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Determining the composition of a copolymer of acrylamide with acrylic acid and its salts
0032-8050/70/0401-1044507.50]0.
Polymer Science U.S.S.R. Voi. 21, pp. 1044-1046. ~ ) Pergamon Press Ltd. 1980. Printed in Poland
~)ETERMINING THE COMPOSITION OF A COPOLYMER OF ACRYLAMIDE WITH ACRYLIC ACID AND ITS SALTS* N . S. SHAGLAYEVA, E . I . BRODSKAYA, A . V. I=~ZHEPKA, V. A . LOPYREV a n d
M. G. VORONKOV I r k u t s k I n s t i t u t e of Organic Chemistry, U.S.S.R. Academy of Sciences
(Received 21 March 1978) A_u I R spectroscopic m e t h o d was developed for determining the composition of a copolymer of acrylamide with acrylic acid and its salts. COPOLYMERS of acrylamide with ~,fl-unsaturated acids or their salts are widely used L~ various branches of the national economy [1]. The efficiency of using these copolymers a s flocculants, as well as some other factors are determined b y the ratio of amide, carboxy]: a n d earboxylatc groups in the macromolecule. I t is obvious t h a t the composition of the e o p o l y m e r is an i m p o r t a n t technical p a r a m e t e r and has to be considered when using a e r y l a m i d o polymers. Methods based on the quantitative determination of nitrogen according tO Kjeldah]~ [2, 3] are most popular for establishing copolymer composition; these methods, however~ a r e inapplicable to copolymers containing a m m o n i u m acrylate and to technical samples. c o n t a m i n a t e d b y impurities containing nitrogen. COMPOSITION
OF ACRYLA-MIDE
COPOLYMERS
Content of units in the copolymer, wt. o/o Sample, :No.
IR-spectroscopy acrylaraide
acrylic acid
acrylate
e l e m e n t a r y analysis acrylic acid acrylamide a n d acrylate
# 1 2 3 4 5
74"4 61-8 81.8 67-2 76.3
13.8 29.7 11.7 15.8 18-4
11"8 8"5 6"5 17"0 5"3
74.1 60-2 82-1 68.3 75.8
25.9 39.8 17.9 31.7 24.2
A potentiometric m e t h o d is known for determining the composition of eopolymers based o n v~rylamide [4, 5]. A shortcoming of this method is the fact t h a t with the joint presence of"
carboxyl, carboxylate groups of ~,fl-unsaturated acids the contents of these groups cannot~ be determined in the copolymer. The existence of a difference in I R spectra of polyacrylamide samples according to the~ degree of hydrolysis was indicated [6, 7]. As it is difficult to determine directly the existence of a non-ionized carboxyl group i ~ eopolymers of acrylamide with acrylic acid (band a t 1704 cm -1 vcooH is overlapped b y * Vysokomol. soyed. 2~1: No. 4, 950-952, 1979. 10~4
Composition of copolymer of acrylamide with acrylic acid and its salts
1045
band at 1680 em -1 VCO~H~), for the q u a n t i t a t i v e detcrmination of earboxyl groups t h e .optical density was measured of a band at 1704 cm -1 of model mixtures obtained by t h e a d d i t i o n of polyacrylic acid to a specially prepared unhydrolysed polyacrylmnide sample free from acid groups. The analytical dependence of optical density D1704 on the content of polyacrylie acid (Fig. 1) is expressed by the equation xl = 50.19yl -- 5-05 s=0.004,
(1)
• R=0.999,
where x~ is wt. °/o of polyacrylic acid, y~--absolute optical density of the absorption band at 1704 cm -~, determined with a conoentration of 3 × 10 -3 g polymer mixture in g KBr; s - - c o r ,relation coefficient and R--dispersion.
