MODEL-BASED DESIGN OF REACTION CONDITIONS FOR
SEGMENTED COPOLYMER SYNTHESIS BY COMBINING
STEP- AND CHAIN-GROWTH POLYMERIZATION
Lies De Keer,1 Thomas Gegenhuber,3 Paul H.M. Van Steenberge,1 Anja S. Goldmann,3
Marie-Françoise Reyniers,1 Christopher Barner-Kowollik,2,3 Dagmar R. D’hooge1,4
67TH CANADIAN CHEMICAL ENGINEERING CONFERENCE, EDMONTON, 22-25 OCTOBER 2017
1Laboratory for Chemical Technology (LCT), Ghent University
2School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT)
3Preparative Macromolecular Chemistry, Karlsruhe Institute of Technology (KIT)
4Centre for Textile Science and Engineering (CTSE), Ghent University
POLYMER CONJUGATION
Functional groups within polymer backbone:
Conjugation of macromolecular building blocks
Applications: e.g. introducing automated degradability in polymer chains
Research questions:
• adjustable segment length?
• synthesis strategy?
• reaction conditions ?
=> model-based design
2 PHASE SYNTHESIS STRATEGY
bifunctional ortho-methyl
benzaldehyde (AA)
bisfumarate bearing a
trithiocarbonate group (BB)
2) Chain-growth polymerization:
RAFT polymerization
1) Step-growth polymerization:
light-induced Diels-Alder reaction
MULTI-SCALE MODELING STRATEGY
D’hooge D.R. et al. Prog. Polym. Sci. 2016 58, 59
Derboven et al. Macromolecules 2015, 48, 492D’hooge et al. Macromol. React Eng. 2013, 7, 362
SOLUTION METHODS
5 5
Chain position (-)
Macromolecular structural detail
Model com
ple
xity
Van Steenberge P.H.M. et al. Macromolecules 2011, 44, 8716
Van Steenberge P.H.M. et al. Macromolecules 2012, 45,8519.
Van Steenberge P.H.M. et al. Chem. Eng. Sci. 2014, 11, 185
D’hooge D.R. et al. Polym. Chem. 2015, 6, 7081.
Derboven P. et al. Macromol. Rapid Commun. 2015, 36, 2149
D’hooge D.R. et al. Prog. Polym. Sci. 2016, 58, 59
Chain
num
ber
(-)
Log (molar mass)
w(l
ok
gm
ola
rm
ass
)
KINETIC MONTE CARLO METHOD
Composite binary trees
Van Steenberge P.H.M. et al. Chem. Eng. Sci. 2014, 11, 185 Brandao A.L.T. et al. Macromol. React Eng. 2015, 9, 141
OUTLINELight-induced step-growth polymerization
Experimental observations
Theoretical framework
Rate coefficients in view of design
Design step-growth precursor toward high molar masses
Chain extension by RAFT polymerization
Experimental observations
Theoretical framework
Rate coefficients in view of design
Design toward microstructural control
Conclusions
EXPERIMENTAL OBSERVATIONS
photoenolR = H, Ph
Gegenhuber et al. Macromolecules 2017 50, 6451
Main:
Monomer stability
Side:
THEORETICAL FRAMEWORK AND RATE COEFFICIENTS
kmain via small molecule study
ModelExperiment
kself,AA via monomer stability test
Experiment Model
r = 𝑁𝐴,0
𝑁𝐵,0
DESIGN STEP-GROWTH PRECURSOR TOWARD HIGH MOLAR MASSES[AA]0=[BB]0=0.02 mol L-1Equimolar conditions, r =
𝑁𝐴,0
𝑁𝐵,0= 1
No high molar mass chains
𝑋𝑤 =1 + 𝑝𝐴1 − 𝑝𝐴
[AA]0=0.07 mol L-1; [BB]0=0.02 mol L-1Off-stoichiometric conditions, r = 𝑁𝐴,0
𝑁𝐵,0= 1.75
𝑋𝑤 =1 +
1𝑟(1 + 𝑝𝐴)
1 +1𝑟−2𝑟𝑝𝐴
DESIGN STEP-GROWTH PRECURSOR TOWARD HIGH MOLAR MASSES
Incorporation of AA homopolymer
after depletion of BB
Longer AA homopolymer chains if excess of AA
Stage 1
Stage 2
r >> 1BBAA
r = 1BBAA
DESIGN STEP-GROWTH PRECURSOR TOWARD HIGH MOLAR MASSES
DESIGN STEP-GROWTH PRECURSOR TOWARD HIGH MOLAR MASSES
OUTLINELight-induced step-growth polymerization
Experimental observations
Theoretical framework
Rate coefficients in view of design
Design step-growth precursor toward high molar masses
Chain extension by RAFT polymerization
Experimental observations
Theoretical framework
Rate coefficients in view of design
Design toward microstructural control
Conclusions
EXPERIMENTAL OBSERVATIONS
Segmented copolymer
• solubility
• still copolymer
• time for pA
Precursor copolymer
6 h
Bivariate
(1) chain length
(2) # RAFT moieties
THEORETICAL FRAMEWORK
12 dormant chain types, 7 radical types, > 200 reactions
Step-growth polymer precursor for r = 𝑁𝐴,0
𝑁𝐵,0= 1.5
[Styrene]0=8.74 mol L-1
[AIBN]0=4.85 10-3 mol L-1
Step-growth polymer precursor for r = 𝑁𝐴,0
𝑁𝐵,0= 1
[Styrene]0=8.74 mol L-1
[AIBN]0=4.85 10-3 mol L-1
RATE COEFFICIENTS IN VIEW OF DESIGN
Step-growth precursor Xstyrene = 1 %
Xstyrene = 6 %Xstyrene = 3 % Incorporation of styrene
RAFT groups well-located
Chain extension ~ # RAFT
r = 𝑁𝐴,0
𝑁𝐵,0= 1.5
DESIGN TOWARD MICROSTRUCTURAL CONTROL
Multisegment copolymers with on average 70 monomer units per segment
OUTLINELight-induced step-growth polymerization
Experimental observations
Theoretical framework
Rate coefficients in view of design
Design step-growth precursor toward high molar masses
Chain extension by RAFT polymerization
Experimental observations
Theoretical framework
Rate coefficients in view of design
Design toward microstructural control
Conclusions
CONCLUSIONS
Step-growth polymerization of benzaldehyde and fumarate monomers containing
a trithiocarbonate RAFT moiety employing light-induced Diels Alder chemistry is
introduced.
Unconventional off-stochiometric conditions necessary to compensate for the
unavoidable homopolymerization of the benzaldehyde monomer.
The step-growth precursor polymer is successfully employed as a multifunctional
CTA for RAFT polymerization, leading to a well-defined segmented copolymer.
Polymer synthesis and advanced kinetic modeling strategies are combined to
identify optimal synthetic conditions and to predict their structural composition.
ACKNOWLEDGMENTS
Fund for Scientific Research Flanders (FWO; 1S37517N)
Karlsruhe Institute of Technology, KIT, Germany: STN and BIFTM
Queensland University of Technology, Australia
Australian Research Council
Baden-Wuerttemberg Stiftung
Elite Network Bavaria
LABORATORY FOR CHEMICAL TECHNOLOGY
Technologiepark 914, 9052 Ghent, Belgium
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https://www.lct.ugent.be