Copolymerization of the poly(N,N-dimethyl-N,N-diallylammonium chloride) macromonomer with acrylamide

Article abstract of DOI:10.1007/s11172-007-0085-1

Copolymers of the poly(N,N-dimethyl-N,N-diallylammonium chloride) macromonomer (1′) with acrylamide (2) with a high content of cationic groups (up to 50%) were synthesized. The relative activities r _1′ and r ₂ were calculated. The relative activities calculated by the Kelen-Tudos (r _1′ = 0.057±0.009, r ₂ = 1.57±0.12) and Feynman-Ross (r _1′ = 0.055±0.011, r ₂ = 1.58±0.14) methods are in accordance. The intrinsic viscosity and the yield of copolymers were found to decrease with an increase in the molar fraction of macromonomer 1′ in the monomer mixture.

Full text of DOI:10.1007/s11172-007-0085-1

Russian Chemical Bulletin, International Edition, Vol. 56, No. 3, pp. 535—539, March, 2007
535
Copolymerization of the poly(N,NꢀdimethylꢀN,Nꢀdiallylammonium
chloride) macromonomer with acrylamide
a
b
c
O. V. Kalyazina,a T. G. Murzabekova, T. F. Lelyukh, and I. A. Gritskova
ꢀ
aState Research Institute of Genetics and Selection of Industrial Microorganisms,
1 1ꢀi Dorozhnyi pr., 117545 Moscow, Russian Federation.
Fax: +7 (495) 315 5133. Eꢀmail: kalyazina@yandex.ru
bNovosibirsk Plant of Chemical Concentrates,
95 ul. Bogdana Khmel´nitskogo, 630110 Novosibirsk, Russian Federation.
Fax: +7 (383) 271 3302
cM. V. Lomonosov Moscow State Academy of Fine Chemical Technology,
86 prosp. Vernadskogo, 119571 Moscow, Russian Federation
Copolymers of the poly(N,NꢀdimethylꢀN,Nꢀdiallylammonium chloride) macromonoꢀ
mer (1´) with acrylamide (2) with a high content of cationic groups (up to 50%) were syntheꢀ
sized. The relative activities r1´ and r2 were calculated. The relative activities calculated by the
Kelen—Tudos (r1´ = 0.057 0.009, r2 = 1.57 0.12) and Feynman—Ross (r1´ = 0.055 0.011,
r2 = 1.58 0.14) methods are in accordance. The intrinsic viscosity and the yield of copolymers
were found to decrease with an increase in the molar fraction of macromonomer 1´ in the
monomer mixture.
Key words: cationic polyelectrolytes, copolymerization, waterꢀsoluble polymers.
In a series of materials used presently in the petroꢀ
leum, paper, and textile industries and in processes of
sewage and water treatment, copolymers based on acrylꢀ
amides are most popular.1—9 Among them, a special role
belongs to copolymers containing units of diallylic quaꢀ
ternary ammonium compounds and bearing a positive
charge directly in the main chain of the copolymer. This
provides a high charge density and favorably distinguishes
these substances from other copolymers of cationic naꢀ
ture, whose charge is located on branches of the main
chain.
Different reactivities of the vinylic monomer of acrylꢀ
amide and diallylic quaternary ammonium salts do not
allow one to prepare copolymers with a high content of
the latter.
At the same time, it was found10 that the homoꢀ
polymerization of a representative diallylic ammonium
compound, N,NꢀdimethylꢀN,Nꢀdiallylammonium chloꢀ
ride (1), gives a polymer containing the terminal vinylic
double bond (Scheme 1) due to efficient chain transfer to
the monomer. These bonds were detected by the radioꢀ
chemical11 and 13C NMR techniques.10
Scheme 1
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 515—518, March, 2007.
1066ꢀ5285/07/5603ꢀ0535 © 2007 Springer Science+Business Media, Inc.