Dido 0"8
~';1~to/D~,e
0"4
o
0.2 0.9
5
I0 15 PAA, wt. %
lO
20
Fic. 1
30 *'o A, w~.°/
5g
Fro. 2
FIG. 1. Dependence of optical density D1704 on the content of polyacrylic acid. Fro. 2. Dependence of the optical density ratio D~4~o/D~44s on the content of polyaerylat~ of alkali metal. To determine t h e composition of copolymers of aerylamide with alkali metal acrylates, analytical bands are used at 1410 and 1448 cm -1 corresponding to bond stretching vibrations of COO- and deformation vibrations of the methylene group, respectively. The dependence of the optical density ratio of these absorption bands on the ratio of acrylate and aerylamide units in mixtures of polyacrylamide with alkali metal polyacrylaf~s (Fi g . 2) takes tile form x 2 = 151'33y2-- 125"39 (2) s=0"003 ,
R=0'998 ,
where x~ is the content of acrylate units,
y~--D141o/D144s. The optical density ratio of absorption bands at 1410 and 1448 cm -~ is independent o f the n u m b e r of aerylamide and acrylic acid units. The composition of several eopolymers based on 'acrylamide was calculated by t h e m e t h o d s described and a comparison made with results of elementary analysis. Results are tabulated.
1046
N . A . KUr,A~rovA a n d I. A. LITVI~OV
I R spectra were obtained using a UR-20 spectrophotometer in the region of 400-3600 c m -1. The rate of recording was 64 cm-1/min, slot programme 4 was used and copolymer samples were compressed into pellets with optically pure KBr. The relative error of determin a t i o n was -V2~o. Non-hydrolysed polyacrylamide samples were prepared b y methods previously described [8]. Copolymer samples were prepared directly b y copolymcrization of acrylamide with acrylic acid in a dilute solution in the presence of sodium hydroxide. I n i t i a t i o n was carried out using a n a m m o n i u m persulphate-urea redox system [9].
Translated by E. SEMERE REFERENCES
1. M. N. SAVITSKAYA, Poliakrilamid (Polyacrylamide), Tekhnika, 1969 2. Yu. Yu. LUR'YE a n d A. I. RYBNIKOVA, Khimicheskii analiz proizvodstvennykh i stochnykh r o d (Chemical Analysis of Trade Effluents and Waste Water). Izd. "Khimiya", 1966 3. Tekhnichcskiye ukazaniya po primeneniyu poliakrilamida dlya ochistki p i t ' y e v y k h veal n a gorodskikh vodoprovodaldl, Akademia kommunal'nogo khozyaistva im. I. D. P a m filova (Technical Indications Concerning the Use of Polyacrylamide for the Purification of Drinking W a t e r in the U r b a n Water-supply; I. D. Pamfilov Academy of Municipal Economy). 1966 4. V. P. NEBERA, Izv. Vuzov, Tsvetnaya metallurgiya, No. 3, 12, 1967 5. A. P. BIMBEREKOV a n d B. A. BARYSHNIKOV, Sb. Fiziko-tekhnicheskiye problemy razrabotki poleznykh iskopayemykh (Physical a n d Technical Problems of T r e a t i n g Minerals). Izd. " N a u k a " , 1969 6. M. A. BORTS, O. I. YEGOROVA, V. S. KAMINSKII, V. I. KASATOCHKIN and D. N. STEPANOVA, Koks i khimiya, No. 7, 11, 1968 7. A. P. BIMBEREKOV a n d F. A. BARYSHNIKOV, Sb. Fiziko-tekhnicheskiye problemy razrabotki poleznykh iskopayemykh. Izd. "Nauka", 1975 8. V. F. GROMOV, P. M. KHOMIKOVSKH a n d A. D. ABKIN, Vysokomol. soyed. B12-" 767, 1970 (Not translated in Polymer Sei. U.S.S.R.) 9. N. S. SHABLIYEVA, V. A. LOPYREV, M. G. VORONKOV and A. V. RZHEPKA, Auth~ Cert. 547454, 1976. Bull. izobr., No. 7, 1977
Polymer Science U.S.S.R. Vol. 21, pp. 1046-1049. ~) Pergamon Presa :Ltd. 1980. Printed in Poland
0032-3950/79]0401-1046507.50]@
METHODS OF PREPARING SUPER-FINE SECTIONS OF ACRYLIC FIBRES* N..A.
