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Adiabatic polymerization of acrylamide in aqueous solutions initiated by the system K2S2O8Na2S2O5
Polymer Sdenm U.S.S.R. Vol. 29, No. 2, pp. 388-392, 198"~ Printed in Poland
0032-3950/81 $10.00+ .00 O 1988 Pergamon Journals Ltd.
ADIABATIC POLYMERIZATION OF ACRYLAMIDE IN AQUEOUS SOLUTIONS INITIATED BY THE SYSTEM K2S2Os-Na2S205 * V. F. KURENKOV, T. A. BhmtmDOV and L. L. STUPEN'KOVA S. M. Kirov Institute of Chemical Technology, Kazan V. A. Kargin Research Institute of Polymer Chemistry and Technology, Saratov Branch (Received 8 July 1985)
Kinetics of adiabatic polymerization of acrylamide in aqueous solutions, initiated by the system K2S2OrNa2S2Os, has been studied by measuring the temperature rise in the reaction mixture. The initial rate of the process is given by -d[AA]/dt=kp[AAl t'a7 [K2S2Os]°'53. •[Na2S2Osl°i**, the apparent activation energy being 28.3 kJ/mole. The viscosity-average molecular weight .A~'~increases with increasing monomer concentration and decreasing concentration of the two initiators. OWING to a number of valuable properties, high-molecular-weight polyacrylamide (PAA) finds many applications in various industrial branches [1]. To prepare high-molecular-weight PAA it is necessary to carry out the polymerization in concentrated solutions o f acrylamide (AA), where however the rapidly increasing viscosity and the formation of water-insoluble products due to intermolecular interactions [2] at monomer concentrations higher than 10 to 15 ~o pose serious limitations. These complications may be mostly avoided by carrying out the polymerization in adiabatic regime, where the increasing temperature enhances the flexibility of macromolecules, thus restricting intermolecular interactions and limiting an excess rise of viscosity. As the specific features o f adfabatic acrylamide polymerization have not been investigated in sufficient detail [3-5], we present here the results of a kinetic study of adiabatic polymerization of concentrated aqueous solutions in the presence of the initiating system K2S2Os - N a 2 S 2 O s . Recystallized AA purchased from Mitsubishi Chem. Industries was used throughout: melting point T,,= 84.5°C, content of double bonds 99.0~; less than 0.2 x 10-*Yo copper and iron (atomic absorption spectroscopy). Potassium persulphate (p.a.) was recrystallized from water; sodium metabisulphite was of quality p.a. Dissolved gases (oxygen and carbon dioxide) were removed from redistilled water by prolonged boiling. High purity helium was used. The polymerizations were carried out in a special Dewar flask provided with a stirrer and an inert gas inlet tube. A chromel-coppei thermocouple connected to a KSP-4 potentiometer was used to monitor the temperature (+ 0.2°C). Aqueous solutions of AA, K2S2Os and Na2S205 were purged by helium for 30 rain and then injected into the reaction vessel. Time was measured from the moment of introduction of the Na2S205 solution. The initial temperature was 30°C in all experiments, the * Vysokomol. soyed. A29: No. 2, 348-351, 1987. 388
Adiabatic polymerization of acrylamide
589
Initial volume of the reaction mixture was always 150 cm 3. After 2 hr the reaction mixture w a s diluted with water and the product was precipitated by pouring into isopropyl alcohol, washed with ethanol, and dried to constant weight. Viscosity was measured at 25°C in an Obbelohde-type viscometer (0.54 mm capillary); no kinetic energy correction was necessary as the flow time of solvent (0.5 MNaCI) was 104 sec. The molar mass was calculated from the formula [6] [t/]=7.19 x 10-3 )~r~"77. Kinetics of adiabatic polymerization was evaluated using the following simplifying assumptions [4, 7]: (i) the heat capacities of the monomer and polymer are the same, (ii) no water is lost by evaporation, (iii) all heat evolved results in a temperature rise of the reaction mixture. The time variation of temperature during polymerization is then given by [4, 7]
aT/at =( AHp/C~)( d [MJ/dt) ,
(l)
