Reaction of hals in polypropylene during light exposure: Part 1‐iso‐octane as reaction model compound ‐

Abstract

The photo and thermal reactivity of nitroxyl radicals derived from di-,(oligo)meric hindered amine light stabilizers (HALS) on iso-octane, a model compound for polypropylene, was studied and compared to that of monomeric 2,2,6,6-tetramethyl-piperi -dine-N-oxyl (TEMPO). The exchange-interaction among >N-O. groups seems to affect only the thermal process.

Principles of Stabilization

“…ESR studies 62 show the possibility of free electron exchange between two nitroxyl groups placed in one molecule but this process does not seem to result in an increased ability to quench excited states. ESR studies 62 show the possibility of free electron exchange between two nitroxyl groups placed in one molecule but this process does not seem to result in an increased ability to quench excited states.…”

Testing Methods of Weathered Specimen

“…182,186,255,262,459,508,[516][517][518][519][520][521][522][523][524][525] GC and LC are usually interfaced with IR or mass spectroscopy, MS, which are qualitative detectors. 182,186,255,262,459,508,[516][517][518][519][520][521][522][523][524][525] GC and LC are usually interfaced with IR or mass spectroscopy, MS, which are qualitative detectors.…”

Thermolysis of a Tertiary Alkoxyamine. Recombination and Disproportionation of α-Phenethyl/Diethyl Nitroxyl Radical Pairs

“…Most TAA's reported previously were made by scavenging alkyl radicals with the isolable nitroxyl radical 2,2,6,6-tetramethylpiperidine-1-oxyl (Tempo). − ,,− A sufficient amount of 3 to study its chemistry was obtained by refluxing ethylbenzene (bp 136 °C) with di- tert -butyl peroxide and 2 . Although the yield was only 2.6% and column chromatography was required for purification, this unlikely looking synthesis of 3 proceeds in one step from inexpensive starting materials.…”