Semchikov Yu.D. Macromolecular compounds - file n1.docx. Radical copolymerization of acrylate and methacrylate guanidines with vinyl monomers. Usually, the determination of the effectiveness of flocculants in relation to a certain type of water pollutant is concluded

As a manuscript

Sapaev Hussein Khamzatovich

Radical copolymerization

acrylate and methacrylate guanidines with vinyl monomers

02.00.06 - Macromolecular compounds

dissertations for a degree

candidate of chemical sciences.

Nalchik-2009

The work was carried out at the Department of Macromolecular Compounds of the State Educational Institution of Higher Professional Education “Kabardino-Balkarian State University

them. HM. Berbekov”

Scientific adviser: doctor of chemical sciences, professor

Malkanduev Yusuf Akhmatovich

Official opponents: Doctor of Chemistry, Professor

Rusanov Alexander Lvovich

doctor of chemical sciences, professor

Beriketov Anuar Sultanovich.

Lead organization: Institute of Petrochemical

synthesis them. A. V. Topchiev RAS

The defense of the dissertation will take place on _______June_2009. at _____ hours at a meeting of the dissertation council D 212.076.09 at the Kabardino-Balkarian State University. HM. Berbekov at the address: 360004, KBR, Nalchik, Chernyshevsky, 173, building 11, conference room.

The dissertation can be found at the Scientific Information Center of the KBSU named after M. HM. Berbekov.

Scientific Secretary

dissertation council T.A. Borukaev

GENERAL DESCRIPTION OF WORK

Relevance of the topic. The development of science and technology puts forward at the present stage the problems of obtaining new polymeric materials with a given set of properties. That is why in recent decades in the field of chemistry of macromolecular compounds, the creation and study of synthetic polyelectrolytes has been intensively developed. They are widely used in various fields of industry, technology, agriculture, medicine, and in the future their role and importance will undoubtedly increase.

It is known that compounds containing a guanidine group in their composition have a wide spectrum of bactericidal action and are often used as therapeutic agents, bactericides, and fungicides. In this regard, the synthesis of new copolymers of various compositions based on acrylate guanidine (AG) and methacrylate guanidine (MAG) is of particular interest, since the introduction of a guanidine group into polymer products should impart significant biocidal activity to them. This is especially true for aqueous solutions of flocculants, in particular, polyacrylamide (PAA), which is easily subjected to microbiological degradation in the presence of bacteria and mold.

During radical polymerization and copolymerization of water-soluble monomers, the nature of the reaction medium significantly affects the kinetic parameters of the synthesis and the characteristics of the resulting products. This is due to a change in the reactivity of the reacting particles due to their ionization, solvation, complex formation, and intermolecular interactions in the reaction medium. Therefore, the complicated nature of the copolymerization of ionogenic monomers also determines the relevance of studying the features of the formation of guanidine-containing copolymers based on vinyl monomers.

Considering the above, we believe that the synthesis and study of the properties of new guanidine-containing copolymers opens up new possibilities for the synthesis of polymers with the required set of properties.

The purpose of the work and the main objectives of the study. The purpose of this work was to study the possibility of obtaining new high-molecular copolymers based on AG and MAG with acrylamide (AA) and guanidine monomaleate (MMG) in aqueous solutions and, taking into account these results, the directed synthesis of new cationic polymers with biocidal properties, the study of the mechanism and kinetics characteristics of these reactions. To achieve this goal, it was necessary to solve the following tasks:

1. Investigation of the possibility of obtaining new copolymers based on AG and MAG with AA and MMG and synthesizing new cationic polyelectrolytes based on them.

2. Establishment of the main kinetic regularities of the radical copolymerization of AG and MAG with AA and MMG in aqueous solutions, determination of copolymerization constants and intrinsic viscosity.

3. Study of the influence of the structure and properties of polymerizing particles on the kinetics and mechanism of radical copolymerization.

4. Study of the physicochemical, bactericidal, toxicological and flocculating properties of the synthesized monomeric and polymeric products.

Scientific novelty. The principal possibility of participation of AG and MAG in reactions of radical copolymerization with AA and MMG is shown; the kinetic regularities were studied and the copolymerization constants of these processes were calculated.

The main physicochemical properties of the synthesized polymer products were studied by spectroscopic (IR-, NMR1H), thermophysical (DSC, TGA) methods, as well as by elemental analysis. Techniques have been developed that make it possible to obtain these copolymers with specified parameters (composition, structure, molecular weight).

For the first time, based on AG and MAG, new guanidine-containing water-soluble copolymers with AA and MMG of various compositions and structures were obtained by radical copolymerization.

The biocidal and toxicological properties of the resulting polymer products were evaluated. It has been shown that a number of guanidine-containing AA copolymers have low toxicity. The highest biocidal properties are exhibited by copolymers with AA containing 30-70 mol. % acrylate component. It was revealed that copolymers of MAG with MMG exhibit pronounced fungicidal properties.

The flocculating properties of new guanidine-containing copolymers AA with AG and MAG have been studied and the possibility of their use in water purification processes has been shown.

The practical value of the work. As a result of joint studies with the Bacteriological Laboratory of the State Sanitary and Epidemiological Surveillance of the KBR and with the pharmaceutical association "Elpharmy" (KBR, Nalchik), it was found that the synthesized copolymers have significant biocidal activity against gram-positive and gram-negative microorganisms, and copolymers with MMG have a pronounced fungicidal activity. Along with biocidal properties, the copolymers have low toxicity, and with an increase in the units of the acrylate component in the copolymer, the toxicity decreases. It was found that AA copolymers with MA and AG have effective flocculating properties; found the optimal conditions for their use in water purification processes. The most pronounced flocculation properties have a copolymer of AA with MAG composition 70:30. At the same time, the presence of guanidine units in the macromolecules of AA copolymers makes the flocculant resistant to biodegradation under the influence of bacteria and mold.

Approbation of work. The main results of the work were reported and discussed at the III All-Russian Scientific and Practical Conference "New Polymer Composite Materials" (Nalchik, 2007), the I All-Russian Scientific and Technical Conference "Nanostructures in Polymers and Nanocomposites" (Nalchik, 2007), the All-Russian Scientific and practical conference of young scientists, graduate students and students. (Grozny, 2008), All-Russian Scientific and Practical Conference "Environmental Situation in the North Caucasus: Problems and Ways to Solve Them". (Grozny, 2008).

Publication of results On the topic of the dissertation, 8 articles were published, including 1 article in a journal recommended by the Higher Attestation Commission of the Russian Federation.

The structure and scope of the dissertation. The dissertation consists of an introduction, a review of the literature, an experimental part, a discussion of the results, conclusions and a list of cited literature. The work is presented on 129 pages of typewritten text, including 24 tables, 32 figures. The bibliography includes 210 titles.

