Triethylborane and methyl vinyl ketone as a bicomponent transfer agent forthe polymerisation of styrene

The polymerisation of styrene in the presence of methyl vinyl ketone (MVK) and triethylborane (BEt3) was studied. The mixture of these two compounds w as found to form a bicomponent complex that functions as a transfer agent f or growing polystyryl radicals (C-T = 0.7; benzene 60 degrees C). The analy sis of the polymer chains formed by MALDI-TOF-MS showed that they were fitt ed with CH2-CH3 and CH2-CH2-C(O)-CH3 as end groups which obviously emanated from MVK and BEt3. In contrast, no such transfer occurred on using each of them as single compound.