The free radical decomposition of polymethyl methacrylate and of polymethacrylic acid initiated by the photo-reduction of potassium ferricyanide additions

• Published in: Polymer science USSR 1977, Vol.19 (5), p.1127-1134
• Main Authors: Davydov, Ye.Ya, Pariiskii, G.B., Toptygin, D.Ya
• Format: Article
• Language: English
• ISSN: 0032-3950; 1878-268X
• DOI: 10.1016/0032-3950(77)90034-X

ESR and viscometry have been used to study the thermal conversions of the ∼CH 2C(CH 3)CH 2∼ macro-radicals which are produced in the polymethacrylic acid (PMA) and polymethyl methacrylate (PMM) during the photo-reduction of K 3Fe(CN) 6. The thermal decomposition of these radicals at sufficiently low temperatures (room and below) has been established to cause the effective destruction of the macromolecules. The kinetic curve of this radical decomposition in PMA in the 175–212°K range is stepwise in type; the minimum and maximum of the activation energy determined from it was found to be 13·0±1 and 16·1±1 kcal/mole respectively, and the log K 0-value (sec −1)=13·7±1. The thermal decomposition kinetics are described by a simple equation of first order at higher temperatures, E being 16·5 kcal/mole and log K 0 (sec −1) 13·1±1 in this case.