Synthesis of polyolefin- block-polystyrene through sequential coordination and anionic polymerizations.

ABSTRACT Two representative bulk polymers, polyolefin (PO) and polystyrene (PS), were molecularly connected to form PO- block-PS by sequentially performing coordination and anionic polymerizations in one pot. Ethylene/1-octene copolymerization was performed using a typical ansa-metallocene catalyst, rac-[Me2Si(2-methylindenyl)]2ZrCl2, in the presence of (benzyl)2zinc to grow PO-chains at the Zn site. Anionic styrene polymerization was subsequently performed using nBuLi·(tmeda) (tmeda, N, N, N′, N′-tetramethylethylenediamine) initiator to consecutively grow PS-chains at the Zn site. The composition and the molecular weight of the PO-blocks were controllable depending on the feed amounts of 1-octene and (benzyl)2zinc (1-octene fraction: ∼20, ∼40 wt %; PO- Mw, 77,000-174,000) and the PS-block size was also controlled (PS- Mn, ∼21,000) with the complete conversion of the styrene monomer. Formation of block copolymers was evident in the GPC curves, TEM images, and strain-stress curves. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3110-3118 [ABSTRACT FROM AUTHOR]