Vinyl-and Al-Terminated PEs

Entry FI catalyst Activity3 (kg mmol 1 h 1) Mw (xlO 3) MJMn Vinyl endc (%) 

Conditions 25 °C, atmospheric pressure, 5 min, ethylene gas feed 100 L h , catalyst 0.5 pmol, MAO 0.625 mmol as Al, toluene 250 mL akg polymer per mmol catalyst per h bDetermined by GPC 

Ethylene pressure studies have revealed a first-order dependence on ethylene for both the rate of chain propagation and the rate of chain transfer. This polymerization behavior together with X-ray analyses and DFT calculations has provided strong support for (1-11 transfer to an incoming monomer, which is responsible for the production of vinyl-terminated PEs. The calculations thus suggest that the catalysts disfavor (I-11 transfer to the Zr metal because of the extreme instability of the Zr hydride species that is produced in such a chain transfer process. 

The isopropyl group discourages P-H transfer, leading to the exclusive formation of Al-PEs. The Al-PEs can be readily transformed to a variety of functionalized PEs and to PE-based and polar polymer-based block and graft copolymers, using established methods. The selective synthesis of vinyl- and Al-terminated PEs with Zr-FI catalysts shows the critical importance of the substituent on the imine-N for polymerization catalysis. 

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K. Matoishi, K. Nakai, N. Nagai, H. Terao, T. Fujita, Value-added olefin-based materials originating from FI catalysis production of vinyl- and Al-terminated PEs, end-functionalized PEs, and PE/polyethylene glycol hybrid materials. Catal. Today 164, 2-8 (2011). doi 10.1016/j. cattod.2010.11.078... 

Heptaetiiyldec-9-enyl POSS monomer, 18, is a terminal a olefin monomer that has been employed by Tsuchida et al. to incorporate POSS moieties into polyolefins. Copolymers of tiiis monovinyl POSS monomer with ethene and propene (Fig. 12) were synthesi2ed vising different methyMumoxane-activated metallocene catalysts. POSS comonomer incorporation levels between 17 and 25 wt % were achieved, depending on wliich catalyst was used in the copolymerization. Incorporation of 25 wt % (1.2 mol %) of the vinyl-POSS 18 into the ethylene copolymer, 20, lowered the melting temperature by 18°C versus that of polyethene (PE). The thermal stability in air of vinyl-POSS 18/ethylene copolymer (0.7 mol % POSS) and 18/propylene copolymer... 

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