4-tcrt-butyl styrene

Fig. 3.11. Reduced viscosity plots comparing diblock poly(tert-butyl styrene-co-sodium styrene sulfonate), D5-TBS-SS(Na), with random poly(tcrt-butyl styrene-co-sodium styrene sulfonate), R5-TBS-SS(Na), and homopolymer poly(sodium styrene sulfonate). Reprinted with permission from Ref. 7...

The formation of considerable amounts of acetone and tcrt-butyl alcohol during the decomposition of 2,2-bis(tcrt-butylperoxy)butane in styrene indicates that the rates of 3-scission and H-abstraction are competitive with addition to the styrene double bond. Niki and Kamiya [167,168] are in agreement that considerable H-abstraction between terf-butoxy radicals and PS takes place especially at high polymerization temperatures (125 °C). However, p-scission rate is in disagreement with Moad. As mentioned earlier, Moad found that the rate of vinyl addition by tert-butoxy radicals is 76 times faster than P-scission... 

Bon and co-workers were the first to publish a successfiil attempt toward TEMPO-mediated LRP in emulsion (109). This first work was far from optimal, since it only worked in seeded emulsion polymerization, and temperatures above 100°C were required to obtain a dynamic equilibrium between dormant and active species. NMP improved quite significantly with respect to its applicability in emulsion pol5unerization when the above-mentioned developments led to polymerization temperatures below 100°C. Notable in this respect was the work by Charleux and co-workers, who employed)V-tcrt-butyl-iV-(l-diethylphosphono-2,2-dimethylpropyl)nitroxide as the mediating nitroxide for the LRP of styrene and butyl acrylate in emulsion (110,111). 

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