MAIN CONTENT OF THE WORK

Chapter I The main kinetic regularities and features of the reaction of radical polymerization of acrylic series monomers in aqueous solutions with a change in various parameters (pH, temperature, change in monomer concentration) and in the presence of various neutralizing agents were considered. An analysis of the literature data presented allows us to conclude that the observed kinetic features are mainly due to specific interactions between charged macroradicals and low molecular weight counterions present in the reaction solution. It was also undoubtedly important to evaluate the effect of the nature of the reaction medium on the polymerization of the monomers under consideration, in particular, to carry out a comparative analysis of the kinetic data for the polymerization of acrylic acids in organic solvents and in aqueous solutions.

ChapterII. The experimental part is presented. Objects, methods of research, methods of carrying out synthesis and kinetic studies are considered.

starting materials. AG and MAG are synthesized from guanidine and acrylic (methacrylic) acid. MMG is a qualified product of the brand "ch.d.a." firm "Acros". The initiator was ammonium persulfate (APS) (NH4)2S2O8, ethanol was anhydrous according to the standard procedure, diethyl ether was dried over alkali and distilled twice over metallic sodium. Acetone was dried over CaCl2, then boiled and distilled twice over Р2О5.

Research methods. The kinetic features of the radical copolymerization of AG and MAG with AA were studied by the dilatometric method. The intrinsic viscosity of polymer solutions was determined in a Ubellode viscometer. As a solvent for measuring intrinsic viscosity, 1 N NaCl solutions were used. In the work, physicochemical research methods were used - elemental analysis, IR and PMR spectroscopy, viscometry, DTA, DSC.

Chapter III.The discussion of the results

3.1 Radical copolymerizationguanidine acrylateAnd guanidine methacrylateWithacrylamide

Water-soluble copolymers of AA with salts of acrylic and methacrylic acids, depending on the molecular characteristics, are used as flocculants and stabilizers of disperse systems, thickeners and structuring agents. Taking into account the high biocidal activity of guanidine-containing compounds, which have long been successfully used in medicine and in various fields of industry, it seemed necessary to study the possibility of synthesizing new copolymers based on guanidine-containing acrylic monomers and AA. Since it would be natural to expect that the newly created copolymers can exhibit new important properties and characteristics that are not inherent in the original homopolymers. Along with the expected practical significance of these polymers, the study of the kinetic features of the course of the reaction of radical copolymerization is undoubtedly relevant in the scientific aspect, primarily from the standpoint of assessing the reactivity of the synthesized monomers under the conditions under consideration.

Before carrying out systematic kinetic studies in the copolymerization systems under consideration, the optimal conditions for the implementation of these reactions were determined - an aqueous medium; total concentration of copolymers [M] = 2 mol l-1; [PSA]=510-3 mol l-1; 600C.

The composition of the AA:AG copolymers was determined from elemental analysis data, since the chemical shifts of –CH2–CH= protons in the 1H NMR spectra of the comonomers are similar and overlap. The data are shown in Table 1.

Table 1

Elemental Composition Data for AA:AG Copolymers

Ref. composition AG:AA	WITH	N	H	R = N/C in copolymer
Ref. composition AG:AA	Mass., %
80:20	38.85	29.33	6.90	0.755
50:50	41.99	26.62	6.96	0.634
40:60	41.85	26.74	6.80	0.639
20:80	44.15	24.77	7.30	0.561
10:90	47.37	22.31	7.00	0.471

To calculate the content of comonomers, we used the ratio of the content of nitrogen and carbon in the copolymer R = N/C (%), based on the consideration that

NSP \u003d NAGX + NАА (1 - X) (1)

CSP \u003d CAGX + CAA (1 - X), (2)

where NAG and CAG are the content in AG, NAA and CAA are the content in AA, X is the proportion of AG in the copolymer, and (1 – x) is the proportion of AA in the copolymer.

From here we have the equation:

NAGX + NАА(1 - x)

CAGX + CAA(1 - x)

Solving this equation and substituting the values for the content of nitrogen and carbon in the corresponding comonomers, we obtain expressions for calculating X, i.e. share of AG in the copolymer. Calculation of the composition of copolymers AA with MAG was carried out according to the data of 1H NMR spectroscopy, using the integral intensity of the signal of the methyl group of the MAG comonomer, which manifests itself in the strongest field and is not overlapped by any other signals. One third of its integral intensity will be equal to the value of the conditional proton for the MAG link - “1H (M2)”. The protons related to the signals of the CH2 groups of the copolymer chain appear for both comonomers together in the range of chemical shifts of 1.5–1.8; therefore, to determine the conditional proton of the unit АА “1Н (М1)”, the contribution of two protons (I) was subtracted from the total integrated intensity of these protons (I). link MAG and the remaining value was divided by 2 (equation 4):

“1H (M1)” = (I - 2 “1H (M2)”) : 2 (4)

From the results obtained, the molar content of comonomers in the copolymer, expressed in mol.%, was determined (equations 5 and 6):

MPAA = [“1H (M1)” : (“1H (M1)” + “1H (M2)”)]100% (5)

MPMAG = [“1H (M2)” : (“1H (M1)” + “1H (M2)”)]100% (6)

As can be seen from the curves in Fig. 1, at all initial molar ratios of comonomers, the copolymer is enriched in acrylate comonomer units, and the MAG–AA system is characterized by a greater enrichment in MAG comonomer, in contrast to the AG–AA system. This indicates a higher reactivity of MAG in the reaction of radical copolymerization and corresponds to the data on the parameters of the reactivity of acrylic (AA) and methacrylic (MAA) acids available in the literature. The greater reactivity of the MAG monomer compared to AG is probably due to the greater delocalization of the charge of the carboxyl group in the monomer molecule, as indicated by the shift of the vinyl proton signals of MAG to a stronger field compared to AG in the 1H NMR spectra. The lower reactivity of acrylamide compared to AG and MAG may be due to the specific structure of ionogenic

Rice. 1. Dependence of the composition of the formed copolymers in the systems:

AG-AA (curve 1) and MAG-AA (curve 2)

from the composition of the initial reaction solution

monomers, in which there is an electrostatic attraction between the positively charged ammonium nitrogen atom and the carbonyl oxygen atom of the methacrylic acid residue, the electron density of which is increased (Scheme 1).

where, R= H, CH3

Scheme 1. Zwitterionic delocalized structure of AG and MAG

This attraction causes delocalization of the negative charge along the bonds of the carboxylate anion AA and MAA. Due to this delocalization, the relative stability of the corresponding radicals is higher compared to acrylamide. In the case of MAG, there is a higher delocalization of electrons in the C–O– bond in methacrylate anion compared to AG, which is confirmed by the greater enrichment of copolymers in MAG comonomer compared to AG.

Because Since we studied copolymerization at low degrees of conversion, we used the analytical method to calculate the copolymerization constants; the values of the constants calculated by this method are presented in Table 1. 2.

table 2

AG (MAG) (M1) -AA (M2)

Given in table. 2 r1 values< 1 и r2 < 1 свидетельствует о предпочтительном взаимодействии макрорадикалов с «чужим», чем со «своим» мономером в обеих сополимеризационных системах. Значения произведения r1r2 < 1 говорит о выраженной тенденции к чередованию в обеих сополимеризационных системах. Кроме того, r1>r2, which confirms that the probability of addition of comonomer radicals to the monomeric MAG and AG molecule is somewhat higher than to the AA molecule. The closeness of the relative activities to unity during MAG-AA copolymerization indicates that the chain growth rates in this system are controlled by the rate of diffusion of monomer molecules into macromolecular coils, and the rates of diffusion of comonomers differ little from each other.

