On the nature of macroradicals formed upon radiolysis of aqueous poly(N-vinylpyrrolidone) solutions

Clelia Dispenza, Maria Antonietta Sabatino, Björn Dahlgren, Zois Tsinas, Clelia Dispenza, Mohamad Al-Sheikhly, Dianne L. Poster, James F. Wishart, Mats Jonsson

Risultato della ricerca: Articlepeer review

Abstract

In this work we have explored the nature of macroradicals formed upon radiolysis of aqueous poly(N-vinylpyrrolidone) (PVP) solutions using pulse radiolysis, density functional theory (DFT) and literature data. On the basis of literature data on site-specific kinetics of hydrogen abstraction from simple amides and spectra corresponding to specific radical sites on the same amides we have assessed the distribution of H-atom abstraction by •OH radicals from different positions on the pyrrolidone ring and the polymer backbone. Pulse radiolysis experiments performed at different doses per pulse and different PVP concentrations demonstrate that the H-abstracting radiolysis products are not quantitatively scavenged by the polymer when the dose per pulse exceeds ≈40 Gy. The implications of this are discussed in the context of radical-initiated crosslinking reactions. At a mass fraction of 0.1% PVP and doses per pulse ranging from 7 Gy to 117 Gy, the overall radical decay observed at 390 nm follows second order kinetics with rate constants on the order of 109 dm3 mol-1 s-1.
Lingua originaleEnglish
pagine (da-a)108900-108907
Numero di pagine7
RivistaRadiation Physics and Chemistry
Volume174
Stato di pubblicazionePublished - 2020

All Science Journal Classification (ASJC) codes

  • Radiation

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