Unravelling Polymerization Kinetics via Precision Size Exclusion Chromatography

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1 Unravelling Polymerization Kinetics via Precision Size Exclusion Chromatography Dr. Alexander P. Hähnel Institute for Chemical Technology and Polymer Chemistry KIT University of the State of Baden-Württemberg and National Large-scale Research Center of the Helmholtz Association

2 What Are We Doing? determination of absolute MWDs (molecular weight distribution) via universal calibration employing MHKS parameters (Mark-Houwink-Kuhn-Sakurada) via on-line light scattering of each individual sample (MALLS multi angle laser light scattering) 2 of Alexander P. Hähnel

industry (heat transfer, stirring, process duration, ) kinetic modeling of entire polymerization

3 And Why? to obtain kinetic information about the polymerization necessary for: the planning of reactor tanks in industry (heat transfer, stirring, process duration, ) kinetic modeling of entire polymerization processes (MWD, Ð, degree of functionalization, copolymer composition, ) choosing appropriate controlling agents in RDRP techniques, such as RAFT and NMP k p R i + M R i +1 3 of Alexander P. Hähnel

4 Outline Introduction Polymer Synthesis via Pulsed Laser Polymerization Absolute MWDs via MHKS initiator monomer (solution) growing chain terminated chain Absolute MWDs via MALLS 4 of Alexander P. Hähnel

5 Synthesis of Polymer PLP Pulsed Laser Polymerization laser pulse generates radicals, which start to propagate consecutive laser pulse leads to mass extinction of radicals initiator monomer (solution) growing chain terminated chain some remaining radicals of both generations propagate further terminated polymer chains accumulate, which have propagated for one or two (or more) dark times 5 of Alexander P. Hähnel

Synthesis of Polymer PLP Pulsed Laser Polymerization PLP produces a large, a smaller, and even smaller populations of polymer chains, which have

6 Synthesis of Polymer PLP Pulsed Laser Polymerization PLP produces a large, a smaller, and even smaller populations of polymer chains, which have propagated for one, two, or more dark time(s), respectively. initiator monomer (solution) growing chain terminated chain 6 of Alexander P. Hähnel

7 Molecular Weight Distribution aim: determination of the absolute molecular weight of polymer chains, which have grown for one (two or more) dark time(s) MW of the inflection point(s) is determined M 1 M 2 M 3 7 of Alexander P. Hähnel

Kinetic Evaluation aim: determination of the absolute molecular weight of polymer chains, which have grown for one (two or more) dark time(s) MW of the inflection point(s) is determined k p can be

8 Kinetic Evaluation aim: determination of the absolute molecular weight of polymer chains, which have grown for one (two or more) dark time(s) MW of the inflection point(s) is determined k p can be deduced from the MWs global trends family type behavior intuition for new monomers Arrhenius Plot A, E a Haehnel, A. P.; Schneider-Baumann, M.; Arens, L.; Misske, A. M.; Fleischhaker, F.; Barner-Kowollik, C. Macromolecules 2014, 47, of Alexander P. Hähnel

9 Absolute Molecular Weights key information: absolute MW of the inflection points accessible via MALLS analysis of each individual sample or the correct, polymer specific MHKS parameters 9 of Alexander P. Hähnel

10 Outline Introduction Polymer Synthesis via Pulsed Laser Polymerization Absolute MWDs via MHKS Absolute MWDs via MALLS 10 of Alexander P. Hähnel

Universal Calibration MHKS parameters are accessible via triple

] noisy, dependent on integration borders, 1.0 0.8 0.6 0.4 0.

