Decomposition of polypropylene hydroperoxide by hindered amines

Abstract

The hindered amine‐induced decomposition of polypropylene hydroperoxide was studied in the solid state and in the presence of a liquid solvent and the polymer was compared with model hydroperoxides. The high reactivity of the macrohydroperoxides appears to be related to the adjacent, hydrogen‐bonded hydroperoxide groups that occur in the polymer. The hindered amines are converted to nitroxides in the reaction via hydroxylamine intermediates. Amine‐induced decomposition of polypropylene hydroperoxide is faster in the absence of a liquid solvent for the amine than in the presence of the solvent, probably because of the strong amine‐hydroperoxide association that occurs in the solid state. The decomposition process in the solid state is sufficiently rapid for the reaction to contribute to the effectiveness of hindered amines in the light stabilization of polymers.

Photo-hydroperoxidation and grafting of polyoctenamer. Access to new polymeric-hindered amine stabilizers

“…High concensamples (15 min) in acetic acid/propane-2-ol with trations of double bonds in the polymer used resodium iodide and measuring the I 0 3 liberated by sulted in the production of associated hydroperox-UV spectroscopy at 360 nm. 6 The limiting viscosides in the close neighborhood of anthracene. The ity number of the polymer was determined in tolufollowing reactions lead to the production of hyene at 30ЊC using an Ubbelohde viscometer.…”

“…4,5 Anthracene was used as a sensitizer for production of singlet oxygen under 365 nm irradia-clic ring content. This rubber has a regular strucExtraction was performed by dipping the film containing the additives into methanol for 60 min at ture [{(CH 2 ) 6 {CH|CH{] n , with a double bond at every eight C-atom. The trans/cis ratio of laboratory temperature.…”

Photo-stabilizing efficiency of N-substituted hindered amines in polypropylene: Effects of processing conditions and exposure to a protonic acid

“…Prior to use, the commercial PPfilm employed (30/tm thickness, Profax resins, unoriented) was exhaustively Soxhlet extracted with acetone to remove processing additives. 5 For melt compounding, unstabilized PP-powder (Profax6301) and …”

Search for Unified Action Mechanism of Hindered Amine Light Stabilizers

“…The mechanism involves heterolytic or ionic decomposition proceeding trough the nucleophilic attack of a hydroperoxide on the lone pair of an amine nitrogen atom (Scheme 7). Homolytic decomposition through a similar nucleophilic reaction starting with the attack of a hydroperoxide on the lone pair has also been proposed (Scheme 8) 12) . Another mechanism is based on a reaction forming a complex of HALS and peroxide.…”