KULAKOVA a n d I . A. LITVINOV
(Received 2 Auguet 1978) A s t u d y was made of sections of initial and oxidized polyaerylonitril~ fibres obtained at different angles to the fibre axis and perpendicular to tile fibre axis. I t was shown t h a t the deformation of the polyfibrillar fibre stluctule is m i n i m u m when * Vysokomol. soycd. A21: 1~o. 4, 953-955, 1979.
t
Polymer Science U.S.S.R. Voi. 21, pp. 1044-1046. ~ ) Pergamon Press Ltd. 1980. Printed in Poland
~)ETERMINING THE COMPOSITION OF A COPOLYMER OF ACRYLAMIDE WITH ACRYLIC ACID AND ITS SALTS* N . S. SHAGLAYEVA, E . I . BRODSKAYA, A . V. I=~ZHEPKA, V. A . LOPYREV a n d
M. G. VORONKOV I r k u t s k I n s t i t u t e of Organic Chemistry, U.S.S.R. Academy of Sciences
(Received 21 March 1978) A_u I R spectroscopic m e t h o d was developed for determining the composition of a copolymer of acrylamide with acrylic acid and its salts. COPOLYMERS of acrylamide with ~,fl-unsaturated acids or their salts are widely used L~ various branches of the national economy [1]. The efficiency of using these copolymers a s flocculants, as well as some other factors are determined b y the ratio of amide, carboxy]: a n d earboxylatc groups in the macromolecule. I t is obvious t h a t the composition of the e o p o l y m e r is an i m p o r t a n t technical p a r a m e t e r and has to be considered when using a e r y l a m i d o polymers. Methods based on the quantitative determination of nitrogen according tO Kjeldah]~ [2, 3] are most popular for establishing copolymer composition; these methods, however~ a r e inapplicable to copolymers containing a m m o n i u m acrylate and to technical samples. c o n t a m i n a t e d b y impurities containing nitrogen. COMPOSITION
OF ACRYLA-MIDE
COPOLYMERS
Content of units in the copolymer, wt. o/o Sample, :No.
IR-spectroscopy acrylaraide
acrylic acid
acrylate
e l e m e n t a r y analysis acrylic acid acrylamide a n d acrylate
# 1 2 3 4 5
74"4 61-8 81.8 67-2 76.3
13.8 29.7 11.7 15.8 18-4
11"8 8"5 6"5 17"0 5"3
74.1 60-2 82-1 68.3 75.8
25.9 39.8 17.9 31.7 24.2
A potentiometric m e t h o d is known for determining the composition of eopolymers based o n v~rylamide [4, 5]. A shortcoming of this method is the fact t h a t with the joint presence of"
carboxyl, carboxylate groups of ~,fl-unsaturated acids the contents of these groups cannot~ be determined in the copolymer. The existence of a difference in I R spectra of polyacrylamide samples according to the~ degree of hydrolysis was indicated [6, 7]. As it is difficult to determine directly the existence of a non-ionized carboxyl group i ~ eopolymers of acrylamide with acrylic acid (band a t 1704 cm -1 vcooH is overlapped b y * Vysokomol. soyed. 2~1: No. 4, 950-952, 1979. 10~4
Composition of copolymer of acrylamide with acrylic acid and its salts
1045
band at 1680 em -1 VCO~H~), for the q u a n t i t a t i v e detcrmination of earboxyl groups t h e .optical density was measured of a band at 1704 cm -1 of model mixtures obtained by t h e a d d i t i o n of polyacrylic acid to a specially prepared unhydrolysed polyacrylmnide sample free from acid groups. The analytical dependence of optical density D1704 on the content of polyacrylie acid (Fig. 1) is expressed by the equation xl = 50.19yl -- 5-05 s=0.004,
(1)
• R=0.999,
where x~ is wt. °/o of polyacrylic acid, y~--absolute optical density of the absorption band at 1704 cm -~, determined with a conoentration of 3 × 10 -3 g polymer mixture in g KBr; s - - c o r ,relation coefficient and R--dispersion.
