Abstract
In this paper is described the precise synthesis of stereoregular polymethacrylates with end-functionality through stereospecific anionic polymerization in combination with functional initiators or terminators. A protected lithium amide, lithium N-benzyltrimethylsilylamide (BnTMSNLi), effectively initiated the anionic polymerization of methyl methacrylate (MMA) in the presence of ethylaluminum bis(2,6-di-tert-butylphenoxide) [EtAl(ODBP)2] to form syndiotactic (st)-PMMA with amine end-functionality. By using ethyl α-(chloromethyl)acrylate (T1) as a terminating agent, anionic polymerization of MMA with the aid of lithium trimethylsilanolate (Me3SiOLi) gave isotactic (it)-PMMA bearing acrylate-type C=C bonds at its terminating chain-end, while st-PMMA with the same chain-end structure was obtained by the use of EtAl(ODBP)2 in place of Me3SiOLi. The introduced acrylate-type C=C bonds could react with several kinds of thiols (Michael-type thiol-ene reaction) for further chemical modification. By a combination of the functional initiator, BnTMSNLi, and the terminator, T1, a heterotelechelic st-PMMA was also obtained, which could be doubly modified by the reaction with an isocyanate at the amine ends and a thiol with the C=C ends in one-pot.