536
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 3, March, 2007
Kalyazina et al.
13С NMR spectra, the delay time between two pulse sequences
was 3 and 5 s, respectively; the scan number was 64 and 20 000,
respectively.
Chemical shifts were measured relative to the external stanꢀ
dard Me4Si, and the accuracy of measurements of chemical
shifts was 0.05 ppm. The spectra were processed using the
Bruker 1D WINNMR program.
The copolymer composition was determined by the direct
titration of dilute solutions of the copolymers with a 0.001 N
titrated solution of sodium polyethylenesulfonate. A 1% alcoꢀ
holic solution of Toluidine Blue was used as the indicator. Titraꢀ
tion was carried out until the color changed from blue to redꢀ
violet. Each solution was titrated at least 3 times.
The content of the cationic comonomer (wt.%) was calcuꢀ
lated by the formula
Taking into account these data, we assumed that the
terminal double bond of poly(N,NꢀdimethylꢀN,Nꢀdiallylꢀ
ammonium chloride) (1´) can be involved in copolymerꢀ
ization with monomers of different nature. In particular,
hydrogels were obtained12 directly from compound 1´ by
radical crossꢀlinking with the bifunctional crossꢀlinking
agent N,N´ꢀmethylenebisacrylamide at the terminal
double bonds of the macromolecules. This seems promisꢀ
ing for the development of new polymers containing posiꢀ
tively charged groups and possessing unique properties.
In the present work, we check this assumption.
Experimental
x = M1C1V1/g.
Poly(N,NꢀdimethylꢀN,Nꢀdiallylammonium chloride) (1´)
was prepared according to a procedure13 from compound 1 synꢀ
thesized from dimethylamine (33% aqueous solution, highꢀpuꢀ
rity grade) and allyl chloride (dried with calcium chloride and
Here М1 is the molecular weight of the cationic comonomer;
С1 is the molar concentration of the titrant (mol L–1); V1 is the
titrant volume in the point of equivalence (L); g is the weight of
the copolymer in the volume of the solution taken for titraꢀ
tion (g)
20
distilled over CaCl2), b.p. 45 °С, nD = 1.4100. Found (%):
C, 59.35; H, 10.0; Cl, 22.04; N, 8.61. C8H16ClN. Calculated (%):
С, 59.43; Н, 9.98; Cl, 21.93; N, 8.66. Acrylamide (2, technical
product) was twice recrystallized from acetone and dried in vacuo
above Р2О5 to a constant weight (m.p. 84 °С). The initiators
were hydrogen peroxide (50% aqueous solution, analytical puꢀ
rity grade) and ammonium persulfate (NH4)2S2O8 (analytical
purity grade, recrystallized from bidistilled water and dried
in vacuo to a constant weight). The solvents were acetone and
methanol (analytical purity grade). Sodium chloride (reagent
grade) was used to prepare solutions for determination of intrinꢀ
sic viscosity.
g = mV2/V3,
where m is the weight of the copolymer weighed sample (g); V2 is
the volume of the copolymer solution (mL); V3 is the volume of
the volumetric flask (mL).
The copolymer composition was recalculated from wt.% to
mol.% by the equations
,
,
Polymer 1´ was synthesized by the radical polymerization of
compound 1 in an aqueous solution under anaerobic conditions
(2 mol L–1, Т = 60 °С, ammonium persulfate as the initiator
(1•10–3 mol L–1), polymerization duration 7 h). The intrinsic
viscosity of synthesized polymer 1´ was 0.3 dL g–1
.
where x1 and x2 are the weight concentrations of the comonoꢀ
mers (wt.%); m1 and m2 are the molar concentrations of the
comonomers (mol.%); М1 and М2 are the molecular weights of
the monomers М1 and М2.
The copolymer composition was determined at the converꢀ
sion of the comonomers at most 5%.
Copolymerization of 1´ with acrylamide (2) was carried out
in an aqueous medium at different ratios of the comonomers
(10 : 90, 15 : 85, 40 : 60, 60 : 40, 80 : 20, and 90 : 10). The total
concentration of the comonomers was 0.7 mol L–1, the initiator
(Н2О2) concentration was 0.5% (0.147 mol L–1), Т = 40 °С,
and the duration of the reaction was 20 h for experiments on
determination of the yields and intrinsic viscosities of the coꢀ
polymers formed and 1.5 h for experiments on determination of
the copolymer composition. Sealed ampules were placed in
a thermostat. After the end of the reaction, the contents of the
ampules were transferred into waterꢀfree cooled acetone, and
the copolymer was isolated as a white precipitate. The product
was twice washed with anhydrous acetone and treated with
methanol to dissolve unreacted compound 1´. Then the product
was twice washed with methanol again and dried to a constant
weight in a vacuum drying oven.
The intrinsic viscosity of solutions of polymers was meaꢀ
sured at 30 °С on an Ubellohde viscosimeter using a 1 М soluꢀ
tion of NaCl as the solvent.
The 1H and 13С NMR spectra of solutions of the polymers in
deuterated water were recorded at room temperature on a Bruker
MSLꢀ300 spectrometer with working frequencies of 300 and
75.15 MHz, respectively. 13С NMR spectra were obtained with
spinꢀspin 13С—1H decoupling. For recording the 1H and
Results and Discussion
The initial monomer 1 and the corresponding polyꢀ
mer 1´ were preliminarily synthesized. The structures and
compositions of the monomer and polymer were conꢀ
firmed by 1Н and 13С NMR spectroscopy. The 13С NMR
spectrum of sample 1´ contains lowꢀintensity signals with
δ 126.40 and 129.90 (Н2С=СН). The 1Н NMR spectrum
also exhibits signals of the terminal Н2С=СН groups at δ
5.65—6.25. This indicates that macromolecules 1´, which
are introduced in copolymerization with acrylamide 2,
contain the terminal double bond.
The synthesized copolymers were studied by 13С NMR
spectroscopy. The chemical shifts in the 13С NMR specꢀ
tra of the copolymers of 1´ with 2 are given below.