Thus, the radical copolymerization of AA with AG and MAG makes it possible to obtain copolymers with a high content of ionogenic groups.

However, despite the fact that our values of relative activities indicate a lower reactivity of the AA monomer compared to MAG and AG, the study of the copolymerization of these comonomers in aqueous solutions showed that as the concentration of ionogenic AG and MAG comonomers in the initial reaction mixture increases, intrinsic viscosity values decrease.

To understand the mechanism of copolymerization of AG and MAG with AA, the rate of this process in an aqueous solution was studied by the dilatometric method. PSA was used for initiation.

A study of the kinetics under these conditions showed that the copolymerization of AG and MAG with AA proceeds only in the presence of radical initiators and is completely suppressed when an effective radical inhibitor 2,2,6,6, tetramethyl-4-oxylpyridyl-1-oxyl, is introduced into the reaction solution. A spontaneous reaction—polymerization in the absence of a radical initiator—is also not observed.

The reaction solutions were homogeneous over the entire range of compositions, and the resulting copolymers were highly soluble in water.

It is shown that in the studied reaction, the dependence of the degree of conversion on the duration of the reaction under the selected conditions (aqueous medium; total concentration of copolymers [M] = 2 mol l-1; [PSA]=510-3 mol l-1; curve up to a conversion of 5-8%.

The study of the kinetics of copolymerization showed that with an increase in the content of the ionic monomer in the initial monomer mixture, the values of the initial polymerization rate 0 and intrinsic viscosity decrease symbatically during the copolymerization of AA with AG and MAG (Fig. 2).

Fig.2. Dependence of the initial rate of copolymerization (1.4) and intrinsic viscosity (2.3) of the copolymer MAG with AA (1.2) and AG with AA (3.4) on the content of ionogenic monomer in the initial reaction mixture

Moreover, for the first system (during polymerization with AG), the course of this dependence is more pronounced. The results obtained are in good agreement with the known literature data obtained in the study of the kinetics of the copolymerization of N,N-diallyl-N,N-dimethylammonium chloride (DADMAC) with AA and MAA in aqueous solutions. In these systems, it was also found that the rate of copolymerization decreases with an increase in the content of DADMAC in the initial reaction solution, and this increase is more pronounced for AA than for MAA.

From fig. It also follows from Table 2 that the highest molecular weight samples of copolymers (judgment by values) are obtained in monomeric mixtures with a high content of AA.

Apparently, the most probable reason for the observed decrease in the chain growth rate constant with an increase in the concentration of ionogenic comonomer is that the concentration of strongly hydrated acrylate and methacrylate anions in relatively hydrophobic uncharged coils of macroradicals is lower than their average concentration in solution, which is indirectly confirmed by decrease in the reduced viscosity of the copolymer solution with an increase in the content of AG and MAG units.

It is more logical to associate the decrease with the structuring effect of AG and MAG ions on water molecules, which leads to a decrease in volumetric effects, i.e. the quality of water as a solvent for PAA deteriorates.

Obviously, the phenomena observed during radical copolymerization with the participation of ionizable AG and MAG monomers cannot be explained only on the basis of classical concepts, and the parameters r1 and r2 can only serve as conditional values reflecting the influence of certain factors on the behavior of a given monomer at copolymerization.

Thus, in all likelihood, the observed features and differences in the series of monomers under consideration are explained by the complex nature of the contributions of various physicochemical processes that determine the course of the copolymerization reaction of AA with guanidine-containing monomers of the acrylic series. At the same time, we believe that the main contribution to the change in the effective reactivity of polymerizing particles is made by associative interactions between guanidine and carboxyl groups (both intra- and intermolecular) and the structural organization of the corresponding monomers and polymers during copolymerization.

To establish the equation for the overall rate of copolymerization of AA with AG and MAG, experiments were carried out for variable concentrations of AA, AG, MAG, and the components of the initiating system, while maintaining the constancy of the concentrations of the remaining components of the reaction system and reaction conditions.

3.2. Radical copolymerization of acrylate guanidine and methacrylate guanidinewith guanidine monomaleate

Radical homopolymerization and copolymerization of guanidine-containing compounds is the object of study by many authors, mainly in connection with the possibility of obtaining polymeric materials with a complex of specific properties, including biocidal ones. However, there is little information in the literature regarding the study of the processes of radical copolymerization of ionogenic monomers containing the same functional groups.

In this regard, the study of the processes of copolymerization of guanidine-containing ionogenic monomers seemed to us to be very relevant.

It is known that maleates, due to the symmetry of the structure, spatial factors, and the high positive polarity of the vinyl group, do not form homopolymers in the presence of radical initiators. The experimental results obtained in this work also showed that the homopolymerization of MMG under the studied conditions is difficult. So, for example, the degree of conversion of the MMG monomer into a polymer under the conditions ([MMH] = 2 mol l-1; 600C; [PSA] = 510-3 mol l-1; H2O; polymerization time 72 hours) is about 3% ( = 0.03 dl r-1). All these facts indicate a significant contribution of the above factors to the process of homopolymerization of the system studied by us.

At the same time, it is important to note that in the study of the reaction of radical copolymerization of MMG with MAG, a number of copolymers of various compositions with rather high intrinsic viscosities were obtained.

Radical copolymerization was studied in aqueous solutions, PSA was used as an initiator ([I] = 10-2 – 10-3 mol l-1) in the temperature range (40 - 600C). It was previously established that polymerization does not occur in the absence of an initiator.

The copolymerization was carried out to various degrees of conversion, and the following patterns were revealed. In all cases, the formation of copolymers enriched in MAG units compared to the initial mixture of comonomers is observed (Table 3), which indicates a higher reactivity of MAG in chain propagation reactions. Copolymerization occurs only with an excess of guanidine methacrylate. If there is an excess of guanidine MMG, neither copolymerization nor homopolymerization of MAG is observed.

Table 3

Dependence of the composition of the copolymer on the initial composition of the reaction solution during the copolymerization of AG (MAG) (M1) and MMG (M2)

2.00 mol/l, [PSA]= 5 10-3 mol l-1, H2O, 600C.

No. p / p	Starting comonomers	Copolymers M1:M2,
	М1:М2, mol.%	AG-MMG mol.%	, dl/g	MAG-MMG mol.%	, dl/g
1	40:60	90:10	0.35	75:25	0.15
2	50:50	95:5	0.55	68:32	0.20
3	70:30	75:25	0.88	90:10	0.27
4	80:20	97:3	0.93	96:4	0.41
5	90:10	98:2	0.98	98:2	0.53

Note. was determined at 300C in 1N NaCl aqueous solution.