where zlHp is the reaction enthalpy, Cp is the heat capacity of the system, and [M] is monomer concentration. By solving simultaneously eqn. (1), the equation describing the rate of polymerization, and the Arrhenius equation, we can derive the following expression for the time variation of temperature in polymerization of acrylamide, initiated by the system K2S2Oa - Na2S205:
dT ...... k' [AA] ~ [K2S2Os] ~ [Na2S205] ~'exp ( - Etot/R T) dt P
(2)
where k'p=Ap(2Ai/At) ÷ and Etot=EpWEi/2-Et/2;/lp, Ai, At are the frequency factors of propagation, initiation, and termination, respectively; the quantities E represent the corresponding activation energies. Equation (2) then enables one to determine the parameters characterizing the kinetics of acrylamide polymerization from the measured time dependence of temperature. The initial reaction rate dT/dt was determined from the slope of kinetic curves plotted as (Too- Tt) vs. t (T~o and Tt are the final and running temperature of the reaction mixture, respectively) - cf. Fig. 1. To determine the exponents a (valid for 0.85~<[AA]~<4.93 mole l -J, fl (1.0×10-5~<[K2S2Oa]~< ~<22.5× 10 -5 mole l-Z), and 7 (2x 10-5...<[Na2S20~]-..<44.× 10 - s mole 1. -~) in eqn. (2), dT/dt was plotted in double logarithmic coordinates against the concentration of the monomer and the concentrations of the two initiators (Fig. 2). The results have been condensed into the following empirical lormula for the initial rate of adiabatic polymerization of acrylamide:
- ( d [AA]/dt) = kp [AA] ~'a7 [K2S208]o.53[Na2S205]0.44 Similar values of reaction order with respect to the individual components of the initiating system, and also a reaction order with respect to the monomer higher than in conventional systems, were found also for adiabatic polymerization of AA in dilute solutions, initiated by the system K2820 a- NaHSOa [3]. The values of reaction order with respect to the initiators indicate bimolecular chain termination.
390
V.F. KtmEUKOVet aL
The effect of concentration of individual components present in the reaction mixture on polymer molecular weight , ~ is shown in Fig. 3. The observed changes of M'~ (an increase with the m o n o m e r concentration - curve I - and a decrease with the concentration of K2S2Os - curve 2) are in accord with the general laws governing radical polymerization. The observed lowering of 3~n with the concentration of Na2S205 (curve 3) is connected with increasing concentration of the transfer promoting species H S O ~ . The concentration of Na2S2Os was always smaller than 4.3 x 10 -4 mole I.-1 in our experiments; the reaction S2Os2- + H20~2HSO~ is known to proceed quantitatively at [Na2S205] ~
~ MH+SO:~3
The chain transfer rate constant (0.135) was determined from the functional dependence 4, I l P = f(tHSO~]/tM]),
where P is the number-average degree of polymerization.
5-1o9[NazSz05] 0.6
r0.85
1.2..
1"8
Jl+log EAA] 1.25
'"
16.5
/t'o
#0
P
0
6
12 Time ~min
FIG. 1
0.6 1"2 1"8 5+lo9 [KzSzOs]
Fro. 2
FIe. 1. Time dependence of temperature during polymerization of aerylamido. [Na2S205] x 105 : 1.095 (1), 2.195 (2), 4.368 (3), 21.95 (4), 43.68molel. - t (5). [AA]=2.817, [KaS2Os]=4.444x x 10 -5 mole 1.- 1, To=30oc. FIe. 2. Initial rate of polymerization as a function of concentration of AA (1), K2S2Os (2), and Na2S205 (3); To=30*C. Here and in Fig. 3: 1 - [K2S~Os]=4.444 x 10 -4, [Na2S205]-- 1.105 × 10 -4 molel.-t; 2-[Na2S2Os]f4.384x10 -5, [AA]=2.817molel.-1; 3-[K2S2Os]---4.444x10 -s, [AA] = 2-817 mole 1.- t.
Adiabatic polymerization of acrylamide
391
The apparent overall activation energy for adiabatic acrylamide polymerization was evaluated by plotting the experimental data in Arrhenius coordinates (Fig. 4). For the sake of comparison Fig. 4 includes results obtained by using the system K2S20 8Na2S2Os (curve 1) and K2S20 8 alone (curve 2) as the initiator; Etot was 28.3 kJ/mole in the former (30°C~< T~<49°C) and 71.0 kJ/mole in the latter case (35°C~
f NazSzOsJ"lO4,mole/l I
1
3
I
I
I'0 [AA]'zm-o°le/l" 12~" J
i
I
1-7
1"2
/'5 +
1"3
l
3 [KzSz08] ,lO#~roole/l.
