chingizovna, Tashkent Chemical Technological Institute, Center of Excellence, Dr. Engineering, PhD in Chemistry, E-mail: zuhra_kadirova@yahoo.com Mkrtchyan Ripsime Vachaganovna, Tashkent Chemical Technological Institute, Innovation Centre, PhD in Technical Sciences E-mail: mk_hripsime@mail.ru
Influence of bioglass composition on interaction with polyacrylic acid
Abstract: The composition effect on interaction between polyacrylic acid and bioglass synthesized in the system RO-CaF2-P2O5-Al2O3-SiO2 (R = Ca, Zn) were studied by Fourier Transformed Infrared Spectroscopy (FTIR). The influence of glass structure on intermolecular interactions was established. It was determined that critical factor for polyacrylic acid adhesion to glass surface is content of zinc oxide. Composition of bioglasses affects both the strength of adhesion of polyacrylic acid to glass, and the intermolecular interactions in the system. The process of acid-base interaction between polyacrylic acid and glass components has been completed in 24 hours and three-dimensional structure is formed via strong intermolecular bonds providing hardening material.
Keywords: bioglass, polyacrylic acid, adhesion, FTIR spectroscopy.
Glass polylkenate cement is a class of modern dental materials designed by combination of properties of silicate and polyacrylic systems. Originating as a result of development for replacement of silicate cements used in dentistry more than 100 years, glass poly-acrylate cements have become an important component of the modern dentistry.
Glass polyalkenate cements are powder-liquid systems. The alu-minafluorinesilicate glasses with certain particle sizes are used as a powder, and an aqueous solution of polyacrylic acid or copolymers are used as a liquid.
We have investigated influence of the composition of bioglasses synthesized in the system RO-CaF2-P2O5-Al2O3-SiO2 (R = Ca, Zn) on interaction with polyacrylic acid.
The powdered polyacrylic acid (~0.1% cross-linked, average Mv ~450,000) produced by SIGMA-ALDRICH CHEMIE GmbH used in experiments. Different glass compositions were used for preparation of composites with polyacrilic acid solution at room temperature. FTIR spectra were registered at different time period. Fig. 1-2 shows FTIR spectra observed at 30 minutes and 24 hours after mixing of glass powder with polyacrylic acid solution. The selected glass compositions were:
C-1-4,32SiO2; 3,67Al2O3; 6,30ZnO; 42,05CaO; 37,47P2O5; 6,19CaF.
C-5-8,64SiO2; 7,33Al2O3;
12,60ZnO; 34,05CaO; 32,74P2O
2 5^
4,64CaF.
C-7-4,32SiO2; 3,67Al2O3;
25,20ZnO; 27,04CaO; 35,90P O
25
3,87CaF.
The infrared spectra were recorded in KBr pellets using FTIR instruments (IRAffinity-1, Shimadzu, Japan) and IRSolution software. The wavelength range was set between 4000 cm-1 and 400 cm-1.
FTIR spectra of initial polyacrylic acid is shown in Fig. 1a and characterized by a number of characteristic absorption bands. The group of frequencies in the range of 1696-1738 cm-1, indicating the presence of internal and intermolecular hydrogen bonds in structure of polyacrylic acid. Stretching vibrations OH associated with car-boxyl-group are attributed to frequency in range of 2668 cm-1, and OH bending vibrations correspond frequency in range of 925 cm-1 [1, 183-200].
Result of interaction between the 40% polyacrylic acid solutions with selected bioglasses of different composition (C1, C5, C7 samples) at 0.5 hours after mixing is shown in Fig. 1 b-d.
Main characteristic vibration frequency of polyacrylic acid has a slightly different intensity and more blurred. Vibration frequency of carbonyl group is shifted and observed in typical range at 1710 cm-1.
The acid-base interaction of polyacrylic acid components with bioglass leads to possible resonance between two C-O bonds. The absorption vibration bands appeared in the region 1610-1550 and 1400-1300 cm-1, which are corresponded to symmetric and asymmetric vibrations of COO groups [1, 183-200]. There are intense characteristic absorption bands of silicates and phosphates at 400650 and 1000-1100 cm-1 [2, 118]. The region of characteristic hy-droxyl groups ofwater molecules vibrations expanded to broad band at 3600 cm-1.