Dido 0"8
~';1~to/D~,e
0"4
o
0.2 0.9
5
I0 15 PAA, wt. %
lO
20
Fic. 1
30 *'o A, w~.°/
5g
Fro. 2
FIG. 1. Dependence of optical density D1704 on the content of polyacrylic acid. Fro. 2. Dependence of the optical density ratio D~4~o/D~44s on the content of polyaerylat~ of alkali metal. To determine t h e composition of copolymers of aerylamide with alkali metal acrylates, analytical bands are used at 1410 and 1448 cm -1 corresponding to bond stretching vibrations of COO- and deformation vibrations of the methylene group, respectively. The dependence of the optical density ratio of these absorption bands on the ratio of acrylate and aerylamide units in mixtures of polyacrylamide with alkali metal polyacrylaf~s (Fi g . 2) takes tile form x 2 = 151'33y2-- 125"39 (2) s=0"003 ,
R=0'998 ,
where x~ is the content of acrylate units,
y~--D141o/D144s. The optical density ratio of absorption bands at 1410 and 1448 cm -~ is independent o f the n u m b e r of aerylamide and acrylic acid units. The composition of several eopolymers based on 'acrylamide was calculated by t h e m e t h o d s described and a comparison made with results of elementary analysis. Results are tabulated.
1046
N . A . KUr,A~rovA a n d I. A. LITVI~OV
I R spectra were obtained using a UR-20 spectrophotometer in the region of 400-3600 c m -1. The rate of recording was 64 cm-1/min, slot programme 4 was used and copolymer samples were compressed into pellets with optically pure KBr. The relative error of determin a t i o n was -V2~o. Non-hydrolysed polyacrylamide samples were prepared b y methods previously described [8]. Copolymer samples were prepared directly b y copolymcrization of acrylamide with acrylic acid in a dilute solution in the presence of sodium hydroxide. I n i t i a t i o n was carried out using a n a m m o n i u m persulphate-urea redox system [9].
Translated by E. SEMERE REFERENCES
1. M. N. SAVITSKAYA, Poliakrilamid (Polyacrylamide), Tekhnika, 1969 2. Yu. Yu. LUR'YE a n d A. I. RYBNIKOVA, Khimicheskii analiz proizvodstvennykh i stochnykh r o d (Chemical Analysis of Trade Effluents and Waste Water). Izd. "Khimiya", 1966 3. Tekhnichcskiye ukazaniya po primeneniyu poliakrilamida dlya ochistki p i t ' y e v y k h veal n a gorodskikh vodoprovodaldl, Akademia kommunal'nogo khozyaistva im. I. D. P a m filova (Technical Indications Concerning the Use of Polyacrylamide for the Purification of Drinking W a t e r in the U r b a n Water-supply; I. D. Pamfilov Academy of Municipal Economy). 1966 4. V. P. NEBERA, Izv. Vuzov, Tsvetnaya metallurgiya, No. 3, 12, 1967 5. A. P. BIMBEREKOV a n d B. A. BARYSHNIKOV, Sb. Fiziko-tekhnicheskiye problemy razrabotki poleznykh iskopayemykh (Physical a n d Technical Problems of T r e a t i n g Minerals). Izd. " N a u k a " , 1969 6. M. A. BORTS, O. I. YEGOROVA, V. S. KAMINSKII, V. I. KASATOCHKIN and D. N. STEPANOVA, Koks i khimiya, No. 7, 11, 1968 7. A. P. BIMBEREKOV a n d F. A. BARYSHNIKOV, Sb. Fiziko-tekhnicheskiye problemy razrabotki poleznykh iskopayemykh. Izd. "Nauka", 1975 8. V. F. GROMOV, P. M. KHOMIKOVSKH a n d A. D. ABKIN, Vysokomol. soyed. B12-" 767, 1970 (Not translated in Polymer Sei. U.S.S.R.) 9. N. S. SHABLIYEVA, V. A. LOPYREV, M. G. VORONKOV and A. V. RZHEPKA, Auth~ Cert. 547454, 1976. Bull. izobr., No. 7, 1977
Polymer Science U.S.S.R. Vol. 21, pp. 1046-1049. ~) Pergamon Presa :Ltd. 1980. Printed in Poland
0032-3950/79]0401-1046507.50]@
METHODS OF PREPARING SUPER-FINE SECTIONS OF ACRYLIC FIBRES* N..A.
KULAKOVA a n d I . A. LITVINOV
(Received 2 Auguet 1978) A s t u d y was made of sections of initial and oxidized polyaerylonitril~ fibres obtained at different angles to the fibre axis and perpendicular to tile fibre axis. I t was shown t h a t the deformation of the polyfibrillar fibre stluctule is m i n i m u m when * Vysokomol. soycd. A21: 1~o. 4, 953-955, 1979.
t