I
1
i
3" I
3"2
3"3
FIG. 3
TM
Io3/~ K-'
FIG. 4
FIG. 3. AT/,plotted against the concentration of AA (1), of K2S2Os (2) and of NazS20~ (3); To = 30"C. Fro. 4. Initial polymerization rate as a function of reciprocal absolute temperature; initiator K2S2OrNa2S~O5 (1) and K2S2Oa alone (2). 1-[AA]=2.817, [K2S2Oa]=4.444x 10 -4 , [Na2S20~]= 1-105 x 10 -4 mole 1.- 1; 2 - [AA] =2.817, [K2S2Oo]= 1.481 x 10 -a mole 1.- 1. The obtained results demonstrate that water-soluble, high-molecular-weight polymers (A~t~= (0.3-12) x l06) can be prepared by adiabatic polymerization of acrylamide in concentrated aqueous solutions (6 to 35 wt. ~); conversion in our experiments was always >90~o. The molecular weight of the product can be controlled by varying the concentration of the monomer or of the components of the initiating system.
Translated by M. KuBtN REFERENCES
1. A. F. NIKOLAYEV and G. I. OKHRIMENKO, Vodorastvorimye polimery (Water-Soluble Polymers). p. 144, Khimiya, Leningrad, 1979 2. A. SHAPIRO, Radiation Chemistry of Polymeric Systems, p. 326, Interscience, N. Y. - L., 1962 3. K. POHL and F. RODRIGUEZ, J. Appl. Polym. Sci. 26: 611, 1980 4. T. A. KAY and F. RODRIGUEZ, J. Appl. Polym. Sci. 28: 633, t983
392
Z.M. RzAYEV et al.
5. R.A.M. THOMPSON, Makromol. Chem. 184: 1885, 1983 6. J. KLEIN and K.-D. CONRAD, Makromol. Chem. 181: 227, 1980 7. A. O. TONOYAN and N. S. YENIKOLOPYAN, Vysokomol. soyed. A15: 1847, 1973 (Translated in Polymer Sci. U.S.S.R. 15: 8, 2080, 1973) 8. F. A. COTTON and G. WILKINSON, Advanced Inorganic Chemistry, 2nd Ed., p. 545, Wiley Eastern Reprint, N. Y., 1972 9. M. CVETKOVSKA, T. GRCEV and G. PETROV, Makromol. Chem. 185: 429, 1984
Polymer Science U.S.S.R. Vol. 29, No. 2, pp. 392-399, 1987. Printed in Poland
0032-3950/87 $10.00+ .00 © 1988 Pergamon Journals Ltd.
RELATIONSHIPS IN THE FORMATION AND PHOTOTRANSFORMATIONS OF ALTERNATING COPOLYMERS OF MALEIC ANHYDRIDE WITH ALLYLACETATES, AND THEIR TIN-CONTAINING DERIVATIVES* Z. M. RZAYEV, S. G. MAMEDOVA, NK. SH. RAS'JLOV and U. Ku. AOavEv Institute of Chloroorganic Synthesis, Az.S.S.R. Academy of Sciences (Received 9 July 1985)
Relationships in the complex-radical copolymerization of maleic anhydride with substituted allylacetates of the general formula X-CH2-COOCH2CH=CH2 (where X= H, CHa or C1) were elucidated. The complex-formation and copolymerization constants were determined, as well as the role of the complexes in the mechanism of the alternating copolymerization. A symbatic dependence between Kc and the quantitative contribution of the complexes to the chain growth reaction was revealed in the series CH3 > H > CI and it was shown that the radical alternating copolymerization proceeds by the mechanism involving allyl resonance suppression by the complexomers. New organotin polymer analogues were prepared by the reaction of the alternating anhydride-containing copolymers with hexa-nbutyldistannoxane, and some special features of their transformations by UV-radiation were revealed. SOME special features of the alternating copolymer formation between allylic monomers and maleic acid derivatives [1, 2] have previously been investigated, as well as the photochemical transformations of tin-containing oligomers and polymers [3, 4]. The aim of the present work was the elucidation of radical alternating copolymerization of allylacetate (AA), allylpropionate (AP) and allylchloroacetate (ACA) with maleic anhydride (MA) and of the photochemical crosslinking of the prepared tin-containing derivatives of the copolymers based on the above mentioned comonomer pairs. * Vysokomol. soyed. 29: No. 2, 352-357, 1987.
