Synthesis of functionalized polyisobutylenes using the propylene epoxide/TiCl4 initiating system
Abstract
In this paper, we report the synthesis of symmetric and asymmetric telechelic polyisobutylenes (PIBs). A PIB with a primary hydroxy head group and an allyl end group (HO–PIB–Allyl, Mn = 4300 g mol−1; Mw/Mn = 1.2) was synthesized by living carbocationic polymerization of isobutylene (IB) using propylene epoxide as an initiator and allyltrimethylsilane as a terminating agent. Thiol–ene click chemistry using 2-mercaptoethanol and 1,2-ethanedithiol yielded an asymmetric HO–PIB–SEt–OH (Mn = 4646 g mol−1; Mw/Mn = 1.18) and a symmetric HO–PIB–OH (Mn = 8594 g mol−1; Mw/Mn = 1.2) respectively. A symmetric allyl telechelic PIB (Mn = 8669 g mol−1; Mw/Mn = 1.2) was prepared by enzymatic transesterification of divinyl adipate with the primary hydroxy group of HO–PIB–Allyl.