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Synthesis of functional water-soluble polymers
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Li, Muxiu (2013) Synthesis of functional water-soluble polymers. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b2722801~S1
Abstract
The objective of this work was to synthesise water-soluble polymers bearing
desirable functionality, particularly to improve water-solubility of phthalocyanines
by incorporation of hydrophilic polymers for personal oral care applications.
Prior to preparation of water-soluble polymers containing phthalocyanine, the second
chapter described the synthesis of ferrocenyl initiator for polymerisation of tert-butyl
acrylate by SET-LRP, followed by acidolysis of tert-butyl group yielding
poly(acrylic acid) containing ferrocenyl end group. The resulting polymer could be
used as the scale inhibitor for a potential oil drilling application, and further detected
by cyclic voltammetry due to the presence of the ferrocene end group.
The majority of the thesis is focussed on an investigation of novel approaches for
covalently attachment of water-soluble polymers to (copper or zinc) phthalocyanines.
The initial PEGylated CuPc complexes were obtained via DCC/EDC coupling
reactions, and the resulting blue powder showed excellent solubility in water;
however, it revealed a broad molecular weight distribution due to the presence of
mono-, di-, and tri- substitutions of PEG chains as confirmed by GPC analysis.
PEGylation of phthalocyanines were further improved via a combination of
Mitsunobu reaction and CuAAC “click” reaction. In this approach, the substituted
macrocycles were prepared from 4,5-bis-(4-hydroxyphenoxy)phthalonitrile as a
precursor. The final PEGylated CuPcs or metal-free Pcs with different PEG chain
lengths were prepared by two different routes. The incorporation of the (Cu)Pc core
with the polymer chain was confirmed and distinguished by THF-GPC equipped
with a PDA detector, and also showed an increase in hydrodynamic volume with
increasing the PEG chain length with a narrow dispersity remained.
PDMAEMA, as a dual responsive polymer was also introduced to ZnPc using a
core-first approach by a combination of ATRP and CuAAC reaction with sharing the
same CuBr/PMDETA catalyst, yielding the star-shaped water-soluble polymer. The
polymer solution represented tuneable LCSTs in range between 83 and 33 oC with
increasing the pH of the buffer solution from 7 to 10. The polymer was further
transformed into highly polyelectrolyte stars with ZnPc core by quaternization of the pendant amino groups with either methyl iodide or 1,3-propanesultone. The resulting
zwitterionic star after quaternized with propanesultone, ZnPc-PMEDSAH, exhibited
a UCST value 17 oC, compared with the quaternized salt, ZnPc-PMETAI with no
obvious phase transition observed. In addition, their optical properties and
aggregation behaviour in water were investigated by UV-Vis spectroscopy.
The final study involved the synthesis of water-soluble zinc phthalocyanines
conjugated to poly(galactose) by an arm-first approach. The well-defined protected
galactose oligomer arm was synthesised by SET-LRP with a desirable ω-chain end
as confirmed by MALDI-ToF MS analysis which were ready for postfunctionalisation.
Following a click reaction and deprotection of the acetal groups,
the isolated green powder achieved good water-solubility and emitted a sharp
fluorescent band at approximate 695 nm via excitation at 610 nm in DMF. The GPC
analysis also showed that a narrow molecular weight distribution remained after
deprotection and confirmed the presence of ZnPc core by the PDA detector.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QD Chemistry | ||||
Library of Congress Subject Headings (LCSH): | Water-soluble polymers, Polymerization | ||||
Official Date: | September 2013 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | Department of Chemistry | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Haddleton, David M.; Khoshdel, Ezat | ||||
Sponsors: | Unilever (Firm) | ||||
Extent: | xxiv, 199 leaves : charts. | ||||
Language: | eng |
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