Regiochemistry‐Aligned Copolymerization of Propylene with p ‐Methylstyrene and 1,4‐Diviny­lbenzene Using an ansa ‐Metallocene Catalyst

Copolymerization of propylene with styrenic α‐olefin monomers is rare with C 2 ‐symmetric ansa ‐metallocene‐type catalysts, which are the dominant single‐site catalysts for isospecific propylene polymerization. This makes it difficult to obtain compositionally narrow‐distributed reactive polypropylene with isotactic stereoregularity ( i PP) bearing benzyl and styryl moieties, which are important precursors for i PP functionalization. In this paper, rac ‐CH 2 (3‐ t ‐Bu‐1‐Ind) 2 ZrCl 2 is paired with methylaluminoxane (MAO) and used in copolymerization of propylene with p ‐methyl­styrene ( p ‐MS) and 1,4‐divinylbenzene (DVB). Due to the unified primary regiochemistry of the catalyst toward both propylene and the styrenic monomers, both copolymerizations are viable, with the incorporation of the styrenic monomers not disastrously decreasing the catalyst activity. The fingerprint primary–primary consecutive sequences of propylene and p ‐MS/DVB are clearly identified by 13 C NMR. As high as 1.37 mol% of p ‐MS and 0.93 mol% of DVB are incorporated into i PP at fairly high catalyst activities. It is noteworthy that DVB is incorporated with a selective mono‐enchainment mode, leaving i PP with pendant styryl groups on the linear backbone. Both the i PP/ p ‐MS and i PP/DVB copolymers show narrow molecular weight distributions (<3), indicating a single‐site characteristic of the copolymerizations. Overall, copolymerization of propylene with p ‐MS and DVB with a C 2 ‐symmetric ansa ‐metallocene catalyst is made possible by unification of the insertion regiochemistry of the comonomers.