Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: An instrument, named solution crystallization analysis by laser light scattering (SCALLS), that measures
the solution melting and crystallization of polymers in solution was developed further in this study. The
instrument was tested in a theoretical study to evaluate the Flory-Huggins relationship of melting point
depression in solution of copolymers. It was found that the solvent interaction parameter for
propylene/higher 1-alkene copolymers, with low comonomer content is dependent on the comonomer type.
It was also showed that the melting point depression is dependent on both the type and amount of
comonomer included in the copolymer. The instrument was further developed to include a total of three
lasers with different wavelengths. Initial problems with laser interference was rectified by the introduction
of dichroic mirrors to direct the laser light to the relevant detectors and broad pass filters in front of the the
detectors to ensure that only the relevant laser light passes through. For homogenous polypropylene samples
it was found that even though a slower cooling rate increases the relative peak temperatures as well as the
relative temperature differences between the peaks, detail in the peak profiles is the same for the faster
cooling rate. The subsequent heating analysis does show that there is a definite dependence on the cooling
rate. The ZNPP-4 sample shows that the appearance of a shoulder in the heating analysis becomes more
defined as a peak if the preceding cooling analysis is slower. Complex impact-polypropylene samples,
differing only in the amount of ethylene were analysed and even small differences between samples were
detected. The possible application of the SCALLS instrument was investigated. It was proven that the
instrument can be used as a screening method for prep-TREF to determine the fractionation temperatures. / AFRIKAANSE OPSOMMING: 'n Instrument, genoem oplossing kristallisasie-analise deur laser lig verstrooiing (SCALLS), wat die
smeltpunt asook die kristallisasie temperatuur in oplossing kan meet is verder ontwikkel in hierdie studie.
Die Flory-Huggins verhouding oor die smeltpunt depressie in oplossing van ko-polimere is ondersoek in ‘n
teoretiese studie. Daar is bevind dat die oplossing interaksie parameter vir propileen/hoër 1-alkeen
kopolimere, met lae ko-monomeer inhoud is afhanklik op die ko-monomeer tipe. Dit is ook getoon dat die
smeltpunt depressie afhanklik is van beide die tipe en hoeveelheid ko-monomeer in die ko-polimeer. Die
instrument is verder ontwikkel om 'n totaal van drie lasers met verskillende golflengtes in te sluit.
Aanvanklike probleme met laser inmenging is reggestel deur die bekendstelling van dichromatiese spieëls
wat die laser lig na die regte ooreenstemmende detektor rig en filters voor die detektors verseker dat net die
relevante laser lig die detektor bereik. Vir homogene polipropileen monsters is dit bevind dat selfs al is die
analises gedoen teen ‘n stadiger afkoelings tempo wat lei tot ‘n verhoging in die piek kristallisasie
temperatuur asook die relatiewe temperatuur verskille tussen die lasers, bly die detail in die piek profiele
dieselfde as wat gesien word met ‘n vinniger afkoelings tempo. Die daaropvolgende verhitting analise toon
dat die analise definitief afhanklik is op die voorafgaande afkoelings analise. Die ZNPP-4 monster toon dat
die voorkoms van 'n skouer in die verwarming-analise word meer gedefinieerd en ‘n piek word gevorm soos
die voorafgaande afkoelings tempo verlaag. Komplekse impak-polipropileen monsters, wat net verskil in die
hoeveelheid etileen inhoud is geanaliseer en verskille is bepaal. Moontlike toepassings van die SCALLS
instrument is ondersoek. Dit is bewys dat die instrument gebruik kan word om die fraksionering temperature
vooraf te bepaal vir prep-TREF.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/71751 |
| Date | 12 1900 |
| Creators | Brand, Margaretha |
| Contributors | Van Reenen, Albert J., Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 1 v. (various pagings) : ill. |
| Rights | Stellenbosch University |
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