Patent ID: 8829116

Claim:
A method for producing an AB block copolymer with controlled polydispersity index, which comprises the following steps: 1) reaction, in the presence of at least one free radical initiator, of a reaction mixture comprising a compound of formula (I) where R 1 to R 4 , independently of one another, are each hydrogen, an alkyl radical, cycloalkyl radical or an aralkyl radical, each of which is unsubstituted or substituted, or a substituted or unsubstituted aromatic hydrocarbon radical, with the proviso that R 1 and R 2 or R 3 and R 4 , in pairs in each case, are one alkyl, cycloalkyl, aralkyl, or a functional group which, in conjugation with the C—C double bond in the formula (I), has a multiple bond between a carbon atom and a heteroatom, and another aralkyl which is a substituted or unsubstituted aromatic hydrocarbon having 6 to 18 carbon atoms, and an ethylenically unsaturated monomer A to obtain a macroinitiator; and 2) reaction, at a temperature of 45° C. or above, of a reaction mixture comprising an ethylenically unsaturated monomer B and, independent from that of step 1), a compound of formula (I) and the macroinitiator of step 1) in solvent(s) to obtain the AB block copolymer; wherein the weight ratio of the compound of formula (I) to the macroinitiator in step 2) is at least 1:1500 to 1:5.