一些氮氧自由基和受阻胺化合物对单重态氧的猝灭能力及其与光稳定作用的关系

本工作测定了一系列稳定氟氧自由基( )化合物及一些受阻胺光稳定剂对单重态氧(¹O₂)的猝灭速率常数(k_q^1O₂),发现不同结构的 对¹O₂的猝灭能力很接近,但它们对聚丙烯(PP)膜的光稳定作用却相差很大。四甲基哌啶醇(TMP)及其衍生物对¹O₂的猝灭能力远不如相应的五甲基哌啶醇(PMP)及其衍生物,但前者对PP的光稳定能力却胜于后者。这说明在对聚合物的光稳定作用中, 和受阻胺光稳定剂对¹O₂的粹灭作用不占重要地位,也说明¹O₂在PP的光氧化过程中很可能不是主要因素。

THE QUENCHING ACTION TOWARDS 1O2 OF SOME NITROXYL RADICALS AND HINDERED AMINES AND THEIR PHOTOSTABILIZING EFFICIENCIES

The rate constants for the quenching of singlet oxygen by a series of nitroxyl radicals and some hindered amines were determined. It wa found that the abilities of nitroxyl radicals with different structures for quenching singlet oxygen are very similar but their photostabilizing efficiencies are remarkably different. The quenching efficiencies of tetramethyl piperidinol and its derivatives are much more lower than that of pentamethyl piperidinol and the corresponding derivatives, but the photostabilizing efficiencies of the former are better than that of the latter. It shows that the quenching action towards ¹O₂ is not important during photostabiliza-tion of PP film by nitroxyl radicals and hindered amines. It would also imply the little contribution of singlet oxygen to photooxidation of PP film.