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DOI: 10.14529/chem160103
SYNTHESIS OF BUTYL METHACRYLATE COPOLYMERS WITH THE USE OF COMPENSATE POLYMERIZATION METHOD
L.L. Semenycheva, [email protected] E.V. Geraskina, [email protected] Yu.O. Matkivskaya, [email protected] A.A. Moikin, [email protected]
Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russian Federation
Butyl methacrylate copolymers with vinyl alkyl ethers and styrene have been obtained by compensate polymerization method. The properties of copolymers have been determined with the use of gel-penetration chromatography, IR- and 1H NMR-spectroscopy.
Keywords: butyl methacrylate, vinyl butyl ether, vinyl isobutyl ether, structurally uniform polymers, molecular weight characteristics.
Introduction
The most commonly encountered industrial method to obtain copolymers is by radical initiation. In spite of diversity of the modern molecular design methods, such as complex-radical processes, pseudo-living radical polymerization, etc. [1-3], the problem of characteristics modification for polymer materials using development of copolymer synthesis without additives, with classical radical initiators, is of as great importance as before. One of such methods is compensate copolymerization, which involves fractional introduction of one of the monomers into the reaction sphere. In this way it is possible to obtain copolymers differing in composition from the monomer mixture, therefore, possessing new characteristic features. In the series of papers [4-7] the results were presented, concerning application of the compensate copolymerization method to obtain structurally uniform copolymers of vinyl alkyl ethers (VAE) with alkyl(meth)acrylates (AMA). The advantages of the chosen method were shown compared to synthesis from a monomer mixture, enabling the synthesis of gradient copolymers. Butyl acrylate (BA) was mostly used as the model monomer couple in order to study the synthesis features.
The aim of the present paper is the investigation of compensate radical copolymerization of vinyl monomers demonstrated by the example of monomer couples including butyl methacrylate (BMA), specifically, BMA - vinyl butyl ether (VBE), BMA - vinyl isobutyl ether (ViBE), BMA - styrene.
Experimental
Commercial reagents were used throughout.
In order to determine relative reactivity of comonomers BMA-VBE and BMA-ViBE the synthesis of copolymers from a monomer mixture was performed in vacuumed ampoules. During the experiment monomer mixtures with various ratios were used: from 5 to 95 % (mol) VAE. The copolymers were isolated at 5-7 % conversion. Relative reactivities were calculated by Kelen-Tudos method [8].
In order to synthesize copolymers in ampoules the exact amounts of monomers and initiator were placed into glass ampoules, freed from oxygen by freezing the reaction mixture in liquid nitrogen and pumping out to residual pressure < 1.3 Pa. The ampoules were glass-sealed, then polymerization was carried out at strictly determined temperature. For that an ampoule was placed into a thermostat for preset time, after which the ampoule was taken out and frozen in liquid nitrogen to stop polymerization. The copolymer was isolated by recrystallization from solution [4]. Monomer conversion was gravimetr-ically determined.
The synthesis of copolymers by compensate polymerization method was performed in a four-necked flask with a reflux condenser, a paddle-type agitator, a thermocouple, and an outlet for reagent injection, placed in a thermostat. An exactly weighed sample of one monomer or its solution was placed into the flask, the mixture was brought to boil while stirring. Through the outlet for reagent injection a solution of exactly weighed sample of another monomer was measured in doses with the use of a dropping funnel. After preset synthesis time the flask was cooled in water bath (40 °C). (Unreacted mono-
mers were pumped out at low pressure (to 0.5 mm of mercury). Under vacuumization conditions the polymer was dried in the flask to constant weight at T=20-25 °C.
Molar masses and molecular mass distribution of the copolymers were determined at the set of 5 styrogel columns with pore diameters 105, 3-104, 104, 103, and 250 A (Waters, USA). Detection was performed by differential refractometer R-403 and UV-detector UV-101 (Waters). Tetrahydrofuran was used as the eluent. Calibration was carried out with the use of narrow-dispersed polystyrene (PST) standards [9].
