Burns, James A. (2011) Synthesis and characterisation of star polymers. PhD thesis, University of Warwick.

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Abstract

The objective of this thesis was to investigate the synthesis of well defined star polymers utilising
controlled radical polymerisation techniques for potential use as viscosity modifiers in Engine oils.
Recent developments in the characterisation of star polymers using multi-detector GPC was
investigated by first synthesising a series of star polymers using a core-first technique and ATRP.
Core-first initiators were used to initiate the polymerisation of PMMA star polymers which were
then analysed using multi-detector GPC. Using Zimm and Stockmayer theory the functionality, f,
(number of arms) of the resultant star polymer was estimated over the MWD of the polymer using
GPC with in-line viscometry. A variation in functionality with molecular weight was seen, which
disagrees with the limited other literature in the field.
The GPC technique was then used to determine the functionality of star polymers synthesised using
RAFT polymerisation and an arm-first technique to yield star PMMA with a high Mw and PDI. Varying
the divinyl species and the ratio of [crosslinker] to [macroRAFT agent] was seen to control the
functionality and molecular weight of the star formed. Varying the amount of monomer present at
the point of crosslinking was seen to have little contribution to the star polymer formed when the
ratio of [MMA] to [macroRAFT agent] was under 10.
Switching RAFT agents from 2-cyanoprop-2yl dithiobenzoate (CPDB) to an oil soluble
trithiocarbonate, for the RAFT polymerisation of long chain alkyl methacrylate gave hybrid
polymerisation kinetics. Through a monomer feed system, controlling the ratio of [monomer] to
[RAFT agent] throughout the reaction, polymers of narrow PDI were synthesised and subsequently
crosslinked to form oil soluble star polymers.
Applying the techniques used for the synthesis of core-crosslinked star polymers using RAFT
chemistry to different area of polymer chemistry, glycopolymers; a series of linear mannose and
galactose bearing glycopolymers have been synthesised. Trimethylsilyl propargyl methacrylate (TMSPgMA) has been polymerised to varying DP, between 20 and 200, using CPDB as the RAFT
agent. Subsequent deprotection of the propargyl groups has yielded a series of alkyne bearing linear
polymers. Using a CuAAC reaction to "click" mannose and galactose azide to the polymer scaffolds
yielded well defined sugar bearing polymers. A P(TMSPgMA) macroRAFT agent was crosslinked using
different crosslinkers to giving a high molecular weight, alkyne bearing, star polymer.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Polymerization, Oils and fats -- Viscosity
Official Date:	December 2011
Dates:	Date Event December 2011 Submitted
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Haddleton, David M. ; Smith, Timothy
Extent:	xxxv, 253 leaves : ill., charts
Language:	eng

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