2 AH230a RI Visko MALLS Polymer Handbook 0.0 0.

11 Universal Calibration MHKS parameters are accessible via triple detection SEC (viscosimetry and MALLS) normalized intensity [a.u.] noisy, dependent on integration borders, AH249a RI Visko MALLS normalized intensity [a.u.] AH230a RI Visko MALLS Polymer Handbook retention time [min] retention time [min] 11 of Alexander P. Hähnel

12 Universal Calibration MHKS parameters are accessible via triple detection SEC (viscosimetry and MALLS) of narrowly distributed polymer samples covering a broad molecular weight range How can we obtain such samples? Haehnel, A. P.; Schneider-Baumann, M.; Hiltebrandt, K. U.; Misske, A. M.; Barner-Kowollik, C. Macromolecules 2012, 46, of Alexander P. Hähnel

$fractionation of broadly$ $fractions 13 of 24 1.10.$

13 MHKS Parameter Determination via fractionation of broadly distributed polymers via SEC columns ~ 20 fractions 13 of Alexander P. Hähnel

14 MHKS Parameter Determination construction of MHKS plots universally applicable MHKS parameters for the given system (polymer, analysis temperature & solvent, degree of branching, ) α 14 of Alexander P. Hähnel

15 Effect of MHKS parameters Post analysis re-calibration is possible 1+ α 1 K log M = log M + log α2 1+ α2 K 2 SEC AH Hz 800 pulses 50.0 C [a.u.] M n [g mol -1 ] Lit. MHKS of SMA preliminary new MHKS α vs K [10-5 dl g -1 ] Haehnel, A. P.; Schneider-Baumann, M.; Hiltebrandt, K. U.; Misske, A. M.; Barner-Kowollik, C. Macromolecules 2012, 46, of Alexander P. Hähnel

16 Effect of MHKS parameters α = 0.76 instead of was employed (K stays the same) changes in MW at the POI: 16 kg/mol 21 kg/mol T [ C] kg/mol 36 kg/mol BeA 1 M in toluene A = L mol -1 s E a = kj mol -1 ln (k p / [L mol -1 s -1 ] ) BeA 1 M in toluene A = L mol -1 s E a = kj mol T -1 [K -1 ] Haehnel, A. P.; Wenn, B.; Kockler, K.; Bantle, T.; Misske, A. M.; Fleischhaker, F.; Junkers, T.; Barner-Kowollik, C. Macromol. Rapid Commun., submitted. 16 of Alexander P. Hähnel

17 Requirements and Limitations Method is: straightforward yet time consuming due to evaporation of solvent and applicable to THF soluble monomer/polymer systems without aging and time/storage stable during evaporation of THF major problems with amine containing monomer systems 17 of Alexander P. Hähnel

18 Outline Introduction Polymer Synthesis via Pulsed Laser Polymerization Absolute MWDs via MHKS Absolute MWDs via MALLS 18 of Alexander P. Hähnel

19 Absolute MWDs via MALLS Method is: elaborate evaluation of each individual sample and applicable to monomer/polymer systems soluble e.g. in DMAc THF soluble systems, which suffer from aging, which are not time/storage stable O O O N NH O O O O NH 2 O O N O O N O ureidoethyl methacrylate UMA hydroxy - iso - propylcarbamate acrylate HPCA N, N - dimethylaminoethyl methacrylate DMAEMA morpholinyl ethyl methacrylate MOMA O O O N Haehnel, A. P.; Stach, M.; Chovancova, A.; Rueb, J. M.; Delaittre, G.; Misske, A. M.; Lacik, I.; Barner-Kowollik, C. Polym. Chem. 2014, 5, (2 - Dimethylaminoethyloxy) e thyl methacrylate LupN107 - MA 19 of Alexander P. Hähnel

20 Absolute MWDs via MALLS O O O N NH ureidoethyl methacrylate UMA O O O O NH 2 hydroxy - iso - propylcarbamate acrylate HPCA 20 of Alexander P. Hähnel

21 Absolute MWDs via MALLS challenge: reproducibility among several analysis runs, samples, and polymers synthesized under similar conditions normalized intensity [a.u.] C15MA sample a sample b RI MALLS retention time [min] 21 of Alexander P. Hähnel

