On the Nature of Macroradicals Formed upon Radiolysis of Aqueous Poly(N-­?vinylpyrrolidone)Solutions

Published

April 2, 2020

Author(s)

Richard D. Holbrook, Clelia Dispenza, Maria Antonietta Sabatino, Natascia Grimaldi, Bjorn Dahlgren, Mohamad Al-Sheikhly, James F. Wishart, Zois Tsinas, Mats Jonsson

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/pulse exceeds 40 Gy. The implications of this are discussed in the context of radical-­‐ initiated crosslinking reactions. At a 0.1 wt% PVP and doses per pulse ranging from 7 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.

Citation

Journal of Radiation Research

Pub Type

Journals

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Keywords

poly(N-vinyl pyrrolidone), pulse radiolysis, density functional theory, macroradicals, nanogels

Citation

Holbrook, R. , Dispenza, C. , Sabatino, M. , Grimaldi, N. , Dahlgren, B. , Al-Sheikhly, M. , Wishart, J. , Tsinas, Z. and Jonsson, M. (2020), On the Nature of Macroradicals Formed upon Radiolysis of Aqueous Poly(N-­?vinylpyrrolidone)Solutions, Journal of Radiation Research, [online], https://doi.org/10.1016/j.radphyschem.2020.108900 (Accessed April 25, 2024)