2,2,6,6-四甲基哌啶醇和2-羟基-4-辛氧基二苯甲酮对聚丙烯膜光稳定作用的协同效应

<正> 受阻胺(2,2,6,6-四甲基哌啶的衍生物)是近年来发展起来的一类新型高效光稳定剂,它和其它稳定剂并用时的稳定效果和作用机理,是重要的研究课题.Allen研究了Tinuvin 770(癸二酸双(2,2,6,6-四甲基哌啶)酯)和一系列抗氧剂同时添加到聚丙烯膜中时的效应,指出其中许多抗氧剂和Tin.770都有显著的反协同效应;他的研究还表明,

SYNERGISM OF 2,2,6,6-TETRAMETHYL-4-HYDROXY PIPERI- DINE AND 2,2,6,6-TETRAMETHYL-4-HYDROXY-PIPERIDINE- N-OXYL WITH 2-HYDROXY-4-OCTYLOXY-BENZOPHENONE (UV-531) IN PHOTO-STABLIZATION OF POLYPROPYLENE FILMS

The photo-stabilizing effect of 2, 2, 6, 6-tetramethyl-4-hydroxy-piperidine (TMP) and 2, 2, 6, 6-tetramethyl-4-hydroxy-piperidine-N-oxyl (TMPO) alone and with 2-hydro-xy-4-oetyloxy-benzophenone (uv-531) on polypropylene (PP) films has been investigated. Expermental results show that both TMP and TMPO. synergise with uv-531. It is shown also that the decrease in concentration of uv-531 obeys first-order kinetics in films containing uv-531 alone and with TMP and TMPO and the rate constants in cases of films containing uv-531 with TMP and TMPO are less than that of films containing uv-531 alone. From these facts it has been suggested that the reason of synergism of studied stabilizers consists mainly in that N-oxyls can scavenge active radicals produced in photooxidation of PP films and inhibite effectively the formation of carbonyl compounds and hydroperoxides and thus protect uv-531 from photo-destruction during the photo-oxidation of PP.