Abstract
To clarify whether polyamines scavenge alkyl (carbon-centered) and peroxy (oxygen-centered) radicals, we analyzed their effects on the kinetics of polymerization of methyl methacrylate (MMA) induced by 2, 2'-azobisisobutyronitrile (AIBN, a RØ radical) and benzoyl peroxide (BPO, a PhCOOØ radical) under nearly anaerobic conditions. Stoichiometric factors (n; number of free radicals trapped by one mole of antioxidant moiety) were determined by the induction period method. The n value for polyamines (putrescine, spermidine and spermine) was 0.1-0.7, whereas that for conventional synthetic antioxidants, BHA and BHT, was about 2. These n values were not different between the AIBN and BPO systems. The n value for polyamines declined in the order spermine>spermidine >putrescine. The Kinh/Kp value for polyamines (20-115) was greater than that (4-7) for BHT or BHA. Radical-scavenging activity largely depends on the stoichiometric factor of antioxidants rather than their effects on initial rate of polymerization, a rate of propagation. Polyamines may scavenge alkyl or peroxy radicals derived from polyunsaturated fatty acids in biological systems.
Footnotes
- Received September 20, 2004.
- Revision received February 1, 2005.
- Accepted February 15, 2005.
- Copyright© 2005 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved