Poly(propylene‐co‐ethylene) produced with a conventional and a self‐supported ziegler–natta catalyst: Effect of ethylene and hydrogen concentration on activity and polymer structure

Abstract

A novel self-supported emulsion-based catalyst and a conventional MgCl 2 -supported Ziegler-Natta catalyst were used in the copolymerization of propylene and ethylene under industrial conditions using triethyl aluminium as cocatalyst and dicyclopentyl dimethoxy silane as external donor. The effects of the concentration of ethylene and hydrogen on the polymerization behaviors and polymer properties were investigated. The combined effect of both ethylene and hydrogen increased the relative activity of the novel catalyst more than for the conventional catalyst. This trend was consistent with our earlier observed higher degree of dormancy, due to 2,1 insertions, found with the novel catalyst. More importantly, the work has uncovered that the self-supported catalyst incorporates ethylene in a more random fashion and produces copolymers with relatively narrow molecular weight distribution (MWD). These results in combination with polymer microstructure studies using Fourier transform infrared spectroscopy, 13 C-NMR spectroscopy, and differential scanning calorimetry all indicated that the novel catalyst has a narrower distribution of active site types than the conventional reference catalyst. The narrow composition of active site structures, the narrow MWD, and the random incorporation of ethylene into the polymer chain indicated that the emulsion-based catalyst possesses features that to a certain degree tend to be more indicative for a single-sitelike catalyst structure and behavior.

Heterophasic copolymers of polypropylene: Development, design principles, and future challenges

“…The design window of PP impact copolymers from both technological and economic perspectives is defined by the capabilities of the catalyst and the polymerization process that are used . These can support and compensate each other.…”

β-Nucleation of isotactic polypropylene: Chain structure effects on the effectiveness of two different nucleating agents

“…PP-H1 comes from a diluentslurry process involving multiple stirred tank reactors and is based on a 2 nd generation ZN1 catalyst with methyl-methacrylate as external donor. The ZN2 catalyst used for PP-H2 as well as for the random copolymers, PP-R1 and PP-R2, was a self-supported type from an emulsion process as described before [64], but with a non-phthalate internal donor and combined with dicyclopentyl dimethoxy silane (donor D) as external donor. The SSC used for PP-H3 is an asymmetric metallocene catalyst similarly heterogenized in an emulsion process.…”

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

“…This method is described elsewhere. 19 Scanning electron microscopy (SEM) was used to characterize the powder morphology. The equipment was FEI Quanta 200FEG with high resolution and field emission.…”

“…Despite the compact nature of the catalyst it has previously been shown to exhibit good polymer powder morphology and high activity during polymerization. [18][19][20] In this article, we describe the performance of a Sirius catalyst, which utilizes nanoparticles to create porosity in the homo PP matrix particle, for production of HiPP.…”