Show simple item record

dc.contributor.authorMaafa, Ibrahim 21:50:12 (GMT) 21:50:12 (GMT)
dc.description.abstractChain shuttling polymerization with dual catalysts has introduced a new class of polyolefin called olefin block copolymers (OBCs). The Dow Chemical Company developed this new material in 2006 with a chain shuttling agent used to exchange living and dormant chains between two single-site catalysts reversibly. One catalyst may produce a soft/amorphous ethylene/-olefin block due to its high reactivity ratio towards α-olefin insertion, while the other catalyst makes a hard/semi-crystalline ethylene/-olefin block due to its low -olefin reactivity ratio. The soft block provides elastomeric properties, whereas the hard block works as a physical crosslink to connect the elastomeric blocks. Characterization of these novel materials is challenging because there are no analytical methods that can measure the distribution of blocks in OBCs. A mathematical model that can describe the detailed microstructure of these products is, therefore, an important step towards understanding how different polymerization conditions and kinetic parameters affect their microstructure. The main objective of this thesis is to develop such detailed models for semi-batch and continuous stirred tank reactors (CSTR). Starting from the polymerization mechanism generally accepted for chain shuttling polymerization, we developed two different mathematical models to predict OBC microstructures made under different conditions. The first and simpler model uses population balances and the method of moments to predict chain length and composition averages for the overall (whole) OBC and for populations with different number of blocks. The second, and more complex model, uses dynamic Monte Carlo techniques to predict complete distributions of chain length and chemical composition. The simulations described in this thesis show that OBCs have complex, multiblock structures, that depend strongly on several polymerization kinetic parameters, reactor conditions, and reactor modes of operation. As these conditions change, number average chain lengths, chemical compositions, average number of blocks, and block distribution among the OBC populations are also affected, and possibly the application properties of these advanced polyolefins. The models proposed herein allow us to quantify the trends of this microstructural changes, and hopefully can help researchers design OBCs with better controlled molecular architectures.en
dc.publisherUniversity of Waterlooen
dc.subjectChain shuttling polymerizationen
dc.titleMathematical Modeling of Chain Shuttling Polymerizationen
dc.typeDoctoral Thesisen
dc.pendingfalse Engineeringen Engineeringen of Waterlooen
uws-etd.degreeDoctor of Philosophyen
uws.contributor.advisorSoares, Joao
uws.contributor.advisorSimon, Leonardo
uws.contributor.affiliation1Faculty of Engineeringen

Files in this item


This item appears in the following Collection(s)

Show simple item record


University of Waterloo Library
200 University Avenue West
Waterloo, Ontario, Canada N2L 3G1
519 888 4883

All items in UWSpace are protected by copyright, with all rights reserved.

DSpace software

Service outages