Suppression of inhomogeneities in hydrogels formed by free-radical crosslinking copolymerization

Nermin Orakdogen, Mine Yener Kizilay, Oguz Okay*

*Bu çalışma için yazışmadan sorumlu yazar

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32 Atıf (Scopus)

Özet

Network microstructures of poly(acrylamide) (PAAm) and poly(N,N- dimethylacrylamide) (PDMA) hydrogels were compared by static light scattering and elasticity measurements. The hydrogels were prepared by free-radical crosslinking copolymerization of the monomers acrylamide (AAm) or N,N-dimethylacrylamide (DMA) with N,N′-methylenebis(acrylamide) as a crosslinker. During the formation of PAAm gels, the reaction time dependence of the scattered light intensity exhibits a maximum at a critical reaction time, while in case of PDMA gels, both a maximum and a minimum were observed, corresponding to the chain overlap threshold and the gel point, respectively. This difference in the time-course between the two gelling systems is due to the late onset of gelation in the DMA system with respect to the critical overlap concentration. Compared to the AAm system, no significant scattered light intensity rise was observed during the crosslinking polymerization of DMA. It was shown that, regardless of the crosslinker ratio and of the initial monomer concentration, PDMA gel is much more homogeneous than the corresponding PAAm gel due to the shift of the gelation threshold to the semidilute regime of the reaction system. The results suggest that the spatial gel inhomogeneity can be controlled by varying the gel point with respect to the critical overlap concentration during the preparation of gels by free-radical mechanism.

Orijinal dilİngilizce
Sayfa (başlangıç-bitiş)11407-11415
Sayfa sayısı9
DergiPolymer
Hacim46
Basın numarası25
DOI'lar
Yayın durumuYayınlandı - 28 Kas 2005

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