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INVESTIGATION OF IN POLYMER ACID GEL – LINEAR POLYBASES SYSTEMS

Earlier [1, 2] “distance effect” in polyacid gel – polybase gel was found and studied. Polyacid gel disposed in water in presence of polybase gel on some distance (1-20 sm) undergoes remarkable additional swelling. For example, swelling coefficient Ksw of polyacrylic acid gel in presence of polyethylene imine gel increases from 22 to 40. This phenomenon was also observed for polyacrylic and polymethacrylic acid gels in presence of polyethylene amine, polyvinylpirrolidone and polyacrylamide gels.

It may be explained by ionization of carboxylic groups of polyacid gel due to influence of nitrogen atoms of polybases, as it was observed in related linear systems polyacrylic acid – polyvinylpyridine with formation of interpolyelectrolyte complexes [3].

In this short communication the possibility of such effect in systems polyacid gel – linear polybases was demonstrated.


The measurements of swelling coefficient were made in cell presented in Figure 1.

Hydrogels of PAA and PMAA were used. As linear polymers polyethylene imine (PEI), polydimethylacrylamide (PDMAA), polyethylene glycole (PEG), polyvinylpirrolidone (PVPd), polyisopropylacrylamide (PIPAA), polydimethylaminoethylmethacrylate (PDMAEMA), polydimethyldiallylammonium chloride (PDMDAACl), poly-4-vinylpirydine (P4VPy) and copolymer acrylamide – acrylic acid (AAm-AA, 95:5) were used.

Swelling coefficient Ksw was measured by gravimetric method:

where m0 – weight of dry gel; m – weight of swelled gel.

Fig. 1. Cell for measurement of swelling coefficient.

1 – linear polymer in water; 2 – semipermeable membrane (permeable only for low molecular ions); 3 – water; 4 – hydrogel.

Initial K0sw of pure gel was measured in 2 weeks. Then the solution of linear polymer was added to cell and Ksw was measured in 2 weeks.

Result of measurements of swelling coefficients presented in Tables 1 and 2.

As can be seen from Tables 1 and 2 the strong increase of swelling coefficient of both polyacid gels is observed. This is also may be explained by ionization of gel carboxylic groups in presence of linear polybases.

It is interesting to check that in case of system g-PMAA-PDMDAACl where the nitrogen atom is charged no change in value of Ksw is observed.

We suppose that “distance effect” may be also observed for viscosity of solution in linear polymer – polymer gel and linear polymer – linear polymer systems.

 

Table 1. Change of swelling coefficient of polyacrylic acid gel in presence of linear polybases

Hydrogel

K0sw

Ksw

Linear polybase

Molecular weight

1

g – PAA

23

142

AA – AK

6 000 000

2

g – PAA

23

113

PDMAA

430 000

3

g – PAA

23

92

PEG

600 000

4

g – PAA

20

88

PDMAEMA

510 000

5

g – PAA

23

63

PIPAA

260 000

6

g – PAA

30

76

PVPD

360 000

7

g – PAA

69

127

PVPD

360 000

8

g – PAA

69

120

PEI

40 000

Table 2. Change of swelling coefficient of polymethacrylic acid gel in presence of linear polybases

Hydrogel

K0sw

Ksw

Linear

polybase

Molecular weight

1

g – PMAA

150

382

PEG

600 000

2

g – PMAA

150

339

PVPd

360 000

3

g - PMAA

150

319

PIPAA

260 000

4

g - PMAA

150

261

P4VPy

60 000

5

g - PMAA

150

323

AAmAA

6000 000

6

g - PMAA

150

127

PDMDAACl

240 000

References

1. Ismailova Sh.A., Dzhumadilov T.K., Bekturov E.A., Izv. Nats. Akad. Nauk Resp. Kazakhstan, Seriya Khim. 2004. No 4. P. 80.

2. Ismailova Sh.A., Dzhumadilov T.K., Bekturov E.A., Vestn. Kaz. Nat. Tech. Univ. 2004. No 3. P. 186.

3. Lutsenko V.V., Zezin A.B., Rudman A.R., Vysokomolec. Soed. 1971. Vol. B13. P. 396.