Influence of bioglass composition on interaction with polyacrylic acid
Figure 1. FTIR spectra of samples (a - polyacrylic acid, b - C5-polyacrylic acid, c -C1 -polyacrylic acid, d - C7-polyacrylic acid, e - C7, f - C1, g - C5)
It is well known [1, 183-200], that v (C = O) absorption frequency depends on the electron-donor and acceptor properties of the carbonyl group substituent. The carboxylate anion absorption frequencies are equal to 1580, 1565 and 1560 cm -1 for the C-1, C-5 and C-7 glass composition, correspondingly. This change can be attributed to different content of zinc oxide inside glass composition. The acid-base interaction of polyacrylic acids with alkalineearth metals of bioglasses can lower carbonyl group absorption. Previously, the strongest interaction of polyacrylic acid with zinc oxide was determined by molecular dynamics computer simulation
method [3, 199-201]. Changing the zinc content in the glass affects the interaction force between polyacrylic acid and glass, and it is manifested in corresponding decrease of the carbonyl group absorption frequency.
The band at 2668 cm-1 is disappeared which indicates the absence of hydroxyl groups bonded via strong hydrogen bonds.
The value of difference between asymmetric and symmetric carboxylate-ion vibration frequencies (Av) is calculated to determine the bond type of the polydentate carboxylate ion with bioglass metals (Table. 1) [4, 64-65].
Table 1. Characteristic carboxylate ion vibration frequency in FTIR spectra in composite samples of polyacrylic acid-bioglass synthesized in the system RO-CaF2-P2O5-Al2O3
.3-SiO2 (R = Ca, Zn)
Bioglass index Va (CO,") Vs (CO,) AV Structure
C-1 1580 1400 180 chelating
1451 129 bridging
C-5 1565 1412 153 chelating
C-7 1560 1413 147 chelating
1451 109 bridging
The monodentate complexes are not existed which is confirmed by lack of characteristic bands in the range of920-720 and 540 cm-1 [4, 64-65]. It is known that number of bands in chelate complexes are less, and spectra of the C-5 glass — polyacrylic acid sample is characterized by a smaller number of absorption bands.
Analysis of obtained experimental data suggests the presence of chelating and bridging structures of materials prepared by interaction between polyacrylic acid with C-1 and C-7 glasses, as well as,
chelate structure of C-5 bioglass compositions. It can be explained due to the C-5 composition sample has increased content of silicon and aluminum oxides in two times, and apparently high levels of these oxides does not promote the formation of bridge bonds.
The spectra of the materials obtained after 24 hours after mixing of polyacrylic acid and bioglasses have no corresponded to carbonyl groups (Rg. 2).
Figure 2. FTIR spectra of C1 -polyacrylic acid composition after 24 hours
Thus, it is possible to conclude that the process of acid-base interaction between polyacrylic acid and glass components has been completed because three-dimensional structure is formed via strong intermolecular bonds providing hardening material. Composition of bioglasses obtained in the system RO-
CaF2-P2O5-Al2O3-SiO2 (R = Ca, Zn) affects both the strength of adhesion of polyacrylic acid to glass, and the intermolecular interactions in the system. Determining factors are the contents of zinc oxide, silicon oxide and aluminum oxide in the glass composition.
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2. Plyusnina I. I. Infrared spectra ofminerals. - M.: Moscow State University, 1977. - 182 p.
3. Aripova M. H., Mkrtchyan R. V., Kadirova Z. C. Assessing the interaction of acrylic acid with a biocompatible glass molecular dynam-ics//IV Int. Conf. of Chemistry and Chemical Technology. Yerevan, September 14-18, - 2015. - P. 199-201.
4. Nakamoto K. Infrared and Raman Spectra of Inorganic and Coordination Compounds: Part A: Theory and Applications in Inorganic Chemistry, Sixth Edition, John Wiley & Sons, - 2009. - 400 p.
