Synthesis of polystyrene-block-poly(iso-butyl vinyl ether) by dinuclear half-metallocene catalyst and atom transfer radical polymerization

Abstract

The synthesis of polystyrene-block-poly(iso-butyl vinyl ether) by using the combination of metallocene catalyst and atom transfer radical polymerization (ATRP) has been tried. This synthetic method takes advantages of both metallocene catalyst to form stereoregular polymer with high activity and ATRP with the controlled molecular weights and low polydispersity. The recent dinuclear half-sandwich complexes of titanium with xylene bridge, [Ti(η⁵-cyclopentadienyl)Cl₂L]₂-ortho, meta-[CH₂-C₆H₄-CH₂] (L = Cl, L = O-2,6-iPr₂C₆H₃ ) were successfully synthesized. These catalysts were characterized by ¹H NMR, ¹³C NMR and elemental analysis. Copolymers have been characterized by using gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR). The collected copolymers have got narrow molecular weight distribution (≤1.8) and the improvement of stereoregularity (racemo dyads, r, are from 45 % to 56 %).