The calculation of molar masses for styrene copolymers was carried out in conformity with PST standards, while for AMA copolymers it was accomplished by the standard formula (1) using Kuhn-Mark-Houwink constants for AMA and styrene.
logM(copolymer) = 1 + a(PST) x logM (PST) +-1-x log K(PST) (i)
1 + a(PAMA) v ' 1 + a(PAMA) K (PAMA)
IR spectra of the synthesized copolymers were recorded on the Fourier-transform IR spectrometer Shimadzu FTIR-8400S in KBr cuvettes with pathlength 0.26 mm in chloroform solution. The range of wavenumbers was 5500-550 cm-1, determination error did not exceed ±0.05 cm-1. The copolymer composition was determined with the use of calibrating curve by characteristic peak area. The analytical bands were the following: the band at 1727 cm-1 for carbonyl group (acrylate fraction); the band at 1100 cm-1 for C-O-C group of ether (VAE fraction); the band at 1600 cm-1 for C=C vibrations of styrene aromatic ring (styrene fraction).
1H NMR spectra were recorded on the Agilent DD2 400 spectrometer (solutions in CDCl3), at operating frequency 400 MHz. Chemical shifts are given in ppm in relation to the solvent residual signal (chloroform: 7.26 ppm). All spectra are recorded at temperature 25 °C.
Results and Discussion
According to the radical copolymerization theory [10], the copolymer composition at radical initiation is determined by relative reactivity of monomers. In the case of greatly different relative reactivities- which is true in the case of AMA and VAE copolymerization - high rate of polymer formation from a monomer mixture is observed at the excess of the reactive monomer, and the formed copolymer is richer in the reactive monomer. The method using uniform introduction of the reactive monomer (compensate copolymerization) at any moment provides conditions of yielding a polymer with greater VAE content from the couple "reactive monomer - non-reactive monomer": due to its high reactivity the introduced AMA leaves the reaction sphere, forming copolymerization product, while VAE is in significant excess again. The formed copolymer, e.g. BA-VBE [4, 5, 7], has high degree of structural uniformity, which is ensured, among other things, by VAE inability for homopolymerization at the radical initiation conditions. It has been considered interesting to obtain copolymer of BMA and VAE at the similar conditions.
For monomer couples BMA-VBE and BMA-ViBE the values of relative reactivities are not described in the literature, it was necessary to find them experimentally. Table 1 shows the ratios of monomer mixtures BMA (M1) with VBE and ViBE (M2), as well as copolymers (m) obtained from the given monomer mixture at low conversion.
Table 1
Data on copolymer composition in relation to monomer mixture composition for BMA-VBE and BMA-ViBE
[M] [М] [Ш2] [mi]
1 2 3 4
ViBE-BMA
5 95 0.9 99.1
20 80 2.2 97.8
35 65 5.1 94.9
50 50 11.4 88.6
60 40 14.2 85.8
Table 1 (end)
1 2 3 4
70 30 22.1 77.9
80 20 26.8 73.2
90 10 33.1 66.9
95 5 35.2 64.8
VBE-B ¡MA
5 95 1.1 98.9
20 80 5.7 94.3
35 65 12.0 88.0
50 50 14.7 85.3
60 40 22.3 77.7
70 30 27.4 72.6
80 20 35.2 64.8
90 10 40.6 59.4
95 5 42.7 57.3
The calculation has given values for comonomers BMA-ViBE r1= 7.8 and r2~ 0; BMA-VBE r1= 4.1 and r2~ 0. If the obtained values are compared to those for BA (BA-ViBE r1= 5.2 and r2~ 0; BA-VBE r1= 1.43 and r2~ 0), it is obvious that the tendency of BMA for addition of its monomer is much higher than such of BA. This difference cannot but be reflected in experimental data at copolime-rization. Indeed, compensate copolymerization of BMA with VAE (at comparable conditions for BA) leads to lower conversion, and the formed copolymer is characterized by slightly higher acrylate content (Table 2, rows 1, 2 and 4, 5, respectively). Nevertheless, there are strong grounds for affirmation that -unlike the copolymerization from a monomer mixture, leading to structurally nonuniform gradient copolymer [10] - formation of predominantly structurally uniform copolymer, nearing equimolar composition, takes place.
Table 2
Composition of copolymers synthesized by compensate polymerization
AMA Second AMA dosing Copolymer yield in reactive monomer, % Content of acrylate units, mol %, according to data
monomer time, min gravimetry IR spectroscopy 1H NMR spectroscopy
1 VBE 74 57 54 56
2 BMA ViBE 53 68 68 65
3 styrene 20-30 ~50 - 39 41
4 BA VBE* ~100 52 52 51
5 ViBE ~100 64 70 61
* Data [4].
