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МЕЖДУНАРОДНЫЙ НАУЧНЫЙ ЖУРНАЛ «ИННОВАЦИОННАЯ НАУКА» №6/2015 ISSN 2410-6070
ХИМИЧЕСКИЕ НАУКИ
УДК 543.831:541.183
O. V.Dyakonova
assistant professor, S. A.Sokolova assistant professor, V. V.Kotov
professor
The Faculty of Technology and Merchandizing Voronezh State Agricultural University after Emperor Peter the Great
Voronezh, Russian Federation
THE STRUCTURE AND PROPERTIES OF ION-EXCHANGING POLYAMIDE ACID MEMBRANES SYNTHESIZED AT VARIOUS TEMPERATURES
Abstract
The peculiarities of structure of new ion-exchanging polyamide acid membranes, received by thermal processing of a solution of a copolymer 1,2,4,5-benzoltetracarbonic acid with 4,4'-diaminediphenyloxide in dimethylformamide were researched. By a method of IR-spectroscopy it is shown, that depending on temperature of synthesis it is possible to vary over a wide range the contents of functional carboxyl groups, and also the correlation of amide and imide groups in a phase of a membrane and, as a result, to change its physical and chemical properties. By means of methods of a nuclear magnetic resonance (NMR) with a pulse gradient of a magnetic field and electronic spin resonance (ESR) structural characteristics of transport channels in gel phase of membranes are determined. Distinctions in structure of membranes, received at different temperatures, are proved also by a method of reference porometry.
Keywords
Polyamide acid membrane; Synthesis; Ion-exchanging; Structure; IR-spectroscopy; Reference porometry; NMR-spectroscopy; Self-diffusion coefficients; ESR-spectroscopy.
1. Introduction
The receiving of new membrane materials, possessing high selectivity, thermo stability, mechanical durability, is a necessary condition for wide use of membrane processes of division in the solution of urgent technological and ecological problems. In this connection the big interest represents polyamide membranes, received by the thermal processing of aromatic polyamide acids (PAA).
While changing the temperature of influention on PAA, we have received the materials, combined properties of the ionexchanges membranes, the polyamides (PA) and polyimides (PI) [1]. The received membranes are characterized by a wide range of a variation of an exchanging capacity, optimal hydrophobic-hydrophyilic balance, good thermal stability, high selectivity to one-charged cations of metals.
The information on structural peculiarities as to a surface, and a volumetric phase of membranes is necessary for revealing mechanisms of functioning of the given membranes in various processes of division. With this purpose the whole complex of physical and chemical methods of research has been involved: sorption, IR-, NMR-spectroscopy, reference porometry, scanning probe microscopy.
2. Experimental Part 2.1. The thermal synthesis polyamide acid membranes
The polyamide acid membranes were synthesized by two-leveled thermal processing of 12-20% solution of polyamide acids - an aromatic copolymer 1,2,4,5- benzoltetracarbonic acid with 4,4'- diaminediphenyloxide in dimethylformamide (DMPA), produced on NPO "Plastic", Moscow. Molecularly-mass distribution of a copolymer was within the limits of 15-55 ths. c.u. The weight of an elementary link made up 418 c.u., and the contents of carboxyl groups 4.18 mmol/g of dry substance.
The substrate with the solution of PAA was located in an autoclave, where as a result of thermal processing, was exposed
to imidization. At the first step at the temperature of 353K within one hour the gradual removing of a great mass of solvent
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МЕЖДУНАРОДНЫЙ НАУЧНЫЙ ЖУРНАЛ «ИННОВАЦИОННАЯ НАУКА» №6/2015 ISSN 2410-6070 took place. Then the temperature in the autoclave was increased to the set one on the second step, at which within 30 minutes the process of elimination of waters with formation of imid links, and also removing of the rests of solvent and formed water from a product of thermal processing took place. The temperature of the second step of synthesis changed within the limits of 383-573K. After the consummation of the process the formed polymers together with the substrate were cooled, and then processed by the distilled water with the purpose of exfoliation from a substrate, washed and dried up on air. As a result came out thin pellicles with a smooth surface.