The composition of the synthesized polymer products was confirmed by 1H NMR and IR spectroscopy.

The predominant contribution of the steric factor to the reactivity of MMG in the copolymerization reaction with AG and MAG is confirmed by the values of the copolymerization constants, which are presented in Table 4.

Table 4

The value of effective copolymerization constants in systems

AG (MAG) (M1) - MMG (M2)

([M]sum = 2 mol l-1; [PSA]=510-3 mol l-1; 600C; H2O)

3.3 Physicochemical and biocidal properties of synthesized copolymers

NMR study1 H and IR spectroscopy The polymer compounds synthesized in the present work confirmed the proposed structure of the objects of study. The study of the 1H NMR spectra of the synthesized copolymers made it possible to determine the comonomer composition by analyzing the integrated intensities of various signals.

A study by differential thermal analysis (DTA) and differential scanning calorimetry (DSC) of the synthesized copolymers revealed their high thermal stability, and the copolymers turned out to be more resistant to high temperatures than the original homopolymers (the studies were carried out up to a temperature of 10000C). So for PAA, a 30% weight loss is observed already at a temperature of 170 0C, for the AA-MAG (90:10) copolymer, a 30% weight loss is observed at 300 0C, and for a 30:70 copolymer at 280 0C.

Studies of bactericidal activity showed a priori expected significant bactericidal and fungicidal activity for a number of copolymer compositions. It was revealed that copolymers AA-MAG (70:30), (50:50), (10:90) have the highest biocidal activity against Staphylococcus aureus. Biocidal activity depends on the amount of AG and MAG in the macromolecular chain. In relation to Candida albicans, the samples AA-MAG (10:90) and AA-AG (20:80) turned out to be the most active.

Copolymers of AG and MAG with MMG are not active against the studied microorganisms, but have a high fungicidal activity against the pathogenic fungal microflora Candida albicans, it is noteworthy that the corresponding homopolymers exhibit bactericidal activity, but do not have fungicidal activity. Thus, the greatest antifungal effect was obtained for samples of copolymers MAG with MMG with the initial composition of comonomers 50:50 and 70:30.

Toxicity study of a number of copolymers of AA with MAG and AG using the bioindicator Daphnia magma Strauss revealed that the toxicity of the samples depends on the composition of the copolymers, with an increase in the content of acrylate and guanidine methacrylate, the toxicity of polyacrylamide flocculants decreases.

Investigation of the flocculating properties of new acrylamide copolymers

An aqueous suspension of kaolin was used as a model system to evaluate the flocculating activity of polyelectrolytes.

Since the flocculating ability is affected by the charge of the macromolecule, copolymers with different degrees of content of acrylate monomer units in the macromolecular chain were chosen for the study. PAA was used as an object of comparison.

In Fig.3. shows the effect of the concentration of flocculants of different composition on the flocculating effect (F), which was calculated by formula (1)

F = (n0 - n) / n, (1)

where n0 and n are, respectively, the optical density of water (determined by the turbidimetric method) in the absence and presence of a flocculant (and a coagulant).

Fig. 3. Dependence of the flocculating effect F on the concentration and composition of 1-PAA copolymers; 2-AG-AA (20:80); 3-AG-AA (40:60); 4- MAG-AA (20:80); 5- MAG-AA (40:60); 6- MAG-AA (30:70)

Experiments carried out on one batch of natural water (turbidity 4.2 mg l–1, color 48.5 degrees) showed an increase in the flocculating effect with an increase in the concentration of the copolymer for all flocculants. This is a consequence of an increase in the concentration of macromolecular bridges formed during the adsorption of macromolecules on the surface of particles of the dispersed phase, which formed large aggregates of particles of the dispersed phase and macromolecules and reduced the stability of the system.

It was revealed that samples of MAG-AA copolymers are characterized by large values of F in comparison with AG-AA. Comparison of the data at a constant concentration of flocculants indicates an increase in the values of F upon transition to copolymers with a higher content of MAG and AG units. Corresponding to the norm F = 0.7 (determined at n = 0.172 and = 364 nm, corresponding to the turbidity of purified water) is achieved at lower concentrations of the AA: MAG copolymer compared to PAA.

The maximum flocculating effect is observed in the 70:30 copolymer. Obviously, in this case, the optimal ratio between the charge density and the flexibility of macromolecules is realized, which ensures that the polymer bridges cover a larger number of particles of the dispersed phase, increase the size of the floccules and the flocculating effect.

The determination of the residual copolymer in purified water using the Burket method showed the absence of a polymer in purified water, which indicates that under the studied conditions, the copolymers almost completely interact with colloidal particles.

CONCLUSIONS

1. For the first time, the composition, structure and some properties of new copolymers based on AG and MAG with AA and MMG were synthesized and established by a complex of physicochemical methods.

2. The kinetic features of the radical copolymerization of AG and MAG with AA and MMG in aqueous solutions were studied, the copolymerization constants and intrinsic viscosities were determined.

3. It was found that the decrease in the rate of copolymerization with an increase in the concentration of the ionogenic monomer is associated with a specific feature of the structure and properties of the polymerizing particles, which results in an increase in the termination constant.

4. It has been established that during the radical copolymerization of guanidine-containing monomers in aqueous media with an excess of MMG, low molecular weight polymers are formed, which is caused by the significant influence of spatial factors and the high positive polarity of the MMG vinyl group in connection with which this monomer does not form homopolymers.

5. Bactericidal and toxicological tests of the synthesized copolymers based on AG and MAG were carried out on a number of cell cultures. It is shown that with significant biocidal activity, they are characterized by low toxicity. High antifungal activity of AG and MAG copolymers with MMG was found.

6. The flocculating properties of AA copolymers with AG and MAG have been determined and the optimal conditions for their effective use in the processes of water purification and disinfection have been found.

