This thesis examines the relationship between the microstructural and the mechanical properties of poly-(propylene-ethylene) bi-phasic copolymers. The copolymers investigated covered a comonomer content ranging between 4 and 23 percent ethylene. Nine grades were considered, with variables such as the melt flow index, the degree of crystallinity, the molecular weight distribution and the effect of a nucleating agent being examined. These copolymers have been characterised in order to gain a better understanding of the interrelationship between the morphological structure and their physical, mechanical, thermal and thermo-mechanical properties. The toughness of the copolymers can be enhanced at low temperatures by increasing the ethylene content, at the expense of a loss in stiffness. A study of the microstructure using the scanning electron microscope indicates that a good balance between these two properties can be achieved through a uniform size and spatial distribution of the ethylene-propylene rubber particles within the polypropylene homopolymer matrix. The transmission electron microscope shows the ethylene-propylene rubber (EPR) to be agglomerates of smaller particles, with some crystallinity within the EPR being evident.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/19804 |
| Date | January 1999 |
| Creators | Mange, Siyabonga |
| Contributors | Marcus, Kashif |
| Publisher | University of Cape Town, Faculty of Engineering and the Built Environment, Centre for Materials Engineering |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Master Thesis, Masters, MSc |
| Format | application/pdf |
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