Barner-Kowollik, Christopher

D'hooge, Dagmar

De Keer, Lies

Gegenhuber, Thomas

Goldmann, Anja

Reyniers, Marie-Françoise

Van Steenberge, Paul

Ghent University Academic Bibliography

CRICOS No. 00213Ja university for the world®realT. Gegenhuber, L. De Keer, A. S. Goldmann, P.H.M. Van Steenberge, M.F. Reyniers, D. R. D´hooge, C. Barner-KowollikSTEP-GROWTH POLYMERS AS MACRO CHAIN TRANSFER AGENTS – AN EXPERIMENTAL AND THEORETICAL STUDY 2 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschThe Road into the Light?And if You feel that You can´t go on, in the Light You will find the Road. (“In the Light“, Physical Graffiti, Led Zeppelin © 1975)Tetrazole toNitrile-imineMethyl-Benzaldehyde to ”Photoenol“Phenacylsulfide toThioaldehydeAzirine toNitrile-ylide3 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschReaction Pathway and Motivation• Incorporation of RAFT group within the backbone of a step-growth polymer4 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschGeneral Polymerization Concept• Step-growth polymerization using a bifunctional ortho-methyl benzaldehyde and a bisfumarate with a trithiocarbonate group• Chain extension by conventional RAFT polymerizationM1 M2 P1P25 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, Stellenbosch2.5 3.0 3.5 4.0 4.5  Intensity/ a.u.log(M)SimulationMonomer Stability and Homopolymerization• Irradiation with conditions for step-growth polymerization of M1 and M2• Determination of ksideRAFT-fumarate M1 stable, benzaldehyde M2 reacts with itself2.5 3.0 3.5 4.0 4.5 5.0 5.5 M1 M2 M1 after irradiation M2 after irradiation  Normalized RI Responselog(M)M1M2PS calibration6 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschSide Reactions and kside Determination• Possible side reactions of activated M2 ortho-quinodimethaneand the carbonyl species of the benzaldehyde• Determination of kmain in relation to kside via small moleculesM2 FF-M2-FM2 M27 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, Stellenboschkmain vs. kside and Off-Stoichiometry in Simulations• Side reaction, imbalance and k values• If kside = kmain, still strong suppression of sidereaction• With excess A more sidereaction occuring0 2 4 6 8 100.00.20.40.60.81.0  f AB kside/ kmainr = 11.0 1.2 1.4 1.6 1.8 2.00.20.40.60.81.0 kside < kmain kside = kmain kside > kmain  f AB r𝑟 =𝑁𝐴,0𝑁𝐹,00 800 1600 2400 32000.0000.0050.0100.0150.020  cX / molL-1 Time / min AA AFr = 1 kside = kmain8 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschSmall Molecule Reaction: kmain DeterminationConversion (NMR): 93 %Conversion (NMR): 87 %M2 F2.0 2.5 3.0 3.5 4.0 r = 1 r = 1.43  Normalized RI Responselog(M)2.4 2.8 3.2 3.60.00.20.40.60.81.0F-M2   log(M) r = 1 r = 1.43normalized fmF-M2-Fr = 1 with kside = 0.2 kmain9 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschStep-Growth Polymerization Kinetics with Equimolarity28 30 32 34 36 38 45 min 1 h 4 h 8 h t0 10 min 20 min 30 min  Retention time / minNormalized RI Responser = 1 and kside = 0.2 kmain0 20 40 60 80 100010203040 Experimental Simulation  XwConversion / %10 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, Stellenbosch10 15 20 25 30  r = 0.99 r = 1.05 r = 1.20 r = 1.30 r = 1.50 r = 1.75 r = 2.00   Normalized RI ResponseRetention time / minStep-Growth with Imbalance using the Side Reaction• Increasing the amount of M2 (photoenol)• Highest Mw for the 1/1.75 ratio of M1/M2 (excess photoenol)• At ½ ratio decrease of the Mw1.00 1.25 1.50 1.75 2.001020304050607080  Mw (exp.) trendline  Mw / kgmol-1r𝑟 =𝑁𝑀2𝑁𝑀1M1 M211 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschStep-Growth Polymerization with Off-Stoichiometry• Excess of M2 (also increased concentration, c(M1) = const.)• High molecular weight species formed due to coupling offurther M2-M212 16 20 24 28 32 M1 M2 t0 10 min 20 min 30 min 45 min 60 min 90 min  2 h 4 h 6 h  Normalized RI ResponseRetention time / min20 40 60 80 100075150225300375  Experimental Simulation  Xw Conversion / %0 20 40 60 80 1000.000.010.020.030.040.050.060.070.08 r = 1 r = 1.75  mass fraction M2 homopolymerConversion / %M1 M212 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschMechanistic Considerations• Insertion of M2M2 homopolymer in M2M1M2M1 (M2+M1) copolymer after exhaustion of M2• Formation of high molecular species according to CarotherCopolymerHomopolymerM2 M113 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschChain Extension by RAFT Polymerization• Conventional RAFT polymerization using step-growth polymer with ratio of 1/1.5 M1/M2 (1/1.75 polymer with solubility issues)2 3 4 5 6 Step-growth 0.25 h 0.5 h 1 h 1.5 h 2 h 3 h 4 h  Normalized Intensitylog(M)1.0 1.5 2.0 2.5 3.0 3.5 4.0102030405060  Mn / kgmol-1Conversion / %14 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschMechanistic Considerations• Symmetric trithiocarbonate fragmentation in a random fashion– Up to 200 different reactions theoretical taken in account– Statistical balancing of chain length by mixing long and short chainsduring the addition and fragmentation-15 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschSummary• Step-growth polymerization by light-induced reactions Use of ortho-quinodimethanes and fumarates Side reaction and theoretical description of kside/kmain Off-stoichiometry to obtain high molecular species• Chain extension by RAFT polymerization Controlled reactio Calculations and simulations currently under investigation High molecular species obtained16 13th April 2017 UNESCO IUPAC Conference on Macromolecules & Materials 2017, StellenboschAcknowledgements – Barner-Kowollik TeamFollow Macroarc @BarnerKowollikProf. Dagmar D´hooge andcolleagues

Step-growth polymers as macro chain transfer agents - an experimental and theoretical study

https://biblio.ugent.be/publication/8537403/file/8537408

Step-growth polymers as macro chain transfer agents - an experimental and theoretical study

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