0032-3950/81 $10.00+ .00 O 1988 Pergamon Journals Ltd.
ADIABATIC POLYMERIZATION OF ACRYLAMIDE IN AQUEOUS SOLUTIONS INITIATED BY THE SYSTEM K2S2Os-Na2S205 * V. F. KURENKOV, T. A. BhmtmDOV and L. L. STUPEN'KOVA S. M. Kirov Institute of Chemical Technology, Kazan V. A. Kargin Research Institute of Polymer Chemistry and Technology, Saratov Branch (Received 8 July 1985)
Kinetics of adiabatic polymerization of acrylamide in aqueous solutions, initiated by the system K2S2OrNa2S2Os, has been studied by measuring the temperature rise in the reaction mixture. The initial rate of the process is given by -d[AA]/dt=kp[AAl t'a7 [K2S2Os]°'53. •[Na2S2Osl°i**, the apparent activation energy being 28.3 kJ/mole. The viscosity-average molecular weight .A~'~increases with increasing monomer concentration and decreasing concentration of the two initiators. OWING to a number of valuable properties, high-molecular-weight polyacrylamide (PAA) finds many applications in various industrial branches [1]. To prepare high-molecular-weight PAA it is necessary to carry out the polymerization in concentrated solutions o f acrylamide (AA), where however the rapidly increasing viscosity and the formation of water-insoluble products due to intermolecular interactions [2] at monomer concentrations higher than 10 to 15 ~o pose serious limitations. These complications may be mostly avoided by carrying out the polymerization in adiabatic regime, where the increasing temperature enhances the flexibility of macromolecules, thus restricting intermolecular interactions and limiting an excess rise of viscosity. As the specific features o f adfabatic acrylamide polymerization have not been investigated in sufficient detail [3-5], we present here the results of a kinetic study of adiabatic polymerization of concentrated aqueous solutions in the presence of the initiating system K2S2Os - N a 2 S 2 O s . Recystallized AA purchased from Mitsubishi Chem. Industries was used throughout: melting point T,,= 84.5°C, content of double bonds 99.0~; less than 0.2 x 10-*Yo copper and iron (atomic absorption spectroscopy). Potassium persulphate (p.a.) was recrystallized from water; sodium metabisulphite was of quality p.a. Dissolved gases (oxygen and carbon dioxide) were removed from redistilled water by prolonged boiling. High purity helium was used. The polymerizations were carried out in a special Dewar flask provided with a stirrer and an inert gas inlet tube. A chromel-coppei thermocouple connected to a KSP-4 potentiometer was used to monitor the temperature (+ 0.2°C). Aqueous solutions of AA, K2S2Os and Na2S205 were purged by helium for 30 rain and then injected into the reaction vessel. Time was measured from the moment of introduction of the Na2S205 solution. The initial temperature was 30°C in all experiments, the * Vysokomol. soyed. A29: No. 2, 348-351, 1987. 388
Adiabatic polymerization of acrylamide
589
Initial volume of the reaction mixture was always 150 cm 3. After 2 hr the reaction mixture w a s diluted with water and the product was precipitated by pouring into isopropyl alcohol, washed with ethanol, and dried to constant weight. Viscosity was measured at 25°C in an Obbelohde-type viscometer (0.54 mm capillary); no kinetic energy correction was necessary as the flow time of solvent (0.5 MNaCI) was 104 sec. The molar mass was calculated from the formula [6] [t/]=7.19 x 10-3 )~r~"77. Kinetics of adiabatic polymerization was evaluated using the following simplifying assumptions [4, 7]: (i) the heat capacities of the monomer and polymer are the same, (ii) no water is lost by evaporation, (iii) all heat evolved results in a temperature rise of the reaction mixture. The time variation of temperature during polymerization is then given by [4, 7]
aT/at =( AHp/C~)( d [MJ/dt) ,
(l)