2.2. Preparation of membranes for researches For reducing membranes to balance with working solutions, they were placed in flasks with the ground stoppers and maintained with periodic updating a solution before the beginning of the experiment not less than for three day. As working solutions of electrolytes were used the solutions: HCl, NaCl, СаСЬ, MgCh, CuCh, CoCh, and NiCh. Solutions were prepared according to accurately weighed reagents. As the solvent the distilled water with specific resistance not less than 5-105Om-1 •cm-1 was used. The analysis of solutions was spent by standard methods [2].
For transferring membranes in sodium or calcium salt form weighed air-dried membranes with the different exchanging capacity, weighed on analytical weights, was processed with 0.01M of a solution of sodium hydroxide or calcium hydroxide, taken in amount equivalent to number of carboxyl groups in samples. Then membranes were washed by the distilled water and were balanced with corresponding solutions of chlorides of sodium or calcium.
2.3. Definition of the basic physical and chemical characteristics polyamide acid membranes Process of imidization is usually characterized by a limit of transformation PAA in PI, to which the degree of imidization is taken, representing the ratio of the given concentration imide connection in polymer to most possible. The degree of imidization was determined by the contents of residual carboxyl groups in imidizated PAA, by direct potentiometric titrations of 0.01M by a solution of hydroxide sodium [1]. On dependence of pH-volume of titranium the point of equivalence was installed. After carrying out of the analysis the exchanging capacity E films in mmol/g were calculated by the equation:
E = VNaOH ' ^NaOH I mMb (1),
where Vnoh and Cnooh - volume and concentration of the alkali, which have gone on titration; тмь - weight of a membrane. The received values of exchanging capacity were used for calculation of degrees of imidization of PAA (R) according to the equation:
R = (Eo- E )/Eo (2), where Ео and E - accordingly are exchanging capacity of initial polyamide-acid and its product of thermal imidization. Eo, calculated from the formula of elementary section of PAA, made up 4.78 mmol/g.
2.4. Method of IR-spectroscopy Air-dry samples of membranes were maintained for three day in the desiccator at the room temperature of 313K. IR-spectra were gathered with the instrument Spekord-IR-75 in an interval of 400-4000cm-1. Processing of IR-spectra passed by calculating of positions of maxima (cm-1) in a spectrum of the investigated sample [3].
2.5. Method of NMR with a pulse gradient of a magnetic field In the study of membranes by NMR pulse magnetic field gradient membrane samples were placed in weighing bottles with distilled water and incubated for 48 hours. To measure the NMR spectrometer swollen membranes after removing the external water were placed in standard vials, which were immediately sealed. To measure self-diffusion coefficients of water molecules was used the pulse sequence "stimulated echo" - 90(g5)x-90-i1-90-(g5)x-echo, where g - amplitude, 5 - duration of pulses of magnetic field gradient. Frequency of proton NMR was 100MHz. The values of self-diffusion coefficients Ds i and the relative share of the diffusantpi in the membrane was determined from the analysis of the dependency of the spin-echo signal amplitude on g2 (diffusion decay), which was approximated by the following equation:
N
a(g2) = Zp i exp(- r252g2tdDsi) (3)
Pi exP ' 2r T1 ' v T2i Tu J
ж X Pi exP i ' 2t Tx V T2i TXl
(4),
Ti, T2 - the times of the nuclear spin-lattice and spin-spin relaxation, y - gyromagnetic ratio of the resonating protons, t - the time interval between the first and second radiofrequency (RF) pulses, ti - the time interval between the second and the third ones, td = À-S/3 - the time of diffusion, where A - the interval between the pulses of the magnetic field gradient, N - number of phases, if the membrane is not uniform [4].
2.6. Method of ESR
ESR-spectra were registered on spectrometer ER-420 Endor of firm Bruker at temperature 293K [5]. PAA membranes have been studied in the copper-sour form, received by partial washing out of ions of copper from membranes by 0.1M solution of a hydrochloric acid.
