An introduction is given to the background theory and
scientific literature of the major subject areas of interest in
this thesis, namely the chemistry of free radical and anionic
polymerisation, molecular weight control in each type of polymerisation,
polymerisation reactors, computer simulation of
polymerisation processes and polymer characterisation by gel
permeation chromatography.
A novel computer model has been devised, based on the
analysis of the polymerisation process in terms of the reaction
extent of each reactant and the use of generation functions
to describe the concentration of living and dead polymeric
species, for the free radical, solution polymerisation of methylmethacrylate
in a CSTR. Both heat and mass balance expressions
have been described. Conversion, Mn and Mw were monitored.
To test the model a reactor was designed and constructed.
A detailed description of the reactor and the experimental
conditions used for the validation of the model are given.
The results of these studies are presented and excellent agreement
is shown between model predictions and experiments up to 30%
conversion for Mn
w and % conversion.
A similar study is described for the anionic polymerisation
of styrene in tetrahydrofuran as solvent, in a CSTR. In this
work the computer model becomes 'stiff' when realistic rate
constants are introduced in the kinetic expressions.
Experimental difficulties were encountered in obtaining
reproducible results in the anionic work. A new approach of
using 'scavengers' as protecting agents for the living chains
is described. A scavenger was successfully employed in the
preparation of block copolymers using a tubular reactor.
Block copolymerisation, in addition to providing a means of
checking the number of the 'living' chains inside the reactor,
is of interest in its own right.
All the experimental findings are discussed in relation
to the currently accepted views found in the scientific
literature.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/3792 |
| Date | January 1976 |
| Creators | Bourikas, N. |
| Contributors | Johnson, A.F. |
| Publisher | University of Bradford, Postgraduate School of Studies in Polymer Science. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
Page generated in 0.0024 seconds