A range of strategies exist for the production of polyolefin block copolymers with well-defined morphologies for the compatibilization of immiscible blends; however, high sensitivity to impurities and use of expensive transition-metal catalysts limit their economic viability. An alternative method is the solvent-free coupling of dislike polymers using peroxides and multifunctional coagents. This technique, however, does not distinguish between a blend of gelled homopolymers and the intended copolymer. The use of a solution-based approach, like the one described in this report, for the radical-mediated coupling of polyolefins with dislike polymers allows for the full
characterization of the copolymer without the formation of gel.
A one- and two-step synthesis for the coupling of two homopolymers in solution is
demonstrated using triallyl trimesate. The one-step approach produced a copolymer in low yields due to the differences in reactivity between the homopolymers. The
two-step synthesis consisted of the solvent-free grafting of the coagent to the less
reactive polymer, followed by coupling in solution with the other polymer. Though
this technique demonstrated improved yields over that of the one-step approach, the overall yields were limited due to the dilution effects of the high solvent levels
needed for comiscibility. The coupling of polyethylene with poly(ethylene oxide) had
a maximum graft yield of 9.5%, whereas the coupling between polypropylene and a
thermoplastic polyolefin elastomer was negligible.
It was found that the grafting of allylic ester coagents to polyethylene results in an
uneven graft distribution. Given enough peroxide and coagent, the material will
reach its gel point where there is a small, high molecular weight population with a
disproportionately high graft content, while the remaining chains contained a modest concentration of bound coagent. Furthermore, a survey of the effectiveness of several common coagents in the radical-mediated crosslinking of polyethylene was investigated where it was found that allylic coagents had a greater contribution to the
crosslink density of the resin than vinyl coagents. / Thesis (Master, Chemical Engineering) -- Queen's University, 2008-05-06 19:37:13.916
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/1201 |
| Date | 08 May 2008 |
| Creators | Kaufman, Michael Steven |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | 775370 bytes, application/pdf |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
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