Sapaev, Kh. Kh. New polyfunctional nanocomposites based on clay minerals and biocidal polymers for water treatment [Text] / Kh. Kh. Sapaev., S. Yu. Khashirova., A. V. Labazanova., Yu. A. Malkanduev / / I-th All-Russian scientific and technical conference "Nanostructures in polymers and polymer nanocomposites". - Nalchik.: KBGU, 2007. - S. 245 - 249.
Sapaev, Kh. Kh. Features of reactions of radical polymerization of acrylate- and methacrylate guanidines [Text] / Kh. Kh. Sapaev., S. Yu. Khashirova., N. A. Sivov., Yu. scientific-practical conference "New polymer composite materials". - Nalchik.: KBGU, 2007. - S. 160 - 164.
Sapaev, Kh. Kh. Conformational behavior of growing chains of poly (meth) acrylate guanidines in aqueous solutions [Text] / Kh. Kh. Sapaev., S. Yu. Khashirova., N. A. Sivov., Yu. A. Malkanduev // III All-Russian scientific and practical conference "New polymer composite materials". - Nalchik.: KBGU, 2007. - S. 149 - 153.
Sapaev, Kh. Kh. Radical polymerization of nitrogen-containing diallyl monomers [Text] / Kh. Kh. Sapaev., S. Yu. Khashirova., Yu. - Grozny.: ChGU, 2008. - S. 154 - 162
Sapaev, Kh. Kh. Modification of cellulose with biocidal polyelectrolytes [Text] / Kh. Kh. Sapaev., S. Yu. Khashirova., Yu. Situation in the North Caucasus: Problems and Ways to Solve Them. - Grozny.: ChGU, 2008. - S. 414 - 419.
Sapaev, Kh. Kh. Copolymers of guanidine-containing ionic monomers are effective biocidal polymers [Text] / Kh. Kh. Sapaev., S. Yu. Khashirova., Yu. : problems and ways to solve them. - Grozny.: ChGU, 2008. - S. 419 - 424.
Sapaev, Kh. Kh. Chemical modification of cellulose with guanidine methacrylate [Text] / Kh. Kh. Sapaev., S. Yu. Khashirova., Yu. A. Malkanduev // Vestnik ChGU. - 2008 - No. 2. - S. 50 - 53.
Sapaev Kh.Kh. Study of biocide-toxicological characteristics of new polyacrylamide flocculants [Text] / Kh.Kh. Sapaev., S.S. Pekar., S.Yu. Khashirova., Yu.A. Malkanduev // Magazine "Plastic masses". - 2008. - No. 5, - S. 53-54.

The author considers it his duty to express his deep gratitude to N.A. Sivov, Ph.D. for help and scientific advice during the dissertation work.

Radical copolymerization is usually initiated by the same methods as radical homopolymerization. The elementary stages of radical copolymerization proceed according to the same mechanisms as in homopolymerization.

Consider the copolymerization of two monomers. Assuming that the activity of growing radicals is determined only by the type of the terminal unit, four elementary chain propagation reactions should be taken into account when describing the reaction kinetics:

Growth response Growth response rate

~R 1 + M 1 ~R 1 k 11

~R 1 + M 2 ~R 2 k 12

~R 2 + M 1 ~R 1 k 21

~R 2 + M 2 ~R 2 k 22

where M i --monomer i-ro type; ~R j is a macroradical ending with a unit M j , k ij is the rate constant of addition of the M j monomer to the ~R i radical.

Kinetic processing of the above reaction scheme in the quasi-stationary approximation makes it possible to establish a relationship between the composition of the copolymers and the composition of the initial mixture of monomers. In the quasi-stationary state, the concentrations of the radicals ~R 1 - and ~R 2 - are constant, i.e., the rates of cross-growth of the chain are equal to each other:

k 12 = k 21 (1-6)

The rates of conversion of monomers during copolymerization are described by the equations

For the ratio of the rates of these reactions, we get:

Eliminating the stationary concentrations of radicals from this equation and using the quasi-stationarity condition (1.6), we obtain the expression

here r 1 = k 11 / k 12 and r 2 = k 22 / k 21 -- the so-called copolymerization constants. The values of r 1 and r 2 are the ratios of the rate constants of attachment to a given radical of "own" and "foreign" monomers. The values of r 1 and r 2 depend on the chemical nature of the reacting monomers. At the initial stages of the transformation, when the monomer concentrations and [M 2 ] can be assumed to be constant without a large error, the composition of the copolymer will be determined by the equation

where [] and are the concentrations of monomer units in the macromolecule.

The dependence of the composition of copolymers on the composition of a mixture of monomers is conveniently characterized by a diagram of the composition of the monomer mixture - the composition of the copolymer (Fig. 1.1). The shape of the resulting curves (1 - 4) depends on the values of r 1 and r 2 . In this case, the following cases are possible: 1) r 1 = r 2 = 1, i.e., for all ratios of monomer concentrations in the reaction mixture, the composition of the copolymer is equal to the composition of the initial mixture; 2) r1 > 1, r2< 1, т. е. для всех соотношений концентраций мономеров в исходной смеси сополимер обогащен звеньями M 1 ; 3) r 1 < 1, r 2 >1, i.e., for all initial ratios of monomer concentrations, the copolymer is enriched in M 2 units; 4) r1< 1 и r 2 < 1, т. е. при малых содержаниях M 1 в исходной смеси мономеров сополимер обогащен звеньями М 1 а при больших - звеньями М 2 . В последнем случае наблюдается склонность к чередованию в сополимере звеньев M 1 и М 2 , которая тем больше, чем ближе к нулю значения r 1 и r 2 , Случай, r 1 >1 and r 2 > 1, which should correspond to the tendency for separate polymerization of monomers in a mixture, is not implemented in practice.

The constants r 1 and r 2 can be determined experimentally. Knowing them makes it possible to predict the composition of the copolymer and the distribution of monomer units in the chains at any ratio of monomers in the mixture. The values of r 1 and r 2 during radical copolymerization and, consequently, the composition of the copolymer usually weakly depend on the nature of the solvent and change little with temperature.

Rice.

Table 1.2. Radical Sopblimerization Constants for Some Monomers

Consideration of the constants r 1 and r 2 in the framework of the theory of ideal radical reactivity leads to the conclusion that r 1 \u003d r 2 \u003d 1, i.e., the rate constants for the addition of one of the monomers to both radicals are the same number of times greater than the rate constants for the addition of the other monomer to these radicals. For a number of systems, this condition is well justified experimentally. In such cases, monomeric units of both types are arranged randomly in macromolecules. However, for many systems r 1 x r 2< 1, отклонения связаны с влиянием полярных и пространственных факторов, которые обусловливают тенденцию мономерных звеньев M 1 и M 2 к чередованию в макромолекулах. В табл. 1.2 в качестве примеров приведены значения констант сополимеризации и их произведений для некоторых пар мономеров.

Scheme "Q - e". Accounting for polar factors was made within the framework of a semi-empirical scheme called the "Q - e" scheme, in which it is assumed that

k 11 = P 1 Q 1 exp(-e 1 2 )

and k 12 = P 1 Q 2 exp(-e 1 e 2 )

where P and Q are the parameters corresponding to the conjugation energies in the monomer and the radical, according to the theory of ideal radical reactivity; e 1 and e 2 are quantities that take into account the polarization of the reacting monomers and radicals.

r 1 \u003d Q 1 /Q 2 exp (-e 1 (e 1 -e 2))

and likewise

r 2 \u003d Q 2 /Q 1 exp (-e 2 (e 2 -e 1))

Using this scheme, one can estimate the relative reactivity of monomers and the role of polar factors for a large number of pairs of copolymerizable monomers. Styrene is usually taken as a standard monomer with the values Q = 1, e = -0.8. During the copolymerization of styrene with other monomers, the latter are characterized by their Q and e values, which makes it possible to predict the behavior of these monomers in copolymerization reactions with other monomers, for which Q and e values have also been established. Although the “Q-e” scheme does not yet have a complete theoretical justification, in practice she was very helpful. The Q and e values of most monomers are collected in the reference literature.