Copolymerization of polyammonium salt
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 3, March, 2007
537
The following conclusion is a result of comparison of
these results with the data on the copolymerization
of monomer 1 with compound 2 (r1 = 0.06 0.03,
r2 = 6.4 0.4).16 Although the copolymerization of macroꢀ
monomer 1´ with compound 2 involves two vinylic
comonomers, unlike that between monomer 1 and comꢀ
pound 2 involving the diallylic and vinylic comonomers,
macromonomer 1´ (as well as 1) is much less reactive
than 2. This is also caused, most likely, by steric hindrance,
because macromolecules 1´ are bulky. The ratios of reacꢀ
tivities r2/r1´ = 27.5 (according to the Kellen—Tudos
method) and r2/r1 = 106.7 indicate that macromonomer 1´
is more reactive than 1 in the copolymerization with 2.
In addition, according to the obtained data, both comꢀ
pound 2 and macromonomer 1´ are considerably easier
added to monomeric molecules 2 than to 1´. In this case,
the polymer contains excess units of 2 even at a higher
content of macromonomer 1´ in the initial mixture. Nevꢀ
ertheless, since the macromonomer itself is a ready block
of the cationic monomeric unit, copolymers with a high
content of cationic groups can be obtained (see Table 1),
which is confirmed by the data on titration of solutions of
the synthesized copolymers.
Returning to the important role of the structure of
macromolecules 1´ introduced into the copolymerization
reaction, it should be mentioned that macromolecules 1´
contain groups with the tertiary N atom due to partial
dequaternization. The presence of an insignificant amount
of these groups in 1´ has been proved earlier14 by NMR
spectroscopy. Therefore, under our conditions, hydrogen
peroxide decomposition is caused, most likely, by the
redox reaction between its molecules and the groups in
molecules 1´ containing the tertiary N atom.
Atom
1, 1´ 2, 2´ 3, 3´ 4, 4´
5
6
7
δ
70.35 38.25 26.45 52.45, 49.05 43.20 177.90
54.15
No signals indicating the terminal double bond in macꢀ
romolecules 1´ were observed in the 13С NMR spectra of
the copolymers, whereas these signals were observed in
1
the spectra of homopolymer 1´. The Н NMR spectra of
the copolymer samples also indicate the absence of termiꢀ
nal double bonds (no signals in the region of δ 5.65—6.25).
Thus, we can conclude that copolymerization involves
the terminal double bonds. A special series of experiments
performed under the same conditions as the copolymerꢀ
ization of macromonomer 1´ with compound 2 showed
no homopolymerization of macromolecules 1´ to occur
under these conditions. Therefore, the spectral data conꢀ
firm the formation of copolymers of macromonomer 1´
with compound 2.
To reveal the dependence of the composition of the
copolymers on the molar ratio of the comonomers and to
calculate the copolymerization constants, we carried out
the copolymerization of macromonomer 1´ with comꢀ
pound 2 at different ratios of the comonomers in the
initial reaction mixture (Table 1).
The copolymerization constants of macromonomer 1´
with compound 2 were calculated by the Kelen—Tudos14
and Feynman—Ross15 methods. The r1´ and r2 values
were 0.057 0.009 and 1.57 0.12 (Kelen—Tudos method)
and 0.055 0.011 and 1.58 0.14 (Feynman—Ross
method). Thus, the r1´ and r2 values obtained by the
Kelen—Tudos and Feynman—Ross methods are in acꢀ
cordance.
Thus, free radicals are formed in the reaction mixture
and react with the double bonds of polymer 1´ and monoꢀ
mer 2 to form radicals 1´• and 2•, respectively. The iniꢀ
tiation process can be presented as Scheme 2.
At high concentration of 1´ (and, hence, at low conꢀ
centration of 2) step (3) determines the formation of acꢀ
tive centers to a less extent. With an increase in the molar
Table 1. Dependence of the copolymer composition on the molar ratio of 1´ and 2 in the reaction solution
М1´
М2
Yield of Composition of copolymers (%) [η]
Elemental composition (%)
copolyꢀ
(%)
/dL g–1
m1´
m2
С
Н
Cl
N
mers
5
95
90
85
80
60
40
20
10
86
3.1
6.3
9.0
11.9
24.3
36.7
46.4
51.7
96.9
93.7
91.0
88.1
75.7
63.3
53.6
48.3
1.7
1.5
1.2
1.0
0.8
0.7
0.6
0.5
51.30
51.86
52.31
52.76
54.39
55.67
56.50
56.90
7.24
7.42
7.57
7.72
8.25
8.67
8.97
9.07
1.49
2.92
4.04
5.17
9.28
12.50
14.60
15.60
0.59
1.15
1.59
2.04
3.66
4.93
5.77
6.14
10
15
20
40
60
80
90
78
71
69
65
53
49
47