where zlHp is the reaction enthalpy, Cp is the heat capacity of the system, and [M] is monomer concentration. By solving simultaneously eqn. (1), the equation describing the rate of polymerization, and the Arrhenius equation, we can derive the following expression for the time variation of temperature in polymerization of acrylamide, initiated by the system K2S2Oa - Na2S205:
dT ...... k' [AA] ~ [K2S2Os] ~ [Na2S205] ~'exp ( - Etot/R T) dt P
(2)
where k'p=Ap(2Ai/At) ÷ and Etot=EpWEi/2-Et/2;/lp, Ai, At are the frequency factors of propagation, initiation, and termination, respectively; the quantities E represent the corresponding activation energies. Equation (2) then enables one to determine the parameters characterizing the kinetics of acrylamide polymerization from the measured time dependence of temperature. The initial reaction rate dT/dt was determined from the slope of kinetic curves plotted as (Too- Tt) vs. t (T~o and Tt are the final and running temperature of the reaction mixture, respectively) - cf. Fig. 1. To determine the exponents a (valid for 0.85~<[AA]~<4.93 mole l -J, fl (1.0×10-5~<[K2S2Oa]~< ~<22.5× 10 -5 mole l-Z), and 7 (2x 10-5...<[Na2S20~]-..<44.× 10 - s mole 1. -~) in eqn. (2), dT/dt was plotted in double logarithmic coordinates against the concentration of the monomer and the concentrations of the two initiators (Fig. 2). The results have been condensed into the following empirical lormula for the initial rate of adiabatic polymerization of acrylamide:
- ( d [AA]/dt) = kp [AA] ~'a7 [K2S208]o.53[Na2S205]0.44 Similar values of reaction order with respect to the individual components of the initiating system, and also a reaction order with respect to the monomer higher than in conventional systems, were found also for adiabatic polymerization of AA in dilute solutions, initiated by the system K2820 a- NaHSOa [3]. The values of reaction order with respect to the initiators indicate bimolecular chain termination.
390
V.F. KtmEUKOVet aL
The effect of concentration of individual components present in the reaction mixture on polymer molecular weight , ~ is shown in Fig. 3. The observed changes of M'~ (an increase with the m o n o m e r concentration - curve I - and a decrease with the concentration of K2S2Os - curve 2) are in accord with the general laws governing radical polymerization. The observed lowering of 3~n with the concentration of Na2S205 (curve 3) is connected with increasing concentration of the transfer promoting species H S O ~ . The concentration of Na2S2Os was always smaller than 4.3 x 10 -4 mole I.-1 in our experiments; the reaction S2Os2- + H20~2HSO~ is known to proceed quantitatively at [Na2S205] ~
~ MH+SO:~3
The chain transfer rate constant (0.135) was determined from the functional dependence 4, I l P = f(tHSO~]/tM]),
where P is the number-average degree of polymerization.
5-1o9[NazSz05] 0.6
r0.85
1.2..
1"8
Jl+log EAA] 1.25
'"
16.5
/t'o
#0
P
0
6
12 Time ~min
FIG. 1
0.6 1"2 1"8 5+lo9 [KzSzOs]
Fro. 2
FIe. 1. Time dependence of temperature during polymerization of aerylamido. [Na2S205] x 105 : 1.095 (1), 2.195 (2), 4.368 (3), 21.95 (4), 43.68molel. - t (5). [AA]=2.817, [KaS2Os]=4.444x x 10 -5 mole 1.- 1, To=30oc. FIe. 2. Initial rate of polymerization as a function of concentration of AA (1), K2S2Os (2), and Na2S205 (3); To=30*C. Here and in Fig. 3: 1 - [K2S~Os]=4.444 x 10 -4, [Na2S205]-- 1.105 × 10 -4 molel.-t; 2-[Na2S2Os]f4.384x10 -5, [AA]=2.817molel.-1; 3-[K2S2Os]---4.444x10 -s, [AA] = 2-817 mole 1.- t.
Adiabatic polymerization of acrylamide
391
The apparent overall activation energy for adiabatic acrylamide polymerization was evaluated by plotting the experimental data in Arrhenius coordinates (Fig. 4). For the sake of comparison Fig. 4 includes results obtained by using the system K2S20 8Na2S2Os (curve 1) and K2S20 8 alone (curve 2) as the initiator; Etot was 28.3 kJ/mole in the former (30°C~< T~<49°C) and 71.0 kJ/mole in the latter case (35°C~
f NazSzOsJ"lO4,mole/l I
1
3
I
I
I'0 [AA]'zm-o°le/l" 12~" J
i
I
1-7
1"2
/'5 +
1"3
l
3 [KzSz08] ,lO#~roole/l.
