Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: This study concerns the copolymerization of propylene with l-heptene. The
percentage of l-heptene used as co-monomer in the polymerization reactions was
varied from 5% to 20% in order to compare a variety of polymers with different
percentages of comonomer incorporated. A variety of different catalysts were used
for these polymerizations.
Two metallocene catalysts were used: (A) the isospecific catalyst, rae-
[ethylene bis(l-indenyl)]zirconium dichloride (rac-Et(Ind)2ZrCh2) and (B) the
silylene-bridged catalyst, rac-Me2Si(2-MeBenz[ e]Ind)zZrCh2. Methylaluminoxane
(MAO) was used as cocatalyst for these two metallocene catalysts. Another series of
polymerization reactions was done using a Ziegler-Natta catalyst, namely
TiCb/AlEt3/Si02.
Characterization of the copolymers included usmg high temperature gel
permeation chromatography (HTGPC) for molecular mass and molecular mass
distributions, differential scanning calorimetry (DSC) and dynamic mechanical
analysis (DMA) to investigate the thermal and mechanical properties of the
copolymers, nuclear magnetic resonance spectroscopy (NMR) for information
concerning the microstructures of the copolymers and crystallization analysis
fractionation (CRYSTAF) to investigate the short chain branching of the copolymers.
Comparative studies were done on the different catalysts and the polymer
properties. The synthesized polymers were also compared with copolymers of
propylene with l-hexene and l-octene. / AFRIKAANSE OPSOMMING: Hierdie studie behels die kopolimerisasie van propileen met I-hepteen. Die
persentasie van I-hepteen wat as komonomeer in die polimerisasie-reaksies gebruik
is, is van 5% tot 20% gevarieer. 'n Verskeidenheid van verskillende kataliste is
gebruik vir hierdie polimerisasies.
Twee metalloseenkataliste is gebruik: (A) die isospesifieke katalis, rae-
[etileen bis(l-indeniel)]zirconium dichloried (rac-Et(lnd)2ZrCh2) en (B) die silileengebrugde
katalis, rac-Me2Si(2-MeBenz[e]Ind)2ZrCh2. Metielaluminoksaan (MAO) is
as ko-katalis gebruik saam met bogenoemde twee metalloseenkataliste. 'n Ander
reeks polimerisasie reaksies is gedoen waarin 'n Ziegler-Natta katalis gebruik is as
aktiverende katalis, naamlik TiCi)/ AlEt3/Si02.
Die karakterisering van die kopolimere sluit in: hoë temperatuur gel
deurlatings chromatrografie (HTGPC) vir molekulêre massa en molekulêre massa
verspreidings, differensiële skandering kalorimetrie (DSC) en dinamiese meganiese
analisering (DMA) om sodoende die termiese en meganiese eienskappe van die
polimere te ondersoek, kern magnetiese resonans spektroskopie (KMR) vir inligting
in verband met die mikrostrukture van die kopolimere en kristallisasie analise
fraksioneringstegniek (CRYSTAF) om die kort-kettingvertakkings van die
kopolimere te ondersoek.
Vergelykende studies IS op die verskillende katalisatore en die
polimeereienskappe gedoen. Die gesintetiseerde polimere is ook met kopolimere van
propileen met I-hekseen en l-okteen vergelyk.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52334 |
| Date | 12 1900 |
| Creators | Lutz, Marietjie |
| Contributors | Van Reenen, A. J., Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Sciences. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 162 pages : illustrations |
| Rights | Stellenbosch University |
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