In the case of the couple BMA-styrene, as well as BA-styrene, as opposed to compositions BA-VAE, BMA-VAE, both monomers have similar relative reactivities: BMA-styrene 0.64-0.54 [10] and BA-styrene 0.20-0.88 [11]. At initial monomer mole ratio 1:1 the polymerization proceeds at high rate due to gel effect, at that the copolymer composition at deep conversion stages is practically the same as the initial one, and by the example of BA-styrene it has been shown that mostly the structurally uniform copolymer is formed [11]. In the present study compensate copolymerization method has been used in the first stage of BMA-styrene copolymerization (Table 2), lest the polymerized mixture would be intensively heated due to gel effect. Toluene has been chosen with the intent of dissolving the formed copolymer; heptane has been used in order to maintain the synthesis temperature close to the VBE boiling point, for the purpose of nearing the polymerization conditions to the previous studies, carried out at the VBE boiling point. (VBE Tbp = 94 °C; heptane Tbp = 94 °C; it does not form any azeotrope mixture with
toluene.) In the dosing time ~30 min the conversion amounts to ~8 %, and after the following stirring during 2.5 h the copolymerization proceeds to conversion ~50 %, at that the polymerization process runs smoothly without gel effect. It can be seen (Table 2, row 3) that the formed copolymer is near to equi-molar composition.
Table 3
Data on composition of acrylate and styrene copolymers and their molecular mass characteristics
No. Monomer in the reaction mixture Monomer in the doser Content of acrylate units, mol %, according to data Mn, Da Mw, Da Ww/Mn
IR NMR
1 BA Styrene 48 47 15000 28300 1.9
2 Styrene BA 53 54 13400 29600 2.2
3 Styrene BMA 39 40 21200 54400 2.6
4 Styrene EHA* 35 - 18100 37900 2.1
*The sample is shown for comparison, EHA - ethylhexyl acrylate.
The study of the molecular mass characteristics of the newly synthesized copolymers BMA-VAE and BMA-styrene has shown that curves of molecular mass distribution are unimodal for all samples. As in the case of BA-VAE copolymers, molar masses are greater for BMA-ViBE than for BMA-VBE (Table 3, rows 1, 2 and 4, 5, respectively).
Table 4
Molecular mass characteristics of the copolymers obtained by compensate polymerization method
No. Monomer couple Mn, kDa Mw, kDa Mw/Mn
1 BMA-VBE 35 77 2.2
2 BMA-ViBE 38 130 2.8
3 BMA-styrene 21 54 2.6
4 BA-VBE 18 55 2.9
5 BA-ViBE 21 93 4.3
Conclusions
Butyl methacrylate copolymers with vinyl alkyl ethers and styrene have been obtained by compensate polymerization method. The properties of copolymers have been characterized with the use of gelpenetration chromatography, IR- and :H NMR-spectroscopy. The values of relative reactivity have been found for the couples BMA-VBE and BMA-ViBE.
Acknowledgments
The research was supported by the Ministry of Education and Science of the Russian Federation (assignment No. 2014/134, agreement dated 27 August 2013 No. 02.B.49.21.0003 between the Ministry and UNN) with the use of equipment of the center "New materials and resource-saving technologies" (project RFMEFI59414X0005).
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Received 12 November 2015
УДК 54.057+54.062 DOI: 10.14529/chem160103
СИНТЕЗ СОПОЛИМЕРОВ БУТИЛМЕТАКРИЛАТА С ИСПОЛЬЗОВАНИЕМ КОМПЕНСАЦИОННОГО СПОСОБА
Л.Л. Семенычева, Е.В. Гераськина, Ю.О. Маткивская, А.А. Мойкин
Нижегородский государственный университет им. Н.И. Лобачевского, г. Нижний Новгород
Сополимеры бутилметакрилата с винилалкиловыми эфирами и стиролом получены с использованием компенсационного способа. Свойства сополимеров определены с использованием методов ГПХ, ИК- и :Н ЯМР-спектроскопии.
Ключевые слова: бутилметакрилат. винилбутиловый эфир, винилизобутиловый эфир, композиционно-однородные сополимеры, молекулярно-массовые характеристики.
Литература
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2. Lena, F. Transition Metal Catalysts for Controlled Radical Polymerization /F. Lena, K. Matyjaszewski // Progress in Polymer Science. - 2010. - V. 35. - Р. 959-1021.