I
1
i
3" I
3"2
3"3
FIG. 3
TM
Io3/~ K-'
FIG. 4
FIG. 3. AT/,plotted against the concentration of AA (1), of K2S2Os (2) and of NazS20~ (3); To = 30"C. Fro. 4. Initial polymerization rate as a function of reciprocal absolute temperature; initiator K2S2OrNa2S~O5 (1) and K2S2Oa alone (2). 1-[AA]=2.817, [K2S2Oa]=4.444x 10 -4 , [Na2S20~]= 1-105 x 10 -4 mole 1.- 1; 2 - [AA] =2.817, [K2S2Oo]= 1.481 x 10 -a mole 1.- 1. The obtained results demonstrate that water-soluble, high-molecular-weight polymers (A~t~= (0.3-12) x l06) can be prepared by adiabatic polymerization of acrylamide in concentrated aqueous solutions (6 to 35 wt. ~); conversion in our experiments was always >90~o. The molecular weight of the product can be controlled by varying the concentration of the monomer or of the components of the initiating system.
Translated by M. KuBtN REFERENCES
1. A. F. NIKOLAYEV and G. I. OKHRIMENKO, Vodorastvorimye polimery (Water-Soluble Polymers). p. 144, Khimiya, Leningrad, 1979 2. A. SHAPIRO, Radiation Chemistry of Polymeric Systems, p. 326, Interscience, N. Y. - L., 1962 3. K. POHL and F. RODRIGUEZ, J. Appl. Polym. Sci. 26: 611, 1980 4. T. A. KAY and F. RODRIGUEZ, J. Appl. Polym. Sci. 28: 633, t983
392
Z.M. RzAYEV et al.
5. R.A.M. THOMPSON, Makromol. Chem. 184: 1885, 1983 6. J. KLEIN and K.-D. CONRAD, Makromol. Chem. 181: 227, 1980 7. A. O. TONOYAN and N. S. YENIKOLOPYAN, Vysokomol. soyed. A15: 1847, 1973 (Translated in Polymer Sci. U.S.S.R. 15: 8, 2080, 1973) 8. F. A. COTTON and G. WILKINSON, Advanced Inorganic Chemistry, 2nd Ed., p. 545, Wiley Eastern Reprint, N. Y., 1972 9. M. CVETKOVSKA, T. GRCEV and G. PETROV, Makromol. Chem. 185: 429, 1984
Polymer Science U.S.S.R. Vol. 29, No. 2, pp. 392-399, 1987. Printed in Poland
0032-3950/87 $10.00+ .00 © 1988 Pergamon Journals Ltd.
RELATIONSHIPS IN THE FORMATION AND PHOTOTRANSFORMATIONS OF ALTERNATING COPOLYMERS OF MALEIC ANHYDRIDE WITH ALLYLACETATES, AND THEIR TIN-CONTAINING DERIVATIVES* Z. M. RZAYEV, S. G. MAMEDOVA, NK. SH. RAS'JLOV and U. Ku. AOavEv Institute of Chloroorganic Synthesis, Az.S.S.R. Academy of Sciences (Received 9 July 1985)
Relationships in the complex-radical copolymerization of maleic anhydride with substituted allylacetates of the general formula X-CH2-COOCH2CH=CH2 (where X= H, CHa or C1) were elucidated. The complex-formation and copolymerization constants were determined, as well as the role of the complexes in the mechanism of the alternating copolymerization. A symbatic dependence between Kc and the quantitative contribution of the complexes to the chain growth reaction was revealed in the series CH3 > H > CI and it was shown that the radical alternating copolymerization proceeds by the mechanism involving allyl resonance suppression by the complexomers. New organotin polymer analogues were prepared by the reaction of the alternating anhydride-containing copolymers with hexa-nbutyldistannoxane, and some special features of their transformations by UV-radiation were revealed. SOME special features of the alternating copolymer formation between allylic monomers and maleic acid derivatives [1, 2] have previously been investigated, as well as the photochemical transformations of tin-containing oligomers and polymers [3, 4]. The aim of the present work was the elucidation of radical alternating copolymerization of allylacetate (AA), allylpropionate (AP) and allylchloroacetate (ACA) with maleic anhydride (MA) and of the photochemical crosslinking of the prepared tin-containing derivatives of the copolymers based on the above mentioned comonomer pairs. * Vysokomol. soyed. 29: No. 2, 352-357, 1987.