ISSN 0012-5008, Doklady Chemistry, 2008, Vol. 418, Part 1, pp. 8–9. © Pleiades Publishing, Ltd., 2008.Original Russian Text © P.A. Podkuiko, L.Ya. Tsarik, K.A. Abzaeva, M.G. Voronkov, 2008, published in Doklady Akademii Nauk, 2008, Vol. 418, No. 1, pp. 59–61.

8

Water-soluble metal salts of polyacrylic acid attractattention not only due to the peculiarity of their macro-molecular structure [1–3] but also due to numerouspotential practical applications [4–11].

In this paper, we report the synthesis of previouslyunknown mixed water-soluble bimetallic salts of poly-acrylic (PAA) and polymethacrylic (PMAA) acidssimultaneously containing sodium and another metal(Ca, Mg, Zn, Al, Sn, Mn, Fe, Co, Ni) and the results ofstudy of their composition, structure, and physico-chemical properties.

Unlike the reported synthetic routes to metal salts ofacrylic and methacrylic acid monomers and polymers[1], the bimetallic PAA and PMAA salts were preparedby radical polymerization of these acids in an aqueoussolution initiated by potassium persulfate in the pres-ence of the chloride of the required metal at room tem-perature.

To this end, acrylic acid (1.8–2.2 mol) or meth-acrylic acid (1.5–1.8 mol) was added to an aqueous

solution of the initiator (K

2

S

2

O

8

, 0.014 mol) and thereaction mixture was stirred for 30 min. Then, an aque-ous solution of the corresponding metal chloride(1.6

−

6.3 g/L) was added. The reaction was carried outfor 3 h with continuous stirring at room temperature.The reaction mixture was diluted threefold with water.The unreacted acid was titrated by an aqueous solutionof NaOH (3.9 mol/L) to pH 8–9 while preventing thereaction mixture from warming up. The aqueous solu-tion of the PAA or PMAA double salt was passedthrough columns with commercial ion-exchange resinsin the appropriate form. Water was removed from thethus-purified solution, and the resulting polymeric saltswere isolated as films, which were dried in vacuum at90

°

C to a constant weight.

The elemental analysis data of bimetallic polyacry-lates prepared in this way are summarized in the table.

The elemental analysis data (table) were used to cal-culate the compositions of the PAA or PMAA doublemetallic salts corresponding to the general formula

[(–ëH

2

ëRëéé)

x

M

x

–)]

n

(–ëH

2

ëRëééNa–)

m

(–ëH

2

ëRëééH–)

k

,

where R = H (acrylates) or CH

3

(methacrylates) and

x

is the oxidation state of the metal.The composition and structure of the resulting

mixed bimetallic polyacrylates and polymethacrylateswere also confirmed by IR spectroscopy and

1

H and

13

CNMR spectroscopy.

The IR spectra of bimetallic polyacrylates exhibitthe following vibration frequencies (KBr,

ν

, cm

–1

):1470, 2920, 3000 (ëH

2

), 1320

, 2840 (sh) (CH), 1420,3050, 3550 (OH), 1550 (C=O), 1400, 1450, 1550,1600,

1750 (ëéé

–

)

.The IR spectra of bimetallic polymethacrylates

exhibit the following frequencies (KBr,

ν

, cm

–1

): 1380

,1460, 1470, 1490 (CH

3

), 1470, 2850, 3000 (CH

2

),

1340, 2890 (CH), 1420, 2500, 3000, 3550 (OH), 1500(C=O), 1400, 1550, 1610 (COO

–

).The positions of the doublet or triplet absorption

bands of the

ëéé

–

group depend on the oxidation stateand the coordination number of the metal M. The broadband at 3050–3550 cm

–1

and a doublet or a triplet at1700 or 1720 cm

–1

characterize the association of unco-ordinated carboxyl groups. The absorption region ofthe carboxylate anions (1400, 1550, and 1610 cm

–1

) inthe bimetallic polyacrylates and polymethacrylatesindicates that these groups are bidentate ligands. Thedependence of the position and intensity of the C=Oabsorption band on the nature of the metal indicates thatthis group is involved in complexation.

The

1

H NMR spectra of bimetallic polyacrylatesexhibit singlets (

δ

, ppm,

D

2

O) at 2.29

(CH), 3.5 (OCH),4.3 (COOH), and 4.73 (OH) and a doublet at 1.58(CH

2

).

Water-Soluble Bimetallic Saltsof Polyacrylic and Polymethacrylic Acids

P. A. Podkuiko, L. Ya. Tsarik, K. A. Abzaeva, and

Academician

M. G. Voronkov

Received July 19, 2007

DOI:

10.1134/S0012500808010035

Irkutsk State University, ul. Lermontova 126, Irkutsk, 664033 Russia

CHEMISTRY

DOKLADY CHEMISTRY

Vol. 418

Part 1

2008

WATER-SOLUBLE BIMETALLIC SALTS 9

The

13

C NMR spectrum of bimetallic polyacrylatescontains the following signals (

δ

, ppm):

36.73 (ëH

2

),43.34

(CH), 64.14 (OCH), 180.23 (C=O).The

1

H NMR spectra of bimetallic polymethacry-lates contain the following signals (

δ

, ppm,

D

2

O

): 1.87(t, CH

3

), 1.58 (d, CH

2

), 2.29 (s, CH), 3.55 (OCH), 4.3(COOH), 4.73 (OH).

13

C NMR (

δ

, ppm): 25.30 (CH

3

), 36.73 (CH

2

), 43.34(CH), 64.14 (OCH), 180.23 (C=O).

