Hydroxyl-radical-induced reactions of poly(vinyl methyl ether): a pulse radiolysis, EPR and product study in deoxygenated and oxygenated aqueous solutions

Janik, Ireneusz; Ulański, Piotr; Hildenbrand, Knut; Rosiak, Janusz M.; Sonntag, Clemens von

doi:10.1039/b004777p

Cited by 35 publications

(28 citation statements)

References 45 publications

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“…• OH reaction with low-molecular-weight models of water-soluble polymers such as poly(vinyl alcohol) [39], poly(vinyl methyl ether) [48][49][50], or poly(acrylic acid) [51][52][53] indicate that these reactions can be considered as controlled by diffusion. Our value of k(…”

Section: Discussionmentioning

confidence: 99%

Reaction of a low‐molecular‐weight free radical with a flexible polymer chain: Kinetic studies on the OH + poly(N‐vinylpyrrolidone) model

Bartoszek

Ulański

Rosiak

2011

Int J of Chemical Kinetics

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This work addresses the issue of kinetics of diffusion-controlled reactions of small radicals with macromolecules in solution. Attack of pulse-generated hydroxyl radicals on poly(N-vinylpyrrolidone)-PVP-chains of various molecular weight in water was used as the model reaction. Pulse radiolysis with spectrophotometric detection was applied to determine the rate constants by competition kinetics. The rate constant depends both on polymer concentration and on its molecular weight. In dilute solutions, a distinct dependence of the rate constant on the molecular weight is observed. In the studied range of molecular weight, the values of reaction radius, calculated using Smoluchowski equation on the basis of experimental kinetic data, are very close to the radius of gyration of polymer coils. We believe that radius of gyration, as an easily determined parameter, could possibly serve for predicting rate constants of diffusion-controlled reactions of polymers with low-molecular-weight compounds in dilute solutions. With increasing polymer concentration and thus increasing spatial overlap of polymer coils the dependence of the rate constant on the molecular weight fades away, and the rate constant values increase with increasing concentration toward the value determined for low-molecular-weight model of PVP. Most steep increase approximately coincides with the

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Section: Discussionmentioning

confidence: 99%

Reaction of a low‐molecular‐weight free radical with a flexible polymer chain: Kinetic studies on the OH + poly(N‐vinylpyrrolidone) model

Bartoszek

Ulański

Rosiak

2011

Int J of Chemical Kinetics

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“…[30] The vinyl ether does not undergo a radical initiated polymerization. [31] Most of the investigations were focused on cross-linking of PVME by irradiation of its aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

Temperature‐Sensitive Hydrogel Pattern by Electron‐Beam Lithography

Schmidt

Mönch

Arndt

2006

Macro Materials & Eng

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Summary: Cross‐linking of water‐soluble polymers by high‐energy irradiation provides a clean method for the synthesis of hydrogels. Some applications of stimuli‐sensitive polymers need different patterns in the micro‐ and submicrometer range on a supporting material. A dry layer of poly(vinyl methyl ether) on a Si‐wafer was cross‐linked and patterned by irradiation with the electron beam of a modified electron microscope. The patterns in the micro‐ and submicrometer range show good adhesion on the supporting material without adhesion promoter. The deformation and the elastic behavior of the pattern were tested by AFM. The formed gel structures were sensitive against changes in environmental condition. This offers a wide range of applications.

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“…The chemistry underlying radiation-induced crosslinking of water-soluble polymers has been studied in detail. [22][23][24][25][26] In brief, highly reactive water-derived species and polymer macromolecule radicals are formed in the aqueous solution by irradiation. Fast reactions of some of the intermediates with macromolecules (mainly through H-atom abstraction from the polymer by OH radicals) lead to the formation of polymer radicals in most cases.…”

Section: Dsc Analysismentioning

confidence: 99%

Investigation on the formation mechanisms of hydrogels made by combination of γ‐ray irradiation and freeze‐thawing

Yang

Liu

Chen

et al. 2008

J of Applied Polymer Sci

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Hydrogels based on poly(vinyl alcohol) (PVA)/water-soluble chitosan (ws-chitosan)/glycerol were prepared by g-ray irradiation, freeze-thawing, and combination of g-ray irradiation and freeze-thawing, respectively. The influence of freeze-thawing cycles, the irradiation doses, and the sequence of freeze-thawing and irradiation processes on the rheological, swelling, and thermal properties of these hydrogels was investigated to evaluate the formation mechanisms of hydrogels made by combination of irradiation and freeze-thawing. For hydrogels made by freeze-thawing followed by irradiation, the physical crosslinking is destroyed partially while chemical crosslinking is formed by irradiation. However, the chemical crosslinking density reduces with the increase of freeze-thawing cycles. Hydrogels made by irradiation followed by freeze-thawing bear less degree of physical crosslinking with the increase of irradiation dose for the increased chemical crosslinking density. It is found that these hydrogels own larger swelling capacity and better transparent appearance than those made by freeze-thawing followed by irradiation. Moreover, the former hydrogels have larger mechanical strength than the latter at low freeze-thawing cycles.

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Hydroxyl-radical-induced reactions of poly(vinyl methyl ether): a pulse radiolysis, EPR and product study in deoxygenated and oxygenated aqueous solutions

Cited by 35 publications

References 45 publications

Reaction of a low‐molecular‐weight free radical with a flexible polymer chain: Kinetic studies on the OH + poly(N‐vinylpyrrolidone) model

Reaction of a low‐molecular‐weight free radical with a flexible polymer chain: Kinetic studies on the OH + poly(N‐vinylpyrrolidone) model

Temperature‐Sensitive Hydrogel Pattern by Electron‐Beam Lithography

Investigation on the formation mechanisms of hydrogels made by combination of γ‐ray irradiation and freeze‐thawing

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