2.1.8.2. Absorbency Under Load (AUL) - BADA

In the present work, increasing the concentration of GLA caused to change the color of the bulk
from beige to dark brown. The swelling capacity of the IZP-hydrogel was decreased with
increasing the concentration of GLA, because the excess of crosslinker may be reduced the
hydrophilic functional groups of superabsorbent hydrogel. In general, the higher amount of
crosslinker can lead to less flexibility and poor elasticity, so the hydrogel can not extend and keep
a large quantity of water.
Sw elling (g/g)
100
75
50
25
0
0 0.02 0.04 0.06 0.08 0.1
Glutaraldehyde Concentration (mol/L)
Figure 33. Effect of GLA concentration on the swelling capacity of EDTAD-IZP hydrogel
3.5.Ⅱ. Effect of Buffer Solution
The change of the equilibrium swelling degree of IZP hydrogel as a meaning of the pH of the
buffered solution is shown in Figure 34. In the range of pH 3–5.0 the equilibrium swelling capacity
was particularly low and showed a little change with pH, but at pH 5.0 was started to rise of the
equilibrium swelling degree. In case of IZP superabsorbent hydrogel a jump was observed from
pH 7 to pH 8. The water uptake capacity increased from 31.5 g water / g dry gel at pH 3 to about
68 g water / g dry gel at pH 8.
Figure 34 clearly illustrates, swelling of the modified IZP- hydrogel increased significantly when
the pH increased in the alkaline buffer solution (pH 8) at 25±2° C.
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