We studied the hydrodynamic properties of theaqueous solutions of the bimetallic polyacrylates andpolymethacrylates. It was found that they are polyelec-trolytes, as they prone to polyelectrolyte swelling. Theintrinsic viscosities of these polymers were determined;for example, for Fe(III)PAANa, 0.004 dL/g; forCaPAANa, 0.002 dL/g. These values may imply that,for M = Fe(III), the polymer chains are cross-linked byFe

3+

cations, while, in the case where M = Ca

2+

, thiscation is bound to the carboxyl groups of one chain.

The thermal stability of the bimetallic PAA andPMAA salts was studied by thermogravimetry in the20–500

°

C range (heating rate 5 K/min). A 5% loss ofthe sample weight was taken as the initial destructionpoint. The samples completely decomposed at 390–490

°

C. The polymers with M = Al, Sn, Mn, and Fe werethe most stable (decomposed at 490

°

C).Aqueous solutions of the synthesized metal poly-

mers are used as efficient quenching media [6–10] (seealso [11]).

REFERENCES

1. Pomogailo, A.D. and Sevast’yanov, V.S.,

Metallo-soderzhashchie monomery i polimery na ikh osnove

(Metal-Containing Monomers and Polymers on TheirBase), Moscow: Khimiya, 1988.

2. Pomogailo, A.D. and Uflyand, I.E.,

Makromoleku-lyarnye metallokhelaty

(Macromolecular Metalloche-lates), Moscow: Khimiya, 1991.

3. Pomogailo, A.D., Uflyand, I.E., and Vainshtein, E.F.,

Usp. Khim.

, 1995, vol. 64, no. 9, pp. 913–914.4. Abzaeva, K.A., Voronkov, M.G., and Lopyrev, V.A.,

Vysokomol. Soedin., Ser. B

, 1997, vol. 39, no. 11,pp.

1883–1904.5. Zhdanovich, E.L., Azarova, I.N., Erofeeva, L.G., Abza-

eva, K.L., Sherstyannikova, L.V., Annenkova, V.Z., andVoronkov, M.G.,

Zh. Prikl. Khim.

(St. Petersburg), 1997,vol. 70 no. 3, pp. 505–507.

6. Voronkov, M.G. and Abzaeva, K.A.,

Nauka–Proizvod.

,2003, no. 6, pp. 40–41.

7. Podkuiko, P.A., Tsarik, L.Ya., and Zaitsev, N.V.,

Khim.Prom-st.

, 2003, vol. 80, no. 1, pp. 30–34.8. Podkuiko, P.A., Tsarik, L.Ya., and Zaitsev, N.V.,

Khim.Prom-st.

, 2003, vol. 80, no. 3, pp. 10–13.9. Podkuiko, P.A., Tsarik, L.Ya., and Zaitsev, N.V.,

Izv.Vyssh. Uchebn. Zaved., Khim. Khim. Tekhnol.,

2004,vol.

47, no. 8, pp. 32–33.10. Podkuiko, P.A., Tsarik, L.Ya., and Zaitsev, N.V.,

Khim.Prom-st.

, 2004, vol. 81, no. 10, pp. 489–503.11. Voronkov, M.G., Stankevich, V.K., Dianova, N.G.,

Burkov, A.G., Khashchenko, O.V., and Kukharev, B.F.,

Nauka–Proizvod.

, 2003, no. 6, pp. 14–15.

Elemental analysis of polymers

NameFound, %

C H O Na M

AlAlPAANa 38.86 3.70 35.51 21.54 0.39

41.48 3.94 37.04 17.44 0.09AlPMAANa 36.17 3.89 42.67 19.04 0.04

34.37 3.30 42.57 19.56 0.19Fe

2+

FePAANa 39.31 3.67 34.60 21.55 0.8641.59 3.94 36.86 17.44 0.18

FePMAANa 34.92 3.25 42.67 19.04 0.1334.98 3.39 42.48 17.14 0.02

Fe

3+

FePAANa 38.75 3.66 35.4 21.55 0.6441.33 3.92 37.16 17.44 0.14

FePMAANa 35.40 3.41 41.26 19.56 0.3636.04 3.34 41.75 18.78 0.07

CaCaPAANa 39.18 3.62 35.42 21.55 0.62

41.47 3.93 37.04 17.44 0.13CaPMAANa 34.26 3.28 42.56 19.56 0.35

35.79 3.31 42.03 18.78 0.08CoCoPAANa 38.63 3.60 35.31 21.55 0.9

41.44 3.93 37.01 17.44 0.19CoPMAANa 35.54 3.24 42.10 19.04 0.09

34.19 3.26 42.53 19.56 0.47MgMgPAANa 38.82 3.61 35.41 21.55 0.6

41.48 3.93 37.05 17.44 0.11MgPMAANa 34.33 3.30 42.55 19.56 0.25

35.81 3.31 42.04 18.78 0.05MnMnPAANa 39.70 3.57 35.50 21.11 0.13

39.07 3.71 35.65 21.55 0.01MnPMAANa 34.22 3.29 42.48 19.56 0.44

35.81 3.32 42.03 18.78 0.05NiNiPAANa 38.64 3.60 35.30 21.55 0.90

41.45 3.93 37.10 17.44 0.18NiPMAANa 34.21 3.29 42.46 19.56 0.47

35.96 3.33 41.84 18.78 0.08SnSnPAANa 38.50 3.60 35.16 21.55 1.18

41.43 3.92 37.00 17.44 0.22SnPMAANa 34.88 3.38 41.51 19.56 0.66

35.26 3.23 42.65 18.78 0.16ZnZnPAANa 35.53 3.21 40.23 21.11 0.03

38.58 3.60 35.29 21.55 1.00ZnPMAANa 34.19 3.27 42.53 19.56 0.47

35.79 3.31 42.02 18.78 0.09