2.7. Method of reference porometry
In conducting the research of porometry, the previously weighed on an analytical balance package of investigated swollen membranes was placed in a clamping device between the two standards with a known distribution of pore radius. Drying was carried out at a set of298K. After removal by evaporation of some amount of a fluid, all the samples were weighed, and then the current value of the removed water volume for each sample was calculated. Next, using porometry curve for the standards the value of the pore size was determined, corresponding to the value of volume. All definitions were repeated until virtually complete removal of fluid from the investigated membranes. According to reports received by the reference value of pore radius and the current values of remote volumes of water, referred to the weight of the dry sample, the porometric curve was based [6].
3. Results and discussion 3.1. The condition of water in PAA membranes with a various degree of imidization according to IR-spectroscopy
IR-spectrograms are brought on Figure 1. The condition of water in ion-exchangers characterizes an area of spectrograms within the limits of frequencies 3675-2400cm-1. Character of change of spectral characteristics in this area testifies to strengthening process of dehydration with rising temperature of synthesis PAA membranes. In the field of 3627-3420cm-1 maxima, typical for associates of "water-water" with anti-regulated structure (with one - two hydrogen connections on a molecule of water- 3627, 3527, 3467cm-1) are shown.
For the characteristic of parameters of hydrogen connection the equations on which it is possible to calculate its energy ÀЕн, enthalpy of formations ÀН, and also lengths ofhydrogen bridges hydrogen-oxygen (-COOH-OH2) Ro.o and hydrogen-nitrogen (-CO-NH—OCO ) Rn.o have been used:
-EH =iUv/v°OH )/l.6 (5) [7]
-AH = (Dv/80)V2 • 2.9 (6) [7]
R0...0 = 2.84 - (□ v/4400) (7) [8] Rn~o = 3.21 —(DV/548) (8) [8],
where OH - typical frequency corresponding to completely anti-regulated structure of water (3675cm-1), Av -displacement of typical frequency of a maximum.
Figure 1. IR-spectrograms of PAA membranes. The temperature of synthesis, K: 1-393; 2-423; 3-473; 4-523; 5-573.
The results of calculation of thermodynamic characteristics in this area are brought in Table 1. In comparison with structure of "free" water energy of hydrogen connections in membranes is characterized by smaller size ~ 20 kJ/mol. Accepting an assumption, that energy of the hydrogen connection, calculated according to the equation 5, represents free energy of formation of hydrogen connection, the change of entropy, which for the given structures close to change of entropy of freezing of water (22 J-K-1-mol-1) has been calculated. Partial dehydration is one of the reasons of formation of intermolecular and intramolecular hydrogen connections that follows from display of maxima in the field of 3328cm-1 ("water ... -NH"), 2667cm-1 ("water... 0=C < in carboxylic and carbonylic groups") and 2491cm-1 (connection -COOH... H2O... NH<).
On sizes of intensities of maxima (Figure 1) distribution of water with various coherence in membranes has been calculated. Calculation of intensities of characteristic maxima was spent by a method of a base line regarding their intensity (hi) to intensity of maximum well shown on spectrograms 3050cm-1 (ho), characteristic to valence vibrations C-H groups in benzolic cycles [8].
Table 1.
The parameters of hydrogenous bridge in PAA membranes in H +- form.
