Characterization of MAO‐Modified Silicas for Ethylene Polymerization

Abstract

A series of methylaluminoxane (MAO)-modified PQ and EP 12 silicas, calcined at 110, 250, and 450 C, were prepared.The resulting MAO-modified supports were characterized by a set of complementary techniques: Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), small angle X-ray scattering (SAXS), and thermal gravimetric analysis (TGA). The Al/Si ratios of the MAO-modified PQ and EP12 silicas were in the ranges of 0.19-0.27 wt % and 0.17-0.30 wt %, respectively. MAO-modified silicas were used in the polymerization of ethylene using an Et 2 IndZrCl 2 catalyst. The MAO-modified PQ silica showed higher activity in comparison to the MAO-modified EP12.

Group 4 permethylindenyl complexes for slurry-phase polymerisation of ethylene

“…This MAO-modified silica has been well characterised and documented as a solid support for the immobilisation of single-site olefin polymerisation pre-catalysts. 5,8,18,[34][35][36] Complex immobilisation was achieved according to a literature procedure. 8 The complexes A, B, 4 and 6 were immobilised onto the three inorganic solid supports discussed (sMAO, LDHMAO and SSMAO), with an [Al]0:[Zr]0 ratio of 200:1.…”

Synthesis of zirconocene complexes and their use in slurry-phase polymerisation of ethylene

“…Precontacting the silica surface with MAO was reported to increase catalyst loadings. [21][22][23][24] The use of layered double hydroxides (LDHs), a class of anionic clays consisting of positively charged Brucite-like layers with weakly bound anions intercalated between them, as catalyst supports for olen polymerisation has been recently reported by the O'Hare group. [25][26][27] Heat treatment of MAO for a prolonged period was reported to increase polymerisation activity of up to 25%.…”

Synthesis, characterisation and ethylene polymerisation performance of silyl bridged peralkylated bis(indenyl) zirconocenes

“…[15,17] Impregnation of MAO, forming MAO modified silica (SSMAO), is required in order to activate the support. [10,15,[18][19][20][21] Recently, aqueous miscible organic layered double hydroxides (AMO-LDHs), a class of anionic clays consisting of positively charged Brucite-like layers with weakly bound anions intercalated between them, activated with MAO (LDHMAO), have been reported as catalyst supports for olefin polymerisation. [10,22,23] AMO-LDH supports are simple to synthesise on a large scale, more cost-effective than silica and show no evidence of reactor fouling or catalyst leaching, making them viable options for industrial processes.…”