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Free-Radical Termination Kinetics Studied Using a Novel SP-PLP-ESR Technique

✍ Scribed by Michael Buback; Mark Egorov; Thomas Junkers; Elena Panchenko

Publisher: John Wiley and Sons
Year: 2004
Tongue: English
Weight: 171 KB
Volume: 25
Category: Article
ISSN: 1022-1336
DOI: 10.1002/marc.200400050

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✦ Synopsis

Abstract

Summary: A novel method for measuring termination rate coefficients, k~t~, in free‐radical polymerization is presented. A single laser pulse is used to instantaneously produce photoinitiator‐derived radicals. During subsequent polymerization, radical concentration is monitored by time‐resolved electron spin resonance (ESR) spectroscopy. The size of the free radicals, which exhibits a narrow distribution increases linearly with time t, which allows the chain‐length dependence of k~t~ to be deduced. The method will be illustrated using dodecyl methacrylate polymerization as an example.

Two straight lines provide a very satisfactory representation of the chain‐length dependence of k~t~ over the entire chain‐length region (c~R~ = radical concentration).

magnified imageTwo straight lines provide a very satisfactory representation of the chain‐length dependence of k~t~ over the entire chain‐length region (c~R~ = radical concentration).

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Termination Kinetics of Dibutyl Itaconat

Termination Kinetics of Dibutyl Itaconate Free-Radical Polymerization Studied via the SP–PLP–ESR Technique

✍ Michael Buback; Mark Egorov; Thomas Junkers; Elena Panchenko 📂 Article 📅 2005 🏛 John Wiley and Sons 🌐 English ⚖ 158 KB

## Abstract Summary: The termination kinetics of dibutyl itaconate (DBI) bulk polymerization was studied via SP–PLP–ESR single pulse–pulsed laser polymerization with time‐resolved detection of free‐radical concentration by electron‐spin resonance, at temperatures between 0 and 60 °C. As is characte