Study of macroradical reactivity by an electron paramagnetic resonance method

Abstract

The formation of macroradicals in the mechanical degradation of polymers gives the means for the direct kinetic determination of macroradical reactivity (reaction of the macroradicals with each other and with various low molecular substances). The free radical concentration was determined by means of EPR spectroscopy. With the aid of this method a study was made of the characteristic reactions such as removal of a hydrogen atom, addition, etc.

ESR Spectroscopy in Polymer Research

“…20. Decay curves of the polypropylene radicals: (e)300 produced by sawing, (0) produced by -y-irradiation1789) Fig.8.21. Decay curves of the polypropylene radicals formed by ballmilling: (0) in the presence of300 tetra-cyano-ethylene, (e) without free radical scavenger1789 ) 22.…”

“…Decay curves of the polypropylene radicals: (e)300 produced by sawing, (0) produced by -y-irradiation1789) Fig.8.21. Decay curves of the polypropylene radicals formed by ballmilling: (0) in the presence of300 tetra-cyano-ethylene, (e) without free radical scavenger1789 ) 22. Decay curves of polypropylene radicals formed by ballmilling: (0) under high vacuum 10-5 mm Hg and (e) in the presence of air1789 ) time a great number of free radicals (R·) attract electrons from triboelectric charges to form anions which have paired electrons and do not give ESR spectra: During the warming in the temperature range of 100-173 K, formation occurs of peroxy radicals ROO· from the anions and molecular oxygen:(8.6) …”

Electron spin resonance of polymers

“…Radical decay was followed up to T , but no kinetic treatment was presented. These authors have also stated that radicals produced by mechanical degradation of PMMA decay unimolecularly in a vacuum (34).…”