Tsynthesis , K (the degree of imidisation,%) V, cm-1 лу, cm-1 -Ен, kJ-mol-1 -ли, kJ-mol-1 Ro...o, Â Rn...o, Â лs, J-K-1- mol-1
3627 48 3.4 9.4 2.83 - -20.1
3567 108 7.7 14.1 2.82 - -21.5
3467 208 14.8 19.6 2.79 - -16.1
393 (17.8) 3420 255 18.2 21.7 2.78 - -11.7
3328 347 24.7 25.3 2.76 2.58 -4.0
3276 399 28.4 27.1 2.75 - +4.4
3167 508 36.2 30.6 2.72 - +18.8
2667 1008 71.8 43.1 2.61 - +96.3
2491 1184 84.3 46.7 2.57 1.05 +126.2
423 2650 1025 73.0 43.5 2.61 - +99.0
(36.6) 2452 1223 87.1 47.5 2.56 0.98 +132.9
473 2630 1045 74.4 43.9 2.60 - +102.3
(70.9) 2450 1225 87.2 47.5 2.56 0.97 +133.2
523 (90.0) 2440 1235 87.9 47.7 2.56 0.96 +134.9
Then there was defined the percentage of water, Ci, corresponding i - to a maximum, under the formula:
„ _ hi / ho
-100%
(9)
S
hi / h
О
On the Figure 2 the dependences Ci on a degree of imidization of PAA membranes in the hydrogen form are shown. All curves can be divided in two groups - decreasing and increasing with increase of degree of imidization. The first group of curves (1,2,3) corresponds to area of strong hydrogen connections, such as free water of swelling (3420cm-1) and water of hydrated capsules at imino- (3328cm-1) and carboxylic (2667cm-1) groups. Reduction of the maintenance as free, and hydrated waters is connected with dehydration of membranes, that greater, than the temperature of synthesis and a degree imidization is higher. Especially strongly this effect is shown at 2667cm-1 (OH2...O=C<) in carboxylic and carbonylic groups.
1
Figure 2. The dependence of relative distribution of water, Ci in PAA membranes in the hydrogen form from a degree imidization, R. Frequencies of characteristic maxima, cm-1: 1-2667; 2-3328; 3-3420; 4-3467; 5-3567; 6-3627.
The second group of curves (4,5,6) corresponds to water with anti-regulated structure (maxima 3627, 3567, 3467cm-1). The increase in its maintenance is connected with increase of a degree of imidization, accompanied by replacement of molecules of water from hydrated capsules imino-and carboxylic groups. It proves by reduction of the maintenance of the water corresponding these groups (maxima 3328 and 2667cm-1). At rather low degrees of imidisation any significant advantage of size doesn't have any of the kinds of water. Molecules are in regular intervals distributed between fragments of polymer and carry out a role of "greasing" at the migration of ions in PAA membranes that is also characteristic for ion-exchanging membranes on the basis of polyamides [9].
3.2. The results of reference porometry researches of polyamide acid membranes
Water in PAA membranes has a wide range of distribution on pores from 1 up to 10000nm. With the increase of temperature of synthesis the hydrophobization of polymeric matrix is observed. Thus reduction in a share of the water containing in large pores, passes more intensively, than in fine. Comparison of curves Figure 3 shows, that the relation of the maintenance of water in fine pores (about 1nm) makes 1.1-1.2, while in large (1000-1000 nm) - 1.8-2.0.
Figure 3. Integrated curves of distribution of water, V on radiuses of pores, r of PAA membranes. Temperature of reception of membranes, K: 1-383; 2-393; 3-403; 4-423.
On the Figure 4 the differential curve distributions of pores on radiuses of PAA membranes are brought. The character of curves speaks about a significant share of fine pores in the samples received at all temperatures that is expressed available narrow maxima in the field of about 1 nanometer. These maxima correspond to area gel sites of the membranes containing connected water in hydrated capsules of fixed ions, anti-ions and in micropores. The comparison of data of Figure 4 with results IR - spectroscopic research of distribution of water in PAA membranes (Figure 1) allows to assume, that "anti-regulated" water with one-two hydrogen connections between molecules is more characteristic just for these micropores. Thus water with a normal grid of hydrogen connections should be redistributed in larger pores.
Figure 4. The differential curve of the distributions of pores on radiuses of PAA membranes in the hydrogen form. Temperature of reception of membranes, K: 1-383; 2-393; 3-403; 4-423.
For the membranes received at the temperatures 383-403K (Figure 4.b, curves 1-3), in the field of Igr = 0,5-2,0 (r = 3-100nm) on dependences are observed the horizontal sites parallel to an axis of absciss. It specifies in regular intervals changing
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polydispersity of PAA membranes in the given area. Thus with rise in temperature of synthesis at preservation of the same character of polydispersity the share of pores of this interval on curves gradually decreases, that specifies course of process stiching polymeric circuits. As to a curve 4 (Figure 4.b), describing PAA membrane received at temperature 423 K in an interval lgr =0,2-2,0 AV/Algr =0, that speaks about absence in structure of membranes of pores of the given size.
