Poly(Alkyl Methacrylate-co- Acrylic Acid)

313 Pages·2015·13.9 MB·English

by  Sarah Canning

Poly(Alkyl Methacrylate-co-
Acrylic Acid) Copolymers of
Varying Architecture for
Improved Adhesion

Sarah Louise Canning

A Thesis submitted for the Degree of Doctor of Philosophy

Department of Chemistry, University of Sheffield
March 2015

Acknowledgements
I would firstly like to thank my supervisory team, Prof. Steve Rimmer and Prof. Mark
Geoghegan at the University of Sheffield and Dr Trevor Wear, Dr Stuart Reynolds and
Dr Jon Morgan at Domino UK Ltd for all their help, support and guidance throughout
this project. Thanks also go to the rest of the R&D team at Domino for being so
welcoming to me.
Domino UK Ltd and the EPSRC are gratefully acknowledged for providing financial
support for the project.
To everyone in the Chemistry Department at the University of Sheffield, I’m grateful
for their assistance and for making the department such a friendly place to work. I
particularly want to thank Melanie Hannah for her technical assistance and support. I
am grateful to Richard Bottomley for allowing me to borrow equipment from the
teaching labs, to Rob Hanson for his help with chromatography, to Sue Bradshaw for
her assistance with NMR, and to Jenny Louth for elemental analysis. Thank you also to
Pete Farran and Nick Smith for their storekeeping and footballing excellence, and to
Pauline Bould for being a cheerful face every morning.
I am very grateful to Dr Svet Tsokov in the EM Department for training me to use the
TEM and for his continued advice, and to Chris Hill who assisted with the SEM
imaging.
I must thank Dr Ann Terry and Dr Steve King, instrument scientists at the ISIS facility,
for their assistance with the SANS experiments. I am also extremely grateful to Prof.
Patrick Fairclough for his help with fitting the SANS data.
I’m thankful to all the members of the Geoghegan group past and present, especially
Jason Zhang who trained me on the AFM with utmost patience.
I must also thank the past and present members of F floor and the Rimmer group for
their advice, support and friendship over the past three and a half years, particularly
Laura Platt, Laura Shallcross, Simon Finnegan and Pavintorn (Mew) Teratanatorn.
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I also want to thank the undergraduate students who have worked with me on summer
placements, Sammi Hassan, Joe Ferner and Natalie Paul; I appreciate their hard work
and enthusiasm.
Thanks to Lizzy Jones and Vicki Cunningham for being excellent friends and
housemates, I’m glad we’ve experienced this journey together.
Thank you to Nathan Rutland for his support, patience and understanding (not to
mention top banter!) You made the writing process much less painful than I expected. I
hope I can return the favour when your turn comes.
Finally I want to thank my family for their continuous support and encouragement
throughout my studies and my entire life. I want to dedicate this thesis to my
grandmother Pam Penhale, who will always be an inspiration to me.

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Abstract

Amphiphilic copolymers composed of hydrophilic polyacrylic acid segments and
hydrophobic poly(alkyl methacylate) segments were targeted as adhesion-promoting
additives for use in printing inks. Methyl, butyl and lauryl methacrylates were chosen to
vary hydrophobicity. Initially, a phase transfer-catalysed backbone functionalisation and
a reversible addition-fragmentation chain transfer (RAFT)-controlled grafting step were
employed to form graft copolymers, although polyacrylic acid homopolymer was also
produced. The lauryl methacrylate synthesis proved more difficult due to the steric
effect of the long alkyl chain. Branched and linear poly(alkyl methacrylate-acrylic acid)
copolymers were then synthesised using RAFT, in either a one-pot polymerisation,
producing random copolymers, or a two-step procedure forming block copolymers.
Molecular weights of close to 20 000 g mol-1 were achieved, with methacrylate:acrylic
acid ratios close to 1:1, as targeted. Branching was confirmed through calculation of
Mark-Houwink parameters using GPC with viscometric detection, and a 13C NMR
method was developed to identify block or random monomer sequence distribution.
Due to their amphiphilic nature, the copolymers were found to self-assemble in water to
form macromolecular structures. These varied according to architecture, monomer
distribution, and hydrophobicity of the methacrylate segment. Small angle neutron
scattering was used to study the copolymers in a range of solvent systems. Whilst
Gaussian coils were formed in d-THF and self-assembled spheres or multi-lamellar
micelles were formed in D O, the copolymers were found to aggregate into fractal
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structures in intermediate solvency conditions. The behaviour of the copolymers when
coated on polyolefin substrates was studied by contact angle measurements, and the
random materials created more polar surfaces compared to the segmented analogues. A
force spectroscopy technique showed potential for accurate comparison of copolymer
adhesion. Ink formulations containing the butyl methacrylate copolymers jetted well on
both thermal inkjet and drop on demand printers. Adhesion was assessed using industry
standard tests, and better overall performance was observed for the branched
copolymers.

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List of Abbreviations

α Mark-Houwink parameter
γ surface energy of liquid
L
γ surface energy of liquid-solid interface
LS
γ surface energy of solid
S
AA acrylic acid
AFM atomic force microscope
AIBN azobisisobutyronitrile
ACVA 4,4’-azobis (4-cyanovaleric acid)
ANOVA analysis of variance
ATRP atom transfer radical polymerisation
BMA butyl methacrylate
BN α-bromonaphthalene
CDCl deuterated chloroform
3
CIJ continuous inkjet
CRP controlled radical polymerisation
CTA chain transfer agent
Ð dispersity
DB degree of branching
d-DMSO deuterated dimethyl sulfoxide
d-EtOH deuterated ethanol
D fractal dimension
f
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D O deuterium oxide
2
DOD drop on demand
D degree of polymerisation
p
d-THF deuterated THF
EG ethylene glycol
g’ contraction factor
GPC gel permeation chromatography
HB highly branched
HD 1,2-hexanediol
HDPE high density polyethylene
I(Q) scattering intensity
IV, [η] intrinsic viscosity
K Mark-Houwink parameter
LDPE low density polyethylene
LMA lauryl methacrylate
MMA methyl methacrylate
M number-average molecular weight
n
M weight-average molecular weight
w
nMA alkyl methacrylate monomer
NIP non-impact printing
NMP nitroxide mediated polymerisation
NMR nuclear magnetic resonance
Q scattering vector
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PAA polyacrylic acid
PALS phase analysis light scattering
PE polyethylene
PnMA poly(alkyl methacrylate) (n = M methyl, B butyl or L lauryl)
PNIPAM poly(N-isopropyl acrylamide)
PP polypropylene
P(Q) form factor
PTC phase transfer catalysis
RAFT reversible addition-fragmentation chain transfer polymerisation
RB repeat units per branch
R radius of gyration
g
RI refractive index
SANS small angle neutron scattering
SCVP self condensing vinyl polymerisation
SEM scanning electron microscopy
SLD scattering length density
S(Q) structure factor
tBA t-butyl acrylate
TBAB tetrabutyl ammonium bromide
TEM transmission electron miscroscopy
TIJ thermal inkjet
VBC 4-vinylbenzyl chloride

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