Abstract
Distearyl hydroxylamine has been developed as a polymer stabilizer, but the mechanism of action has not yet been clarified. The mechanism was investigated by evaluating the radical-scavenging potential. Distearyl hydroxylamine could better scavenge oxygen-centered radicals such as an alkoxy radical than carbon-centered radicals. The α,α-dimethylbenzyloxy radical scavenging ability (kinh = 5.8 × 104 dm3 · mol−1 · s−1) of distearyl hydroxylamine was considerably higher than that of BHT (kinh = 1.7 × 104 dm3 · mol−1 · s−1) or HALS NOH, but the radical scavenging number (n) of distearyl hydroxylamine was not so high as that reported previously. The high radical-scavenging ability of distearyl hydroxylamine seems to be based on the easier cleavage of the C–N bond of N,N-distearyl nitroxide radical derived from hydrogen abstraction by an alkoxy radical, compared with that of HALS NOH. A new radical scavenging mechanism of distearyl hydroxylamine is proposed based on the observations of electron spin resonance spectroscopy.