22 Absolute MWDs via MALLS challenge: reproducibility among several analysis runs, samples, and polymers synthesized under similar conditions among different measurement days ln (k p / [L mol -1 s -1 ] ) of Alexander P. Hähnel DMAEMA bulk absolute MW via triple SEC linear fit A = A and E a not 6 L mol determinable -1 s -1 E a = kj kj mol -1 day 1 T [ C] day T -1 [K -1 ]

23 Summary Determination of MHKS parameters via triple detection SEC is favorable universally applicable (standard SEC-RI) allows straightforward and reproducible evaluation of MWDs enables fast processing of kinetic data limited to THF soluble, time stable system Evaluation via MALLS elaborate, especially reproducibility high system tolerance (DMAc soluble or non-time stable ) 23 of Alexander P. Hähnel

24 ACKNOWLEDGEMENT Thanks to Christopher Barner-Kowollik and BASF, especially Andrea Misske and Friederike Fleischhaker Maria Schneider, Katrin Kockler, macorarc team (KIT) Christoph Weder, Yoan C. Simon (AMI, Uni Fribourg, Suisse) 24 of Alexander P. Hähnel

25 References 25 of Alexander P. Hähnel

26 re-calibration with new MHKS parameters SEC AH Hz 800 pulses 50.0 C [a.u.] The molecular weights of the inflection points obtained with a set of MHKS parameters via SEC can be transformed into the correct molecular weights for another set of MHKS parameters. 1+ α1 1 K 1 log M2 = log M1+ log 1+ α 1+ α K M n [g mol -1 ] 1.2x x x Derivative SEC AH Hz 800 pulses 50.0 C [a.u.] Since -4.0x10 there is no significant difference M n [g mol -1 ] molecular weight Lit. MHKS of SMA preliminary own MHKS α vs K dl g re-calibration can be preferred to re-execution! literature MHKS own MHKS re-calibrated SEC AH Hz 800 pulses 50.0 C [a.u.] own MHKS re-executed k p1 /k p2 L L L recalibration of the whole elution chromatogram with own MHKS parameters 1.2x x x x10-5 Derivative SEC AH Hz 800 pulses 50.0 C [a.u.] 26 of Alexander P. Hähnel

27 determination of MHKS parameters How the triple detector SEC chromatograms should look like normalized intensity [a.u.] PS standard g/mol LS Visko RI retention time [min] Fractionation is necessary! Reality of broad distributed polymers synthesized via PLP: - bad signal to noise ratio - broad distributed polymer affects the determination of M w and η - low molecular impurities (monomer, BHT, ) additionally affect the concentration - minor changes in the integration borders result in major changes in M w and η - no high η values can be achieved normalized intensity [a.u.] AH249a LS Visko RI normalized intensity [a.u.] AH230a LS Visko RI normalized intensity [a.u.] AH250a LS Visko RI retention time [min] retention time [min] retention time [min] 27 of Alexander P. Hähnel

28 determination of MHKS parameters How the triple detector SEC chromatograms should look like normalized intensity [a.u.] PS standard g/mol RI Visko LS retention time [min] Valid MHKS-parameters are obtained from the resulting η-m w plot after fractionation η [ml g -1 ] SMA after fractionation linear fit K = dl/g = cm 3 /g α = M w [g mol -1 ] Literature: K = dl/g = cm 3 /g α = 0.67 normalized intensity [a.u.] psma fraction 8a RI Visco LS PDI = 1.12 M w = g mol -1 η = normalized intensity [a.u.] psma fraction 7a RI Visco LS PDI = 1.10 M w = g mol -1 η = MHKS parameters α = K = dl g retention time [min] retention time [min] 28 of Alexander P. Hähnel

