Photostabilizing activity of N-acylated hindered amine

The influence of the acyl groups of N‐acylated hindered amine on the photostabilization of polymers was discussed. The effects of the N‐acyl derivatives of 4‐benzoyloxy‐2,2,6,6‐tetramethylpiperidine (6) in the photostabilization of polypropylene were compared. Although the stabilizing effects of all the N‐acyl derivatives were lower than that of the N‐oxyl derivative (7), N‐acryloyl (4) and N‐benzoyl (5) derivatives showed higher effects than that of parent NH 6. To discuss the stabilizing mechanism of N‐acylated hindered amine, the reaction of N‐acylated hindered amine with model hydroperoxide (tert‐butyl hydroperoxide) was carried out at an elevated temperature (132°C). N‐Acylated hindered amine decomposed tert‐butyl hydroperoxide more rapidly than corresponding secondary hindered amine, and changed into the parent secondary amine.