Synthesis of aromatic diamino-functionalized dimethylsiloxane oligomers and macromonomers

Summary

Methods to synthesize dimethylsiloxane oligomers and macromonomers with aromatic diamino function were studied. Telechelic oligomers having 4-aminophenyl groups on both ends of the molecule(1) were synthesized by the reaction of 4-[N,N-bis(trimethylsilyl)amino]phenyllithium with α,ω-dichlorooligodimethylsiloxane. Reaction of the lithium reagent with methyltrichlorosilane followed by methanolysis and successive hydrolysis gave methylbis(4-aminophenyl)silanol. Reaction of the silanol with oligodimethylsiloxane with mono-dimethylchlorosilyl function at one end of the molecule gave dimethylsiloxane oligomers having methylbis(4-aminophenyl)silyl function at one end of the molecule(2).

Protection of the amino groups of bis(4-aminophenyl)methane as bis(trimethylsilyl)amino group, metalation of methylene group by butyllithium-N,N,N′,N′-tetramethylethylenediamine (TMEDA), followed by the reaction with mono-dimethylchlorosilyl-functionalized oligodimethylsiloxanes gave oligodimethylsiloxanes having bis(4-aminophenyl)methyl function at one end of the molecule(3).

Polydimethylsiloxane macromonomers having bis(4-aminophenyl)methyl function were obtained by end-capping the living end of the polymerization of hexamethylcyclotrisiloxane(D₃) by lithium bis[4-{bis(trimethylsilyl)amino}phenyl]methide with trimethylchlorosilane and removal of the protecting group.