Spin-labelled gels of poly(methyl acrylate)

✍ Scribed by Antal Rockenbauer; Mikael Lindgren; Masayoshi Tabata; Wu Yang

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 417 KB
• Volume: 29
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(93)90290-v

✦ Synopsis

Spin-labelled poly(methylacrylate) (PMA) was investigated by ESR both in the swollen and in the dried gel state. The polymerization was induced by y-irradiation; the spin-labelling was carried out by thermal treatment in the presence of 2,4,6-trichloronitrosobenzene. The labelling takes place both on the methine and the methylene carbons of the PMA chain resulting in a triplet and a six-line ESR spectrum respectively. For both radicals, the correlation time is of the order of 10-gsec in the swollen gel and I0 -s see in the dried gel. The temperature dependence of the ESR signal associated with the three-line radical and six-line radical could be analysed in terms of a diffusion model. The activation energies were determined as 23 and 19 kJ/mol, respectively. The radical structures and reactions are discussed.