Pounder, Ryan J. (2010) The synthesis and ring-opening polymerisation of novel cyclic esters from malic acid. PhD thesis, University of Warwick.

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Abstract

The work in this thesis is directed towards the preparation of cyclic ester
monomers using malic acid as a renewable resource. Their subsequent controlled
ring-opening polymerisation (ROP) to yield functionalised poly(ester)s is studied
and application in micellar self-assembly reported.
Chapter 1 reviews the many synthetic strategies that have been employed in the
preparation of functional glycolides, lactides, ε-caprolactones, δ-valerolactones
and β-propiolactones. Their subsequent polymerisation and applications are also
discussed.
Chapter 2 describes the improved synthesis of 3-(S)-
[(benzyloxycarbonyl)methyl]- and 3,6-(S)-[di(benzyloxycarbonyl)methyl]-1,4-
dioxane-2,5-diones, BMD and malide respectively, from L-malic acid. Controlled
organocatalytic ROP of BMD realised functional poly(glycolic acid-co-benzyl α-
malate)s (PBMD) with the choice of initiator proving important in determining
the resulting molecular weight. Successful hydrogenolysis of these poly(glycolic
acid-co-benzyl α-malate)s yielded hydrophilic poly(glycolic acid-co-α-malic
acid)s (PGMA) with subsequent degradation studies in H2O observing complete
degradation after six days.
In Chapter 3, the synthesis of 5-(S)- and 5-(R)-[(benzyloxycarbonyl)methyl]-1,3-
dioxolane-2,4-dione (L-malOCA and D-malOCA respectively) from L- and Dmalic
acid respectively is reported. ROP of malOCA with a range of pyridine
based catalysts enabled the synthesis of functional poly(benzyl α-malate)s
(PBMA). Mechanistic studies revealed the formation of several side products that
were eliminated via judicious choice of catalyst and column chromatography.
Subsequent hydrogenolysis realised hydrophilic poly(α-malic acid)s (PMA) with
degradation studies in H2O observing complete degradation after 10 days.
Chapter 4 reports the synthesis of novel amphiphilic PEO-b-PBMA block
copolymers by the ROP of L-malOCA or D-malOCA from PEO macroinitiators
with subsequent self-assembly realising polymeric micelles. Variation in both
size dimensions and stability of the micelles through changes in both the
hydrophobic and hydrophilic block lengths and their relative ratios was
demonstrated. The self-assembly of an equimolar mixture of homochiral PEO-b-
P(L-BMA) and PEO-b-P(D-BMA) resulted in the formation of stereocomplexed
polymeric micelles.
Chapter 5 provides a summary of the findings in chapters 2 – 4 with chapter 6
providing the corresponding experimental data.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Esters -- Synthesis, Malic acid, Ring-opening polymerization
Official Date:	August 2010
Dates:	Date Event August 2010 Submitted
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Dove, Andrew
Sponsors:	Engineering and Physical Sciences Research Council (EPSRC)
Extent:	xxix, 250 leaves : ill., charts
Language:	eng

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