Anionic polymerization initiators and polymers therefrom

A method for preparing a chain-extended lithiated thioacetal solution, the method comprising:

• (i) preparing a lithiated thioacetal by reacting an initiator precursor compound with an organolithium compound, where the initiator precursor compound is defined by the formula
• where R is selected from C1 to C6 trialkyl-silyl groups, C1 to C20 alkyl groups, C4 to C20 cycloalkyl groups, C6 to C20 aryl groups, thienyl, furyl, and pyridyl groups;
• and R may optionally have attached thereto any of following functional groups:
• C1 to C10 alkyl groups, C6 to C20 aryl groups, C2 to C10 alkenyl groups, C3 to C10 non-terminal alkynyl groups, ethers, tert-amines, oxazolines, thiazolines, phosphines, sulfides, silyls, and mixtures thereof;
• where R1 is selected from the group consisting of C2 to C8 alkylene groups and where X is selected from the group consisting of S, 0 and NR, wherein R is as defined above, and may optionally have attached thereto any of the above identified functional groups to thereby produce a lithiated thioacetal having the general formula
• where R is selected from C1 to C6 trialkyl-silyl groups, C1 to C20 alkyl groups, C4 to C20 cycloalkyl groups, C6 to C20 aryl groups, thienyl, furyl, and pyridyl groups;
• and R may optionally have attached thereto any of following functional groups:
• C1 to C10 alkyl groups, C6 to C20 aryl groups, C2 to C10 alkenyl groups, C3 to C10 non-terminal alkynyl groups, ethers, tert-amines, oxazolines, thiazolines, phosphines, sulfides, silyls, and mixtures thereof;
• where R1 is selected from the group consisting of C2 to C8 alkylene groups and where X is selected from the group consisting of S, 0 and NR, wherein R is as defined above, and may optionally have attached thereto any of the above identified functional groups;
• and
• (ii) chain extending the lithiated thioacetal by polymerizing monomer including conjugated diene monomer, optionally together with vinyl aromatic monomer, to form a polymeric or oligomeric segment having at least 3 and less than 125 repeat units.