UDC 541.64:547.32:547.371

Radical Copolymerization of Styrene and Unsaturated Glycidyl Ethers

M.A. Chernigovskaya, T.V. Raskulova

Angarsk State Technical Academy,

665835, Irkutsk region, Angarsk, st. Tchaikovsky, 60, [email protected]

Abstract—The binary radical copolymerization of unsaturated glycidyl ethers (allyl glycidyl ether, ethylene glycol vinyl glycidyl ether) with styrene in toluene has been studied. The copolymerization constants and the microstructure of the resulting copolymers were calculated. It has been established that the composition of the copolymers depends on the structure of the unsaturated glycidyl ether. Copolymers of allylglycidyl ether with any composition of the initial monomer mixture are close in their structure to alternating ones. When styrene is copolymerized with ethylene glycol vinylglycidyl ether, the latter is less reactive. Il. 2. Tab. 3. Bibliography. 14 titles

Keywords: radical copolymerization; styrene; allyl glycidyl ether; vinylglycidyl ether of ethylene glycol.

RADICAL COPOLYMERIZATION OF STYRENE AND UNSATURATED GLYCIDYL ETHERS

M.A. Chernigovskaya, T.V. Raskulova

Angarsk State Technical Academy,

60, Chaikovskogo St., 665835, Angarsk, Irkutsk Region, 665835 Russia, [email protected]

The radical copolymerization of styrene and unsaturated glycidyl ethers (allyl glycidyl ether, ethylene glycol vinyl glycidyl ether) was examined in toluene solution. The reactivity ratios and parameters of copolymer microstructure were calculated. It was found that copolymer composition depends on unsaturated glycidyl ethers structure. Copolymers of styrene and allyl-glycidyl ether have an alternative structure. Ethylene glycol vinyl glycidyl ether has less reactivity than styrene in copolymerization. 2 figures. 3 tables. 14 sources.

Key words: radical copolymerization; styrene; allylglycidyl ether; ethylene glycol vinyl glycodyl ether. INTRODUCTION

One of the promising directions is the synthesis of copolymers with active functional chemistry of macromolecular compounds being onal groups. As monomers

for such syntheses, epoxy compounds and, in particular, unsaturated glycidyl ethers (UGEs) are of increasing interest. Copolymers containing EHE units in their composition are of interest for theoretical studies, since the simultaneous presence of the oxirane ring and oxygen atoms in the side chain in the EHE composition makes complexation effects possible.

On the other hand, such polymers provide the widest opportunity for targeted modification by carrying out polymer-analogous reactions on oxirane cycles and, therefore, open the way to obtaining materials, including composite ones, with a predetermined valuable set of properties.

The range of NGEs used in radical copolymerization reactions is quite wide, however, the most studied at present are methacrylic acid derivatives (for example, glycidyl methacrylate), allyl glycidyl ether (AGE), as well as vinyl glycol glycidyl ethers (for example, vinyl glycidyl ether ethylene glycol (EGE)). The most interesting as modifiers for industrial polymers are AGE and WGE, since due to their low reactivity they should be included in the composition of polymers in limited quantities, without changing the general complex of properties of the base polymer.

The traditional areas of use of these compounds in copolymerization processes are discussed in detail in the works. Recently, epoxy-containing copolymers are increasingly used for the manufacture of various nanomaterials and nanocomposites [for example, 5,6], as well as functional polymer composite materials. Therefore, the study of the processes of copolymerization of NGE, including AGE and WGE, with basic industrial monomers is of undoubted scientific interest.

The aim of this work was to study the binary radical copolymerization of styrene (St) with AGE and WGE.

EXPERIMENTAL PART

For the synthesis of copolymers, we used commercial St produced by OAO AZP (purity

99.8%) with constants: p = 0.906 g/mL, 1bp = 145°C, AGE (a product of ASSI) with constants: p = 0.962 g/mL, nip = 154°C, n20 = 1, 4330, and WGE obtained at the Institute of Chemical Chemistry of the Siberian Branch of the Russian Academy of Sciences, purified to chromatographic purity

99.9% with the following constants: p = 1.038

g/ml, ^un = 204 °C, = 1.4310.

The copolymerization was carried out in a toluene solution at a temperature of 60°C and a tenfold excess of the solvent. Azo-bis-isobutyric acid dinitrile was used as an initiator in an amount of 1% wt. The resulting copolymers were isolated by precipitation with isobutanol, purified by reprecipitation with isobutanol from acetone, and dried to constant weight.

The composition of the products obtained was determined from the data of elemental analysis (C, H), functional analysis (content of epoxy groups), and IR spectroscopy. Determination of the content of epoxy groups in the composition of copolymers was carried out by back titration with hydrochloric acid according to . The relative viscosity was determined for 1% solutions in cyclohexanone at 25°C.

THE DISCUSSION OF THE RESULTS

Depending on the composition of the initial mixture, the resulting copolymers are white solid powder or amorphous substances, readily soluble in polar solvents.

The fact that copolymerization proceeded in the studied systems was confirmed using turbidimetric titration data. For example, the turbidimetric titration curves for St–WGE copolymers (Fig. 1) exhibit one inflection, which indicates the formation of copolymers rather than a mixture of two homopolymers. A similar picture is observed for St-AGE copolymers.

In the IR spectra of the EGE, an absorption band is observed in the region of 1620–1650 cm–1, which is characteristic of a double bond. The presence of the oxirane cycle is confirmed by the presence of absorption bands in the spectrum in the following regions: 765 and 915 cm-1, related to asymmetric stretching vibrations of the epoxy ring; 1230 cm-1 related to the symmetrical stretching vibrations of the epoxy ring; 3060 cm-1, corresponding to vibrations of the methylene group in the epoxy ring.

In the IR spectra of the copolymer, there are no absorption bands characteristic of a double bond, which confirms the occurrence of the copolymerization process at the vinyl or allyl groups. In the absorption regions characteristic of the oxirane ring and alkyl groups, the spectra of the copolymers are identical to the spectra of the initial EHEs.

Experimental data obtained as a result of the study of copolymerization processes in the St - VGE and St - AGE systems are presented in Table. 1.

It was assumed that the investigated EGE

О 0.2 0.4 0.6 0.8 1.0

Precipitator volume, ml

Rice. Fig. 1. Dependence of the optical density of solutions of St-VGE copolymers on the volume of the added precipitant (methanol). The content of VGE in the original mixture (% mol.): 1 - 10; 2 - 25; 3 - 50

Table 1

General patterns of copolymerization St - NHE in a solution of toluene _ (DAK1% wt., 60 ° C, 2 h) __

No. Composition of the initial mixture, mol %. The composition of the copolymer, mol%. Exit, %

St OGE St OGE

St - AGE system

1 95 5 36,36 63,64 3,7

2 90 10 55,14 44,86 12,6

3 70 30 47,16 52,84 32,4

4 50 50 92,32 7,68 20,2

5 30 70 46,73 53,27 19,8

6 10 90 60,13 39,87 19,3

St - VGE system

1 90 10 91,98 8,02 68,5

2 75 25 79,93 20,07 56,7

3 50 50 67,95 32,05 46,2

4 25 75 55,08 44,92 38,1

5 10 90 46,45 53,55 32,5

have a lower reactivity in radical copolymerization than St. Such a picture is indeed observed for St-VGE copolymers. They are enriched in St units in the entire studied range of initial mixtures, while the content of HGE units in the composition of copolymers increases symbately with its amount in the monomer mixture (Table 1).

