Radiation synthesis of low swelling acrylamide based hydrogels and ...
Radiation synthesis of low swelling acrylamide based hydrogels and ...
Radiation synthesis of low swelling acrylamide based hydrogels and ...
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378 N. Mahmudi et al. / Nucl. Instr. <strong>and</strong> Meth. in Phys. Res. B 265 (2007) 375–378<br />
Stress, kPa<br />
150<br />
125<br />
100<br />
75<br />
50<br />
25<br />
1: 0.2AAm0.2MAAm2MBA<br />
2: 0.2AAm0.2MAAm4MBA<br />
3: 0.2AAm0.2MAAm6MBA<br />
3<br />
2<br />
1<br />
<strong>and</strong> Table 2 for the sample <strong>of</strong> (0.2AAm/0.2MAAm/<br />
2MBA) composition, only a difference <strong>of</strong> 0.02 in v parameter<br />
caused 4.8-fold increase in the M c value. For the<br />
second (0.2AAm/0.2MAAm/4MBA) <strong>and</strong> third (0.2AAm/<br />
0.2MAAm/6MBA) samples a change in v parameter by<br />
0.01 caused 2.3 <strong>and</strong> 1.2 fold increase in M c , respectively.<br />
Also, for the (1AAm/1HEMA/0.05MBA), (1AAm/<br />
1HEMA/0.1MBA), (1AAm/1HEMA/0.2MBA), 0.01 difference<br />
in v parameter caused for 0.85; 0.75; 0.66 fold<br />
increase in M c :<br />
Fig. 3. k<br />
M c<br />
x 10 3<br />
40<br />
30<br />
20<br />
10<br />
0<br />
0.00 0.25 0.50 0.75 1.00 1.25<br />
-(λ-λ -2 )<br />
k 2 versus stress curves <strong>of</strong> AAm/MAAm/MBA <strong>hydrogels</strong>.<br />
1: 0.2AAm0.2MAAm2MBA<br />
2: 0.2AAm0.2MAAm4MBA<br />
3: 0.2AAm0.2MAAm6MBA<br />
1<br />
2<br />
3<br />
4. Conclusions<br />
The aim <strong>of</strong> this study was to determine molecular weight<br />
between cross-links <strong>and</strong> effective cross-link density <strong>of</strong> radiation<br />
synthesized AAm/MAAm/MBA <strong>and</strong> AAm/HEMA/<br />
MBA <strong>hydrogels</strong> by using data from <strong>swelling</strong> analyses <strong>and</strong><br />
compression tests. Values calculated from mechanical tests<br />
were found to be quite different from those obtained by<br />
using <strong>swelling</strong> experiments. Large difference was attributed<br />
to the incorrect value <strong>of</strong> the v parameter used in the modified<br />
Flory–Rehner equation. These results clearly show<br />
that for reliable determination <strong>of</strong> cross-link density <strong>of</strong><br />
<strong>hydrogels</strong> by <strong>swelling</strong> experiments the v parameter must<br />
be known reliably or determined experimentally.<br />
References<br />
0<br />
0.50 0.51 0.52 0.53 0.54 0.55 0.56 0.57<br />
χ<br />
Fig. 4. The change <strong>of</strong> M c with v value <strong>of</strong> AAm/MAAm/MBA <strong>hydrogels</strong>.<br />
obtained, Fig. 4 by using v <strong>and</strong> experimentally obtained<br />
polymer <strong>based</strong> parameter. As can be seen from Fig. 4<br />
[1] J.E. Mark, B. Erman (Eds.), Rubberlike Elasticity a Molecular Primer,<br />
Wiley, NewYork, 1988.<br />
[2] M. Sßen, N. Pekel, O. Güven, Angew. Macromol. Chem. 251 (1998) 1.<br />
[3] O. Okay, S. Durmaz, Polymer 43 (2002) 1215.<br />
[4] O. Uzun, M. Hassnisaber, M. Sßen, O. Güven, Nucl. Instr. <strong>and</strong> Meth. B<br />
208 (2003) 242.<br />
[5] W. Xue, S. Champ, M.B. Huglin, Polymer 42 (2001) 3665.
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