Bimodal/Broad Polyethylene Prepared in a Disentangled State

Disentangled broad/bimodal polyethylene with an inverted distribution of short chain branches (SCBs) was synthesized with a supported hybrid catalyst. Poly­[styrene-co-(acrylic acid)]- (PSA-) coated SiO₂ particles were used to support the hybrid catalysts. The PSA was coated on SiO₂-supported VCl₃ catalyst. Then, Fe­(acac)₃/2,6-bis­[1-(2-isopropylanilinoethyl)]­pyridine was immobilized onto the PSA layer. It was demonstrated that the Fe­(acac)₃/2,6-bis­[1-(2-isopropylanilinoethyl)]­pyridine catalyst prepared linear polyethylene with a low molecular weight (MW) and C4–C22 α-olefin. Meanwhile, this α-olefin could be used as the comonomer for VCl₃ to prepare high-MW polyethylene with SCBs. Hence, broad-MW-distribution polyethylene (MWD = 120) with an inverted distribution of SCBs was obtained from only one monomer (ethylene). Interestingly, this is the first time that the synthesized polyethylene was reported to exhibit a disentangled state. The isothermal kinetics of crystallization based on the Avrami and Tobin methods was studied to obtain details about the evolution of the disentangled state during the polymerization process.