Change search
ReferencesLink to record
Permanent link

Direct link
Study of ethylene/propylene polymerization, using a 4th generation Ziegler-Natta catalyst: Effect of external donor and feed ratio on polymerization
KTH, School of Chemical Science and Engineering (CHE).
2012 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

A fourth generation multiple site Ziegler-Natta catalyst was used to synthesize ethylene and propylene homo-and copolymers in the presence of hydrogen. This type of catalysts produce polymers with broader molecular weight distribution (MWD), chemical composition distribution (CCD) and stereoregularity than other coordination polymerization catalysts since it has more than one active site.

The ratio of propylene/ethylene was varied to study its effect on polymer microstructure. In addition, by having two different electron donors, namely diisopropyldimethoxysilane (P) and dicyclopentyldimethoxysilane (D), the molecular weight distribution (MWD) and stereospecificity of the synthesized polymers were examined.

The polymer samples were characterized using 13C-NMR and high-temperature gel permeation chromatography (GPC). Using the 13C-NMR data, the triad distribution for the copolymers and also the isotactic triad distribution for homo-polymers were calculated.

The effects of electron donors on different feed ratios of ethylene and propylene in the synthesis were investigated. Co-polymer produced with D-donors showed higher isospecificity and also higher content of ethylene in the final polymer. In contrast, polymers produced using with P-donor showed lower polydispersity indices (PDI), and had higher contents of propylene in final polymer. In addition, the “Deconvolution method” was applied to GPC data in order to determine the number of sites on the Ziegler-Natta catalyst; which showed that 4 active site types were adequate to explain the molecular weight distributions.

Place, publisher, year, edition, pages
2012. , 53 p.
Keyword [en]
Ziegler-Natta catalysts, Electron Donor, Copolymerization, Polyolefins
National Category
Engineering and Technology
URN: urn:nbn:se:kth:diva-147523OAI: diva2:730241
Available from: 2014-06-27 Created: 2014-06-27 Last updated: 2014-06-27Bibliographically approved

Open Access in DiVA

fulltext(1735 kB)1575 downloads
File information
File name FULLTEXT01.pdfFile size 1735 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
School of Chemical Science and Engineering (CHE)
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 1575 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 125 hits
ReferencesLink to record
Permanent link

Direct link