The inhibition of free radical-initiated polymerization of styrene by β-carotene (βC) and α-tocopherol (TOH) was studied by dilatometry. The polymerization was initiated by 2,2′-azobis(isobutyronitrile) at 50 °C in chlorobenzene and inhibited by βC and/or TOH. It was found that βC and TOH could efficiently inhibit the polymerization, either used individually or in combination, and a significant synergistic effect was observed when they were used in combination. It is proposed that retinal, which is the principal oxidation product of βC, may be involved in the synergistic inhibition reaction of βC and TOH. Copyright © 2002 John Wiley & Sons, Ltd.
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