For copolymers St - AGE observed

a different picture. At any composition of the initial monomer mixture, the content of St and AGE units in the copolymers is almost the same and ranges from 40 to 64 mol %, which indicates the formation of products close to alternating (Table 1).

As an analysis of the literature data shows, AGE is characterized by the occurrence of processes of alternating copolymerization with sufficiently

table 2

General patterns of copolymerization of VC - NHE in a solution of toluene

(DAK 1 wt %, 60 °С, 2 h)

The composition of the initial mixture, mol%. The composition of the copolymer, mol%. Yield, % Viscosity [G|], dl/g

VK OGE VK OGE

VH system - AGE

95,0 5,0 96,79 3,21 3,19 0,20

90,0 10,0 93,92 6,08 2,88 0,15

85,0 15,0 87,92 10,58 2,56 0,08

73,7 26,3 76,19 23,81 2,69 0,04

30,1 69,9 44,69 55,31 2,48 0,04

VH - VGE system

95,0 5,0 95,55 4,45 3,78 0,29

90,0 10,0 92,44 7,56 3,45 0,26

80,0 20,0 88,44 11,56 3,01 0,22

75,0 25,0 78,79 21,21 2,91 0,17

25,0 75,0 36,62 63,38 2,23 0,13

a wide range of monomers [eg 11, 12]. This is explained by the formation of charge-transfer complexes between AGE and the second comonomer, in which AGE plays the role of a donor. However, the study of the binary radical copolymerization of AHE with VC carried out by the authors did not reveal the formation of alternating copolymers (Table 2).

The formation of alternating copolymers during the copolymerization of AGE with St can be associated with the formation of charge-transfer complexes between the epoxy group of AGE and the aromatic ring of styrene. The resulting complex then plays the role of "individual monomer" in the copolymerization, which leads to the production of products of alternating structure.

Product yields generally decrease

with an increase in the content of units of low-active monomers in the composition of copolymers (Table 1), which is due to an increase in the concentration of EHE in the initial mixture of comonomers. An increase in the concentration of an inactive monomer increases its content in the copolymer, but reduces the total chain growth rate and, consequently, reduces the yield of the product and its molecular weight. This reasoning confirms the values of the relative viscosity of solutions of copolymers (for example, St-AGE) and their dependence on the content of esters in the initial mixture (Fig. 2).

The calculation of the relative activity constants of the monomers (copolymerization constants) for the studied systems was carried out by different methods. Copolymerization constants of the system

Rice. 2 Dependence of the relative viscosity of copolymers St - AGE on the content of AGE in the initial mixture

Table 3

Copolymerization constants and average block lengths St ^^ _and NGE ^2) in copolymers_

System M1 m1 r Li L2

St-AGE system 0.70 0.47 r1 = 0.09 1 1

0.50 0.92 r2 = 0.05 21 1

0.75 0.20 n1 = 1.13 ± 0.09 n2 = 0.22 ± 0.02 10 1

System St - VGE 0.50 0.32 9 1

St-AGE was calculated on the basis of functional analysis data using the non-linear least squares method in the MathCAD 11 Enterprise Edition package, which makes it possible to carry out calculations using any sets of experimental data. The copolymerization constants for the St-WGE system were calculated by the standard Feynman-Ross and Kaelen-Tyudosh methods using the Mortimer and Tidwell experimental design method. The values of the constants of copolymerization are presented in table. 3. Based on the values of the copolymerization constants, the parameters of the microstructure of the copolymers were determined, which are also given in table. 3.

The obtained values of the copolymerization constants confirm the earlier conclusion about the different reactivity of NGE in the copolymerization processes with St. For the St-AGE system, the values of the calculated copolymerization constants are close to zero, which is typical for alternating copolymers. The calculation of the microstructure of these copolymers showed that almost strictly alternating products are obtained regardless of the composition of the initial mixture (Table 3).

The values of the relative activity constants for the copolymers St - VGE indicate a lower reactivity of WGE in radical copolymerization compared to St. VGE is present in the data structure of the co-

polymers only in the form of single units, and the length of the blocks of St units in copolymers naturally decreases with a decrease in the share of St in the initial mixture.

Thus, the structure of St and NGE copolymers can apparently be reflected by the following formula:

- // ZhPC. 1998 T. 71, No. 7. S. 1184-1188.

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4. Pokrovskaya M.A., Raskulova T.V. Copolymerization of allylglycidyl ether with styrene // Vestnik AGTA. 2011. No. 5. S. 87-89.

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6. Tan Chung-Sung, Kuo Ting-Wu. Synthesis of polycarbonate-silica nanocomposites from copolymeriza-tion of CO2 with allyl glycidyl ether, cyclohexene oxide, and sol-gel // J. Appl. Polym. sci. 2005. V. 98. No. 2. P. 750.

7. Formation of composites based on vinyl glycidyl ether of ethylene glycol and vinyl chloride / O.V. Lebedeva [et al.] // Plastic masses. 2013. No. 9. S. 35-39.

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11. Heatley F., Lovell P.A., McDonald J. NMR-studies of free-radical polymerization and copolymerization of monomers and polymers containing allyl groups // Eur. Polym. J. 2. 1993. V. 29, No. 2. R. 255.

12. Yu Qing-bo, Bai Ru-ke, Zhang Ming-Khi. Living radical copolymerization of allyl glycidyl ether with methyl acrylate in the presence of benzimidazole-1-carbodithionate // Anhui ligong daxue xuebao. Ziran kexue ban; J. Anhui Univ. sci. and Technol. Natur. sci. 2006. V. 26, No. 3. P. 56.

13. The effect of the penultimate link in the copolymerization of vinyl chloride and unsaturated glycidyl ethers / T.V. Raskulova [et al.] // High-molecular compounds A. 2000. V. 42, No. 5. P. 744-750.

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Fig.9. Dependence of the initial rate of copolymerization (1.4) and intrinsic viscosity (2.3) of the copolymer MAG with AA (1.2) and AG with AA (3.4) on the content of ionogenic monomer in the initial reaction mixture.

From fig. It also follows from Table 9 that the highest molecular weight samples of copolymers (judgment by the values of [h]) are obtained in monomer mixtures enriched in AA.

The most likely reason for the observed decrease in the chain growth rate constant with an increase in the concentration of the ionic comonomer is that the concentration of strongly hydrated acrylate and methacrylate anions in relatively hydrophobic uncharged coils of macroradicals is lower than their average concentration in solution, which is indirectly confirmed by the decrease in the reduced viscosity of the copolymer solution with an increase in the content of AG and MAG units.

The decrease in [h] is more logically associated with the structuring effect of AG and MAG ions on water molecules, which leads to a decrease in volume effects, i.e. the quality of water as a solvent for PAM is deteriorating.

