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ABSTRACT:The gelation of aqueous solutions containing syndiotacticity rich poly(vinyl alcohol) (s-PVA) and Congo red was studied. The gelation occurred even at 40°C, different from aqueous solutions containing atactic PVA (a-PVA) and Congo red. The melting point of gels, which were prepared from the solutions of s-PVA concentration of 2.5% and Congo red concentration of 0.1%, was around 90°C. The size of the junction points in s-PVA/Congo red hydrogels is larger than that of a-PVA/Congo red hydrogels at each fixed Congo red concentration. Syndiotactic sequence length plays an important role in gelation. The melting points and shear moduli of the gels prepared from dilute polymer solution at 0 -40°C changed through a maximum at around 0.1-0.3% of Congo red concentration and also a maximum at around 1.5%, identical to results reported already for a-PVA/Congo red hydrogel prepared at 20°C.

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