The significant differences are observed at the membranes received at 423K, close to temperature of boiling of solvent DMPA. Two maxima observable at lgr = 2.5 and 3.6 (accordingly the radiuses of pores of 3-102 and 4-103nm) testify to major defects in structure of PAA membranes in the field of meso- and macropores [10].
3.3. The self-diffusion of water and features of structure of membranes according to EPR and NMR with a pulse gradient of a magnetic field The small molecules are entered into a phase of a membrane as diffusant, are an original molecular probe by means of which it is possible to receive the information on structure of transport channels in a membrane [4].
For samples of membranes in Na+- form, with factor of a moisture capacity 5-6 molecules of water falling an average molecular part of polymer, the dependence of amplitude of a signal of a spin echo on size of a square of a gradient of a magnetic field (diffusion decay) is two-exponential (Figure 5). This fact proves the presence of transport channels of two various types in structure of membranes, time of an exchange of molecules between which is much more than time of diffusion td, sold in experiment. Thus, mobility of molecules of water can be characterized by two values of self-diffusion coefficients Dsi and D&. At 20°С self-diffusion coefficients Dsi and DS2, and also relative shares of water in channels land 2 are accordingly equal 9.110-10m2/s and 3.510-11m2/s, 0.54 and 0.46. As value of coefficient Dsi is close to similar size for free water at the same temperature (Ds=2.3 • 10-9m2/s), it is possible to assume, that the channel 1 represents large inter gel sites in a phase of polymer (defective areas).
a
Si 0 -
-2
3
(I 50(1 1000 1500
g2, T2 m 2
Figure 5. The dependence of water spin-echo signal, A on the square of gradient g2 (the diffusion decay) in the
polyamide acid membrane at low water content.
The size of coefficient DS2 is comparable to similar values in ionogenic transport channels of membranes on the basis of sulpho-containing aromatic polyamides [12]. Therefore with the larger probability it can be confirmed, that the transport channel 2 represents areas with the increased local concentration of charged functional groups (carboxylate anions COO ) and connected with them hydrated counterions.
The existence of ionogenic transport channels in a phase of a membrane proves by the data received by method of ESR of ions Cu2+, on samples of PAA membranes in the mixed copper-sour form. The analysis of the form of spectrum ESR (Figure 6) demonstrates existence in a phase of polymer of areas with the increased local concentration of carboxylic groups and contra-ions of copper. The structure, formed by functional groups, contra-ions and molecules of water microclusters (complexes) corresponds to the formula [Cu(H2O)4](COO)2. Microclusters will organize ionogenic spending channels for molecules of water, which mobility is follows from the given above data of NMR, it is essential lower, than in free water.
Figure 6. ESP spectrum of Cu2+in polyamide acid membrane recorded at room temperature.
At a room temperature the rotation of complexes [Cu(H2O)4](COO)2 is complicated, hence, the sizes of ionogenic channels are comparable to the sizes of tetraaquacomplexes of copper (II) and make the size about 1 nm. The temperature dependences of average self-diffusion coefficients submit to the Arrhenius law. The average values of the factors of self-diffusion of water in PAA-membranes depend on temperature of their reception, and consequently, from their structure. For membranes received at temperatures 383, 403 and 423K, sizes of energy of activation of self-diffusion of water have made accordingly 25.3; 23.3; 19.0 kJ/mol. These sizes well correlate with data for sulpho-containing aromatic polyamides, where carry of molecules of water at low moister containing (factor of a moisture capacity of 5-6 molecules of water on an elementary part of polymer) is carried out by overjump of molecules from one center of hydration to another [12-14]. Apparently, the similar situation is realized and in the PAA-membranes. The centers of hydration here are ionogenic groups and contra-ions. The diffusive moving of molecules of water is limited in the ionogenic transport channels.
4. Conclusions
1. The research of a condition of water in PAA membranes has revealed their rather low moisture content, the less, than the degree of imidisation is higher. Thus for rather low-temperatured membranes, the distribution of water between elements of structure takes place. Hydrophobisation of membranes with increase of a degree of imidisation is accompanied by redistribution of water between functional groups of a matrix and inter gal sites, consisting in reduction in quantity of water at a polar groups and increase of a share of water with the disordered structure.