29 References Publications contributing to the current thesis 1. Global Trends for k p? The Influence of Ester Side Chain Topography in Alkyl (Meth)Acrylates Completing the Picture Haehnel, A. P.; Schneider-Baumann, M.; Arens, L.; Misske, A. M.; Fleischhaker F.; Barner-Kowollik, C. Macromolecules 2014, 47, (Meth)Acrylic Monomers with Heteroatom-Containing Ester Side Chains: A Systematic PLP-SEC and Polymerization Study Haehnel, A. P.; Stach, M.; Chovancová, A.; Rueb, J. M.; Delaittre, G.; Misske, A. M.; Lacík, I.; Barner-Kowollik, C. Polymer Chemistry 2014, 5, Global Trends for k p? Expanding the Frontier of Ester Side Chain Topography in Acrylates and Methacrylates Haehnel, A. P.; Schneider-Baumann, M.; Hiltebrandt, K. U.; Misske, A. M.; Barner-Kowollik, C. Macromolecules 2013, 46, Publications arising from further activities 4. Glass Transition-, Melting- and Decomposition Temperatures of Tailored Polyacrylates and Polymethacrylates: General Trends and Structure-Property Relationships Fleischhaker F.; Haehnel, A. P.; Misske, A. M.; Blanchot, M.; Haremza, S.; Barner-Kowollik, C. Macromolecular Chemistry and Physics 2014, 215, Investigating Cu(0) Mediated Polymerizations: New Kinetic Insights Based on a Comparison of Kinetic Modeling with Experimental Data Haehnel, A. P.; Fleischmann, S.; Hesse, P.; Hungenberg, K.-D.; Barner-Kowollik, C. Macromolecular Reaction Engineering 2013, 7, Highlighted in the promotion flyer Macromolecular Journals and granted with open access. 6. Cyclic and polycyclic tellurium tin and tellurium lead compounds synthesis, structures and thermal decomposition Traut, S.; von Hänisch, C.; Hähnel, A. P.; Stahl, S. Chemical Communications 2012, 48, Dichloro organosilicon bismuthanes as precursors for rare compounds with a bismuth pnictogen or bismuth tellurium bond Traut, S.; Hähnel, A. P.; von Hänisch, C. Dalton Transactions 2011, 40, of Alexander P. Hähnel

30 Free Radical Polymerization Mechanism 30 of Alexander P. Hähnel

accurate and robust determination of propagation

31 The PLP-SEC Method Pulsed Laser Polymerization Size Exclusion Chromatography recommended by the IUPAC accurate and robust determination of propagation rate coefficients 31 of Alexander P. Hähnel

32 Acrylates Complex Polymerization Mechanism 32 of Alexander P. Hähnel

33 Summary of the PLP-SEC Method PLP experiment Temperature T [ C] Frequency f [Hz] Pulse repetition n -- Energy per pulse E [mj] Initiator concentration c ini [mol L -1 ] c radical SEC measurement elution chromatogram calibration with MHKS parameters calculation ~ 100 experiments check of the consistency criteria selection of valid samples density of the reaction mixture smoothing, differentiation, determination of the maxima in the derivative Arrhenius parameters A, E a Arrhenius plot linear fit 33 of Alexander P. Hähnel

Arrhenius Parameters Acrylates low activation energies E a = 12-19

6-10 7 L mol-1 s-1 O Methacrylates high activation energies E a =

A = 10 6-10 7 L mol-1 s-1 structure-property relationships desired

34 Arrhenius Parameters Acrylates low activation energies E a = kj mol -1 error range ±2 kj mol -1 high frequency factor A = L mol-1 s-1 O Methacrylates high activation energies E a = kj mol -1 error range ±1 kj mol -1 O R high frequency factor A = L mol-1 s-1 structure-property relationships desired not readily detectable among A and E a 34 of Alexander P. Hähnel

35 Outline Introduction PLP-SEC Method Basic Operating Principle Main Goal Details of the PLP-SEC Method Global Trends for Branched Alkyl Methacrylates Linear Alkyl Methacrylates and Acrylates Branched Alkyl Acrylates? Heteroatom Containing (Meth)Acrylates Application in Reversible Deactivation Radical Polymerization Techniques 35 of Alexander P. Hähnel

* isomeric mixture derived via oligomerization of butene (or propene) with subsequent

