Swelling kinetics of poly(<i>N</i>‐vinylimidazole‐<i>co</i>‐sodium styrenesulfonate) hydrogels

Valencia, Joaquín; Piérola, Inés F.

doi:10.1002/app.10059

Cited by 39 publications

(34 citation statements)

References 40 publications

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“…[44] and denoted by w H , because they have a more general applicability than the experimental values and it allows to establish comparisons with other systems. [24,25] P mix is a positive contribution to swelling, small for PVI40(2) and a bit larger for PVI40(15) ( Table 2 and 3). The elastic contribution of the hydrogel deformed with respect to the reference or relaxed state (the network after synthesis and before swelling) is [27,28] …”

Section: Discussionmentioning

confidence: 99%

“…They regulate the pH of the bath in which they are immersed, [20,21] in ethanol they swell or collapse depending on the microstructure controlled by the composition of the feed [19] and they take up heavy metal ions [22,23] from aqueous solutions. Poly[(N-vinylimidazole)-co-(sodium styrenesulfonate)] hydrogels [24,25] have also several peculiar properties, for example, for some gel compositions dry discs swell up readily and then, spontaneously, they deswell and collapse.…”

Section: Introductionmentioning

confidence: 99%

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pH-dependence of the swelling capacity of poly(N-vinylimidazole) hydrogels

Molina

Gómez-Antón

Piérola

2002

Macromol. Chem. Phys.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

pH-dependence of the swelling capacity of poly(N-vinylimidazole) hydrogels

Molina

Gómez-Antón

Piérola

2002

Macromol. Chem. Phys.

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“…When this occurred, the sorption process was not passive diffusion of the solvent molecules into the void spaces of the network but included concomitant relaxation of the network segments that resulted from the advancing solvent front, leading to plasticization of the material and a large increase in volume. The generalized semiempirical equation used to describe the swelling kinetics was [21][22][23] …”

Section: Effect Of Swelling Medium Ph On Kinetic and Equilibrium Swelmentioning

confidence: 99%

Whey protein concentrate hydrogels as bioactive carriers

Gunasekaran

Xiao

Eleya

2005

J of Applied Polymer Sci

103

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Two sets of heat-induced hydrogels were prepared from whey protein concentrate (WPC), one set at a constant concentration [15% (w/v)] and varying pHs (pH 5.1-10.0) and the other set at a constant pH (10.0) and varying concentrations (12%, 15%, and 18%). At a given pH, the higher the protein concentration, the shorter was the gelation time and the larger were the equilibrium storage modulus (GЈ ϱ ) and failure stress. For a given protein concentration, the gelation kinetics and mechanical properties of WPC hydrogels were strongly pH dependent. The swelling behavior of WPC gels was studied at 37.5°C Ϯ 0.5°C. The equilibrium swelling ratio (SR) was at the minimum when pH of the swelling medium was close to the isoelectric point (pI) of the whey protein, and when the swelling medium pH was far from the pI (from 6.0 to 10.0), the SR increased. In particular, when the pH was higher than the pI, the swelling was highly pH sensitive. The higher the WPC concentration used in preparing the hydrogel, the lower was the SR. The controlled drug release properties of the WPC hydrogels were studied using caffeine as the model drug. Consistent with the swelling behavior of the gels, release was slower when the pH of the medium was lower (pH 1.8) than when it was higher (pH 7.5). The SR and the drug release rate decreased significantly when the gels were surface-coated with alginate.

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“…Protonation converts neutral polymers in polyelectrolytes showing particularly interesting effects [22][23][24][25] in which the roles of morphology and crosslinking are imbricated. In this work, both neutral and protonated PVI hydrogels were studied.…”

Section: Introductionmentioning

confidence: 99%

Discrimination of the roles of crosslinking density and morphology in the swelling behavior of crosslinked polymers: Poly(N‐vinylimidazole) hydrogels

Pacios

Piérola

2009

J of Applied Polymer Sci

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The degree of swelling (S) of crosslinked polymers depends on several variables whose individual contributions are difficult to be distinguished. The aim of this work is to determine the contributions of the morphology to S, discriminating them from the effect of the crosslinking density. Under usual conditions of synthesis, these two characteristics vary simultaneously but here, several samples of chemically crosslinked poly(N-vinylimidazole) having the same permanent crosslinking density (determined by DSC) and different porous morphologies (determined by SEM) were prepared. It was thus found that the variation of S with porosity, keeping constant the rest of variables, is strongly solvent dependent. Swelling in methanol is almost constant whereas for ethanol, deionized water, and aqueous HCl solutions, S depends on morphological features in a different way for each medium. It was concluded that S increases with inherent porosity and solvent effects arise from the counterbalance of such increment with the dependence of the polymer-solvent interaction parameter on the polymer volume fraction.

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Swelling kinetics of poly(N‐vinylimidazole‐co‐sodium styrenesulfonate) hydrogels

Cited by 39 publications

References 40 publications

pH-dependence of the swelling capacity of poly(N-vinylimidazole) hydrogels

pH-dependence of the swelling capacity of poly(N-vinylimidazole) hydrogels

Whey protein concentrate hydrogels as bioactive carriers

Discrimination of the roles of crosslinking density and morphology in the swelling behavior of crosslinked polymers: Poly(N‐vinylimidazole) hydrogels

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