2. The data of porometric researches have shown, that in structure of PAA membranes, synthesized at temperatures 303-403K, there is a significant share of fine pores of radius about of 1 nanometers. With growth of temperature of synthesis (more 423K) the course of process of stitching polymeric circuits amplifies, and also in the structure of membranes there are macropores of radius about 3-102 and 4-103 nanometers, that testifies about significant defect-making, shown near to temperature of boiling of solvent - dimethylformamide (426K).
3. The diffusion mobility of molecules of water are carried out in the ionogenic transport channels having the size about 1 nanometer, and in defective inter gal sites (macropores) of a polymeric phase. And self-diffusion coefficients of water in various structural channels differ almost on the order. The transfer of water molecules in the solid phase of the membranes of limited diffusion in ionogenic transport channels.
5. Reference
[1] O.V. Dyakonova, V.V. Kotov, V.F. Selemenev, "The Exchange of Properties of Poliamid Acid Pellicles with Varying Degrees of Imidization," Russ. J. Phys. Chem., Vol. 72, No. 7, 1998, pp. 1275-1279.
[2] Yu.Yu. Lurie "Analytical chemistry of industrial wastewater," - Moscow: Chemistry, 1984, p. 448.
[3] V.A. Uglyanskaya, T.A. Chikin, V.F. Selemenev, T.A. Zavyalova, "Infra-red Spectroscopy of ion-exchange Materials," - Voronezh, Voronezh State University Press, 1989, p. 208.
[4] A.I. Maklakov, V.D. Skirda, N.F. Fatkullin, "Self-diffusion in Polymer Solutions and Melts," Kazan, Kazan State University Press, 1987, p. 224.
[5] V. I. Volkov, S. F. Timashev, "Magnetic Resonance Methods in the Investigation of Perfluorinated Ionexchange Membrane," Russ. J. Phys. Chem., Vol. 63, No. 1, 1989, pp. 108-116.
[6] N.P. Berezina, Y.M. Volfkovich, N.A. Kononenko, "The Study of the Distribution of Water in the heterogeneous ion-exchanging Membranes using Reference Porometry, " Russ. J. Elektrohimiya, Vol. 23, No. 7, 1987, pp. 912-916.
МЕЖДУНАРОДНЫЙ НАУЧНЫЙ ЖУРНАЛ «ИННОВАЦИОННАЯ НАУКА» №6/2015 ISSN 2410-6070
[7] A. V. Iogamsen "Infrared spectroscopy and spectral definition of the hydrogen bond energy," - Moscow: Science, 1981, p. 111.
[8] G.C. Pimentel, A.L. McClellan, The Hydrogen Bond, Reinhold, New York, 1960
[9] J.E. Kirsch, I.M. Malkina, Y.A. Fedotov, S.F. Timashev, "Selective Transfer of monovalent and divalent Cations in the sulfonate-containing aromatic polyamides Membranes," Russ. J. Phys. Chem., Vol. 67, No. 11, 1993, pp. 23122314.
[10] Y.M. Volfkovich, V.K. Luzhin, A.N. Vanyulin, "Application of the Reference Porometry for the Study of the porous Structure of ion-exchange Membrane," Russ. J. Elektrohimiya , Vol. 29, No. 5, 1993, pp. 656-664.
[11] V.I. Volkov, S.A. Korotchkova, I.A. Nesterov, J.E. Kirsch, S.F. Timashev, "The Particularities of water State and Mobility in sulfocontaining aromatic polyamide Membranes on the pulse NMR data, " Russ. J. Phys. Chem., Vol. 68, No. 7, 1994, pp. 1310-1316.
[12] V.I. Volkov, S.A. Korotchkova, H. Ohya, Q. Guo, "Self-diffusion of water-ethanol Mixtures in polyacrylic asid-polysulfone composite Membranes obtained by pulsed-field gradient nuclear magnetic Resonance Spectroscopy," Journal of Membrane Science, Vol. 100, 1995, pp. 273-286.