Thus, the observed features and differences in the series of monomers under consideration are explained by the complex nature of the contributions of various physicochemical processes that determine the course of the copolymerization reaction of acrylamide with guanidine-containing monomers of the acrylic series. At the same time, the main contribution to the change in the effective reactivity of polymerizing particles is made by associative interactions between guanidine and carboxyl groups (both intra- and intermolecular) and the structural organization of the corresponding monomers and polymers during copolymerization.

3.2 Radical copolymerization of guanidine monomaleate with acrylate and methacrylate guanidine in aqueous media

Ion-exchange sorbents, coagulants and flocculants, biocides, separating membranes, soil structurators, models of biopolymers, polymer carriers of various kinds of functional fragments - this is by no means a complete list of the practical applications of synthetic polyelectrolytes. One of the most common and promising ways to obtain polyelectrolytes is the radical polymerization and copolymerization of monomers ionized in aqueous solutions.

In this work, we consider the synthesis of a biocidal copolymer based on guanidine acrylate and methacrylate with guanidine monomaleate. Radical homopolymerization and copolymerization of guanidine-containing compounds is the object of research by many authors, mainly in connection with the possibility of obtaining polymeric materials with a complex of specific properties, including biocidal ones. However, there is little information in the literature regarding the study of the processes of radical copolymerization of ionogenic monomers containing the same functional groups. In this regard, the study of the processes of copolymerization of guanidine-containing ionogenic monomers seems to us to be very relevant. It is known that due to the symmetry of the structure, spatial factors and the high positive polarity of the vinyl group, maleates do not form homopolymers in the presence of radical initiators. The experimental results obtained in this work also showed that the homopolymerization of guanidine monomaleate (MMG) under the studied conditions is difficult. So, for example, the degree of conversion of the MMG monomer into a polymer under the conditions ([MMH] = 2 mol × l -1; 60 ° C; [PSA] = 5 × 10 -3 mol × l -1; H 2 O; polymerization time 72 hours) is about 3% ([η] = 0.03 dl×g–1). All these facts indicate a significant contribution of the above factors to the process of homopolymerization of the system studied by us.

At the same time, it is important to note that when studying the reaction of radical copolymerization of MMG with guanidine methacrylate (MAG), a number of copolymers of various compositions with sufficiently high intrinsic viscosities and, consequently, molecular weights were obtained.

Radical copolymerization was studied in aqueous (bidistillate), water–methanol, and methanol solutions; the radical initiators were ammonium persulfate (APS) and azobisisobutyric acid dinitrile (AAB) ([I] = 10–2–10–3 mol × l – 1) in the temperature range of 20 - 60 °C.

It was previously established that polymerization does not occur in the absence of an initiator.

The prepared reaction mixture was degassed in ampoules in a vacuum unit (10–3 mm Hg), after which the ampoules were sealed off and placed in a thermostat. In the case of decomposition of the initiator at low temperatures (20°C, UV), the reaction solution was transferred into quartz cuvettes (in a vacuum).

Copolymerization was carried out to various degrees of conversion (the study of polymerization and copolymerization to high degrees of conversion can give results important in practical terms), and the following regularities were revealed. In all cases, the formation of copolymers enriched in AG and MAG units compared to the initial mixture of comonomers is observed (Table 11), which indicates a higher reactivity of MAG in chain propagation reactions.

Table 11

Dependence of the composition of the copolymer on the initial composition of the reaction solution during the copolymerization of AG (MAG) (M 1) and MMG (M 2) M 1 + M 2 ] = 2.00 mol/l; [PSA]= 5 10 -3 mol l -1; H 2 O; 60 °C.

No. p / p	Initial comonomers M 1:M 2, mol.%	Copolymers a M 1:M 2, (mol. %)/ [h] b, dl/g
AG-MMG		MAG-MMG
1	Initial comonomers M 1:M 2, mol.%	40:60	90:10	0,35	75:25	0,15
2	50:50	95:5	0,55	68:32	0,20
3	70:30	75:25	0,88	90:10	0,27
4	80:20	97:3	0,93	96:4	0,41
5	90:10	98:2	0,98	98:2	0,53

Note. a) Determined by NMR 1 H and IR spectroscopy.

b) Determined at 30 °C in 1N NaCl aqueous solution.

Based on studies of the radical copolymerization of MAG and MMG, it can be concluded that copolymerization occurs only with an excess of guanidine methacrylate. If there is an excess of guanidine monomaleate, neither copolymerization nor homopolymerization of guanidine methacrylate is observed.

The composition of the synthesized polymer products was confirmed by 1H NMR and IR spectroscopy.

The predominant contribution of the steric factor to the reactivity of guanidine monomaleate in the copolymerization reaction with AG and MAG is confirmed by the values of the copolymerization constants, which are presented in Table.

Table 12

The value of effective copolymerization constants in systems

AG (MAG) (M 1) - MMG (M 2)

([M] sum \u003d 2 mol × l -1; [PSA] \u003d 5 × 10 -3 mol × l -1; 60 ° C, H 2 O)

3.3 Physicochemical properties of synthesized copolymers

1H NMR and IR spectroscopy studies of the polymer compounds synthesized in this work confirmed the proposed structure of the objects of study. The study of the 1H NMR spectra of the synthesized copolymers made it possible to determine the comonomer composition by analyzing the integral intensities of various signals.

3.3.1 IR spectral studies of synthesized copolymers

The analysis of the IR spectral characteristics was carried out by comparing the spectra of the monomeric guanide-containing salt and acrylamide, taken as models, as well as by comparing the spectra of polymeric compounds, which were supposed to confirm the corresponding changes in the spectra upon passing from monomers to copolymers. IR spectra of all compounds were recorded in solid form in KBr pellets.

IR spectral characteristics of the initial guanidine-containing monomers are given in table. 13.

Table 13

IR spectral data of acrylic derivatives of guanidine a

a The position of the peaks of the corresponding signals is given in cm–1.

In the study of the IR spectra of copolymers AG and MAG and AA, it was found that the resulting copolymers contain absorption bands characteristic of bending vibrations of the N-H bond in acrylamide at 1665 cm–1 and intense bands of skeletal bending vibrations at the CH 3 -C= site of methacrylate guanidine at 1470 and 1380 cm -1 . Moreover, depending on the composition of the copolymer, the intensity of these bands varies. Due to the closeness of the structures of AA and AG, the characteristic bands of the comonomers overlap and the IR spectra for this pair are not sufficiently informative. The spectra also contain an absorption band of the carboxylate ion (1560–1520 cm–1). The bands of stretching vibrations of N–H bonds are strongly shifted towards long wavelengths (3130 and 3430 cm–1) and are rather intense. The spectrum of the copolymer contains an intense broad band with a maximum at 1648 cm–1, which, of course, is distorted by the absorption of deformation vibrations of water in this region, but its intensity and the presence of several kinks on the shoulders indicate that the N= bond is also present in this compound. C and NH 2 group.