Synthesis of polyethylene and polypropylene containing fluorene units in the side chain

Copolymerizations of ethylene or propylene and allyl monomers containing 9-fluorenyl group, diallyl-di-9-fluorenylsilane (DAFS), 9,9-diallylfluorene (DAF), and 9-allylfluorene (AF), were investigated with various zirconocene catalysts using methylaluminoxane as a cocatalyst. The bridged zirconocene catalysts, especially a syndioselective catalyst, showed a higher reactivity for all the comonomers than the nonbridged catalysts. DAFS was mainly incorporated into the polymer chain via cyclization insertion, whereas DAF was copolymerized via both 1,2- and cyclization insertions. Cyclization selectivity, ratio of cyclized insertion unit, of DAF in the copolymerization with propylene was higher than that in the copolymerization with ethylene. Copolymerization with AF yielded low-molecular weight copolymer because of frequent chain transfer reaction. Optical properties of the propylene based-copolymers were investigated by UV-vis and photoluminescence spectroscopy, and absorption- and emission-derived from fluorenyl groups were detected in the copolymers.