[13] V.I. Volkov, V. D. Skirda, E. N. Vasina, S.A. Korotchkova, H. Ohya, K. Soontarapa, "Self-diffusion of water-ethanol Mixtures in chitosan Membranes obtained by pulsed-field gradient nuclear magnetic Resonance technique," Journal of Membrane Science, Vol. 138, 1998, pp. 221-225.
[14] O.V. Dyakonova, S. A. Sokolova, V. V. Kotov, V. I. Volkov, "The Structure and electrochemical Properties of cation-exchange Membranes based on partially imidized polyamide acid," Russ. J. Elektrohimiya , Vol. 38, No. 8, 2002, pp. 994-997
© O.V. Dyakonova, S.A. Sokolova, V.V. Kotov, 2015
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БИОЛОГИЧЕСКИЕ НАУКИ
УДК: 579
Е.О. Качанова
студентка 5 курса ИВСЭБиПБ, Е. В. Павлова, к.б.н., проф.
Московский государственный университет пищевых производств
Г. Москва, Российская Федерация
ИССЛЕДОВАНИЕ АНТАГОНИСТИЧЕСКОЙ АКТИВНОСТИ ПРОБИОТИКА «ЭМ-КУРУНГА»
Аннотация
В статье представлены основные сведения о пробиотике «Эм-Курунга», и данные наших экспериментов его антагонистической активности по отношении к условно-патогенной микрофлоре слизистых оболочек пищеварительного тракта в сравнении с другими пробиотиками.
Ключевые слова
Пробиотик «Эм-Курунга», антагонистическая активность пробиотика «Эм-Курунга».
Что такое «Эм-Курунга»?
«Эм-Курунга» является пробиотиком, который представляет собой кисломолочный продукт - закваску. Впервые, «Эм-Курунга» была создана в Бурятии, под руководством д. м. н. П. А. Шаблина около десяти лет назад. На основе бурятского национального кисломолочного продукта - курунги - был создан новый симбиотический комплекс «ЭМ-Курунга» путём обогащения продукта эффективными микроорганизмами (ЭМ), представителями постоянной микрофлоры кишечника - бифидобактериями и пропионовокислыми бактериями. Бифидобактерии подавляют развитие условно-патогенных и патогенных микроорганизмов, стимулируют перистальтику кишечника, способствуя нормальной эвакуации его содержимого, обладают витаминообразующей функцией. Есть данные о противоопухолевом воздействии бифидобактерий. Также они разрушают канцерогенные вещества, образуемые некоторыми представителями кишечной флоры при азотном обмене, выполняя при этом роль «второй печени». Бифидобактерии играют важную роль в поддержании иммунной системы организма человека. Пропионовокислые бактерии известны своими антимутагенными и кобаламинсинтезирующими свойствами, которые способствуют профилактике раковых заболеваний и анемии.
В результате синтеза курунги с «ЭМ» новый препарат «Эм-Курунга» стал содержать максимально возможное количество полезных микроорганизмов:
- кисломолочные палочки и кокки, дрожжи, уксуснокислые бактерии, входящие в состав курунги;
- «эффективные микроорганизмы» - пропионовокислые бактерии и бифидобактерии. [2]
Антагонистическое действие пробиотика «Эм-Курунга»
При проведении нами сравнительного анализа антагонистической активности «Эм-Курунги» по отношению к возбудителю пищевых токсикоинфекций и представителю условно-патогенной микрофлоры пищеварительного тракта (E. coli) методом «лунок» с пробиотиками Лактобифадол, Бактисубтил, Ветом 1.1. было выявлено, что более сильной антагонистической активностью к E. coli обладает пробиотик «Эм-Курунга»:
Таблица 1
Задержка роста культуры E.coli исследуемыми пробиотиками.
Пробиотик Задержка роста E.coli
Эм-Курунга 35.2 +0.5 мм
Лактобифадол 10.1 + 012 мм
Бактисубтил 21.54+2.011 мм
Ветом 1.1 11.13+1.26 мм