3. Rzaev, Z.M.O. Complex-Radical Alternating Copolymerization / Z.M.O. Rzaev // Prog. Polym. Sci. - 2000. - V. 25. - P. 163-217.
4. Семенычева, Л.Л. Сополимеры бутилакрилата с винилалкиловыми эфирами как загущающие присадки к маслам / Л.Л. Семенычева, Е.И. Богатова, В.В. Винс // Журнал прикладной химии. - 2008. - Т. 81, вып. 9. - С. 1563-1566.
5. Семенычева, Л.Л. Особенности синтеза сополимера бутилакрилата с винил-н-бутиловым эфиром для получения эффективной загущающейприсадки к маслам / Л.Л. Семенычева,
B.В. Винс, Е.И. Богатова и др. // Журнал прикладной химии. - 2009. - Т. 82, вып. 9. - С. 15421545.
6. Гераськина, Е.В. Модификаторы вязкости на основе сополимеров винилизобутилового эфира для смазочных масел. / Е.В. Гераськина, Ю.О. Маткивская, Е.П.Чухманов и др. // Журнал прикладной химии. - 2014. - Т. 87, вып. 11. - С. 1609-1614.
7. Семенычева, Л.Л. Влияние молекулярной массы на свойства сополимеров винилбутилово-го эфира и алкил(мет)акрилатов как загущающих присадок к нефтяным маслам. / Л.Л. Семенычева, Е.В. Гераськина, О.А. Казанцев и др.// Журнал прикладной химии. - 2014. - Т. 87, вып. 2. -
C. 244-249.
8. Evaluation of High Conversion Copolymerization Data by a Linear Graphical Method / F. Tudos, Т. Kelen, Т. Foldes-Berezhnykh et al. // React. Kinet. Catal. Letter. - 1975. - V. 2, N. 4. - P. 439-447.
9. Determination of Free-Radical Propagation Rate Coefficients of Butyl, 2-Ethylhexyl, and Do-decyl Acrylates by Pulsed-Laser Polymerization / S. Beuermann, D.A. Paquet, J.H. McMinn et al. // Macromol. -1996. - V. 29. - P. 4206-4215.
10. Ham, G.E. Copolymerization /G.E. Ham. - N.Y.: Interscience Publishers, 1964. - 939 p.
11. Ziaee, F. Kinetic Investigation and Characterization of Styrene-Butyl Acrylate Solution Copolymerization / F.Ziaee, M.Nekoomanesh //Iranian Polymer Journal. -1999.-V.8, N.2.-P. 83-90.
Семенычева Людмила Леонидовна - зав. лаборатории нефтехимии НИИ химии, Нижегородский государственный университет им. Н.И. Лобачевского. 603950, г. Нижний Новгород, пр. им. Ю.А. Гагарина, 23. E-mail: [email protected]
Гераськина Евгения Викторовна - аспирант лаборатории нефтехимии НИИ химии, Нижегородский государственный университет им. Н.И. Лобачевского. 603950, г. Нижний Новгород, пр. им. Ю.А. Гагарина, 23. E-mail: [email protected]
Маткивская Юлия Олеговна - аспирант лаборатории нефтехимии НИИ химии, Нижегородский государственный университет им. Н.И. Лобачевского. 603950, г. Нижний Новгород, пр. им. Ю.А. Гагарина, 23. E-mail: [email protected]
Мойкин Алексей Анатольевич - докторант лаборатории нефтехимии НИИ химии Нижегородский государственный университет им. Н.И. Лобачевского. 603950, г. Нижний Новгород, пр. им. Ю.А. Гагарина, 23. E-mail: [email protected]
ОБРАЗЕЦ ЦИТИРОВАНИЯ
Synthesis of butyl methacrylate copolymers with the use of compensate polymerization method / L.L. Semenycheva, E.V. Geraskina, Yu.O. Matkivskaya, A.A. Moikin // Вестник ЮУрГУ. Серия «Химия». - 2016. - Т. 8, № 1. - С. 2025. DOI: 10.14529/chem160103
Поступила в редакцию 12 ноября 2015 г.
FOR CITATION
Semenycheva L.L., Geraskina E.V., Matkivskaya Yu.O., Moikin A.A. Synthesis of butyl methacrylate copolymers with the use of compensate polymerization method. Bulletin of the South Ural State University. Ser. Chemistry. 2016, vol. 8, no. 1, pp. 20-25. DOI: 10.14529/chem160103
