Chain transfer with carbon tetrabromide in the polymerization of styrene
- 1 January 1971
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Transactions of the Faraday Society
- Vol. 67, 3046-3056
- https://doi.org/10.1039/tf9716703046
Abstract
Previously reported values of 1.36-2.7 at 60°C for the chain transfer constant Cs for styrene polymerization in the presence of carbon tetrabromide have been shown to be in error due to excessive extents of conversion. Most of the carbon tetrabromide is consumed by 0.5-0.7 % polymerization and subsequent reaction probably approximates to bulk polymerization. Restriction of the extent of conversion to 0.5 % gives an estimated value of 420±60 for Cs, which is independent of temperature. The activation energy and frequency factor for the chain transfer reaction of polystyrene radicals with carbon tetrabromide is 33 ± 7 kJ mol–1 and 9.2 × 109 1.mol–1 s–1 respectively. The effect on the freeze-dried polymer of precipitation in methanol has been investigated.Keywords
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