538
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 3, March, 2007
Kalyazina et al.
Scheme 2
results in the decrease in the extent of its incorporation
into the copolymer composition. As a result, the coꢀ
polymers with a high content of the cationic groups are
formed.
Thus, the radical copolymerization of macromonoꢀ
mer 1´ with compound 2 makes it possible to prepare
highꢀmolecularꢀweight copolymers in good yield and with
a high content of the cationic groups (up to ~50%), which
was impossible for the copolymerization of monomeric 1
with compound 2. The specific features of the copolyꢀ
merization are caused by the nature of the comonomers
and also by the viscosity of the reaction medium, which is
higher for the copolymerization of the macromonomer
and the second comonomer than that for the copolymerꢀ
ization of two comonomers. Varying the initial ratio of 1´
and 2 and controlling the viscosity of the reaction soluꢀ
tion, one can synthesize copolymers with different conꢀ
tents of the cationic groups. The cyclolinear structure of
the cationic blocks provides the high charge density due
to which the synthesized copolymers become additionally
valuable and the boundaries of their possible use are exꢀ
tended.
It has previously been shown10,11,17 that during the
homopolymerization of monomer 1 the chain transfer
to the monomer results in the formation of radicals caꢀ
pable of continuing the kinetic chain upon the cleavage
of the material chain, i.e., the efficient chain transfer
to the monomer occurs to form the terminal double
bonds. The copolymerization of macromonomer 1´
with compound 2 was carried out at these double bonds,
and the corresponding copolymers of different compoꢀ
sition were synthesized and identified for the first time.
It is found that the radical copolymerization with the
vinylic monomers can be performed at the terminal
double bonds in macromolecules 1´, resulting in the forꢀ
mation of highꢀcation copolymers. The copolymerization
constants of macromonomer 1´ with compound 2 were
determined.
1´ + О Н•
2 + ОН•
1´•
2•
(2)
(3)
fraction of 1´ in a monomeric mixture, step (2) becomes
rateꢀdetermining to an increasing extent. At the same
time, an increase in the concentration of macromonoꢀ
mer 1´ (which is inevitable with an increase in its molar
fraction in a monomeric mixture) increases the viscosity
of the initial monomeric mixture, decreasing the probꢀ
ability of collisions of the terminal double bonds of the
macromolecules with the active radicals. As a result, the
efficiency of reaction (2) decreases and, as a consequence,
the yield and viscosity of the product decrease (see
Table 1). This is confirmed by the above mentioned exꢀ
periments, which showed that in the absence of comꢀ
pound 2 macromonomer 1´ does not react in postꢀpolyꢀ
merization, perhaps because of too low concentration of
active centers localized at the ends of the polymeric molꢀ
ecules at high viscosity of the solution and steric hinꢀ
drance caused by large sizes of macromolecules 1´.
Thus, the formation of copolymers with a high conꢀ
tent of cationic groups is due to the fact that one elemenꢀ
tary act of the interaction of 1´ introduces several charged
groups (instead of one group as in the case of copolymerꢀ
ization with monomeric compound 1) to the copolymer
composition rather than by the high reactivity of the
macromonomer. The number of these groups is deterꢀ
mined by the degree of polymerization of 1, which was
characteristic of macromonomer 1´ introduced into coꢀ
polymerization with compound 2. In other words, as alꢀ
ready mentioned above, the formation of copolymers with
a high content of the cationic groups is due to the fact that
the macromonomer itself represents a ready block of the
cationic monomeric unit. In addition, the copolymer
composition is also determined by a decrease in the probꢀ
ability of collisions of the acrylamide molecules and radiꢀ
cals under the conditions of high viscosity of the solution
with an increase in the content of macromonomer 1´ and,
hence, the yield and intrinsic viscosity of the formed coꢀ
polymers decrease in this case (see Table 1). This is caused
by a decrease in the conversion of compound 2, which
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Received August 22, 2006;
in revised form February 8, 2007