Emulsifier-free, organotellurium-mediated living radical emulsion polymerization (emulsion TERP) of methyl methacrylate with dimethyl ditelluride as the catalyst

Emulsifier-free, organotellurium-mediated living radical emulsion polymerization (emulsion TERP) of methyl methacrylate (MMA) using poly(methacrylic acid) (PMAA)–methyltellanyl (TeMe) (PMAA30-TeMe) (degree of polymerization of PMAA, 30) was carried out at 60 °C with 1000 rpm stirring. The emulsion TERP of MMA did not successfully proceed with maintaining a living manner because of a low chain transfer rate constant relative to propagation rate constant. Moreover, even in the coexistence of (TeBu)2, the emulsion TERP of MMA also did not proceed with living nature. On the other hand, it in the coexistence of (TeMe)2 proceeded with good control/livingness. The difference was caused by the different in the solubility in water between (TeBu)2 and (TeMe)2. Because (TeBu)2 is difficult to dissolve in the aqueous phase, it did not work as a catalyst in the aqueous phase, resulting in a homogeneous nucleation. On the other hand, because (TeMe)2, which is more hydrophilic than (TeBu)2, works as an efficient catalyst in the aqueous phase, resulting in the self-assembly nucleation.