Study of the morphology and kinetics of novel Ziegler–Natta catalysts for propylene polymerization

Abstract

ABSTRACT:The morphological and kinetic characteristics of novel Ziegler-Natta catalysts were studied. Catalysts were prepared by Borealis Polymers Oy using a new synthesis technique (emulsion technology). Video microscopy was used to study the growth of single catalyst particles during polymerization in the gas and liquid phases. The distribution of single particle activity was very narrow in the catalyst without external support and was rather broad in the the silica-supported catalyst. Video microscopy of molten polymer particles allowed observation of the process and degree of fragmentation of the catalyst particles. A correlation between the activation period during the initial stage of polymerization and catalyst fragmentation was found. Fragmentation was faster and more uniform with the catalyst without external support than with the silica-supported catalyst. Scanning electron microscopy provided information on morphology evolution and shape replication of the catalyst particles. With the catalyst without external support, good shape replication was observed, and compact and spherical particles were formed. With the silica-supported catalyst, shape replication was poor, and nonspherical porous polymer particle were formed. Modeling of the kinetics of propylene polymerization was done using a simple threestep reaction scheme neglecting mass and heat transport effects.

Evaluation of the Initial Stages of Gas‐Phase Ethylene Polymerizations with a SiO2‐Supported Ziegler–Natta Catalyst

“…A proprietary SiO 2 -supported Ziegler-Natta catalyst with a titanium content of 2.0 wt.-% was used for ethylene polymerization. This catalyst system is similar to the one used by Aboudd et al [35,36] and the reader is referred to those works for more information about the catalysts. Gas-phase ethylene polymerizations were carried out in a 1 cm 3 fixed-bed microreactor at different temperatures and partial pressures of ethylene and hydrogen.…”

“…Microscopy has been used by several research groups for in situ monitoring of homopolymerizations and copolymerizations reactions in the gas phase, mainly because of the non-destructive feature of this technique. [33] Recently, Abboud et al [34][35][36] employed videomicroscopy to follow the polymer particles melting obtained from heterogeneous catalysts. Laser scanning confocal fluorescence microscopy is also available for online monitoring of olefin polymerization.…”

Increased rubber content in high impact polypropylene via a sirius ziegler‐natta catalyst containing nanoparticles

“…21 A special feature of the Sirius technology is that no external catalyst support is added during catalyst synthesis, with the MgCl 2 that acts as support in the final catalyst being prepared in situ during catalyst preparation. Catalysts prepared using this technology have no measurable pore volume and a very low surface area (<5 m 2 ) according to Brunauer-Emmet-Teller (BET) analysis.…”

Sterilization of propylene/ethylene random copolymers: Annealing effects on crystalline structure and transparency as influenced by polymer structure and nucleation

“…Three series of experimental materials, all produced in a Borstar™ PP pilot plant unit with triethyl aluminium (TEAL) as co-catalyst and cyclohexyl methyl dimethoxysilane (CHMDMS, donor C) as external donor were investigated for this study: -$Series 'A' covers 7 EP random copolymers produced with a proprietary, non-commercial ZieglerNatta catalyst based on emulsion technology [21,22] -$Series 'B' covers 6 EP random copolymers produced with a conventional high yield 4 th generation Ziegler-Natta catalyst (C2; Avant ZN M1, LyondellBasell, Italy) having an ethylene content between 0 and 5 wt%. Visbreaking and additivation were the same as in series 'A'.…”