36 Series of Alkyl Methacrylates Haehnel, A. P.; Schneider-Baumann, M.; Hiltebrandt, K. U.; Misske, A. M.; Barner-Kowollik, C. Macromolecules 2012, 46, * isomeric mixture derived via oligomerization of butene (or propene) with subsequent hydroformylation and reduction to the alcohol which is esterified 36 of Alexander P. Hähnel

37 Branched Alkyl Methacrylates family type behavior due to strong steric interactions independent of the specific structure of the ester side chain 37 of Alexander P. Hähnel

38 Branched Alkyl Methacrylates family type behavior 38 of Alexander P. Hähnel

39 Series of Alkyl (Meth)Acrylates Haehnel, A. P.; Schneider-Baumann, M.; Hiltebrandt, K. U.; Misske, A. M.; Barner-Kowollik, C. Macromolecules 2012, 46, Haehnel, A. P.; Schneider-Baumann, M.; Arens, L.; Misske, A. M.; Fleischhaker, F.; Barner-Kowollik, C. Macromolecules 2014, 47, of Alexander P. Hähnel

40 Linear Alkyl Methacrylates steady increase of k p with increasing ester side chain length 40 of Alexander P. Hähnel

41 Linear Alkyl Acrylates steady increase of k p with increasing ester side chain length 41 of Alexander P. Hähnel

Linear Alkyl (Meth)Acrylates steady increase of k p with increasing ester side chain length decreasing concentration of polar ester moieties leads to a decreasing stabilization of the

42 Linear Alkyl (Meth)Acrylates steady increase of k p with increasing ester side chain length decreasing concentration of polar ester moieties leads to a decreasing stabilization of the attacking radical in the transition state 42 of Alexander P. Hähnel Junkers, T.; et al. Macromolecules 2010, 43, Barner-Kowollik, C.; et al. Polym. Chem. 2014, 5,

43 Series of Alkyl Acrylates Haehnel, A. P.; Schneider-Baumann, M.; Arens, L.; Misske, A. M.; Fleischhaker, F.; Barner-Kowollik, C. Macromolecules 2014, 47, * isomeric mixture derived via oligomerization of butene (or propene) with subsequent hydroformylation and reduction to the alcohol which is esterified 43 of Alexander P. Hähnel

the propagation reaction no steric interactions with

44 Branched Alkyl Acrylates no family type behavior the specific structure of the ester side chain affects the propagation reaction no steric interactions with an α-methyl group 44 of Alexander P. Hähnel

45 Branched Alkyl Acrylates no family type behavior the specific structure of the ester side chain affects the propagation reaction no steric interactions with an α-methyl group 45 of Alexander P. Hähnel

influenced by specific structure within the described families Branched Alkyl

46 Conclusion Linear Alkyl (Meth)Acrylates k p increases steadily with increasing number of C-atoms Branched and Cyclic Alkyl Methacrylates k p is not decisively influenced by specific structure within the described families Branched Alkyl Acrylates no family type behavior no clear trend 46 of Alexander P. Hähnel

47 Fundamental Kinetics d[r ] dt = 2 f k d [I] d[m] dt = k i i p [R i ][M] d [R ] i, j = 2 kt i j dt [R i ][R j ] steady state approximation for intermediate radicals d [R dt 47 of Alexander P. Hähnel ]! 2 = 0 = 2 f kd[i] 2 kt[r ] ] = [R f k d [I] k t 0.5

48 Fundamental Kinetics d[m] dt = k i i p [R i ][M] d[m] dt ] = [R f k d [I] k t f k i = rp = kp [I] kt [M] k [R][M] p ν = = 2 kt k [M] p 2 [R] 2 k [R] termination defined via PLP t 48 of Alexander P. Hähnel

49 Fundamental Kinetics M i ν k [R][M] p = = = 2 kt = ik [M] t p 0 k [M] 2 [R] 2 k [R] p t termination defined via PLP kinetic chain length depends on laser repetition frequency 49 of Alexander P. Hähnel

50 Summary of the PLP-SEC Method selection of valid samples according to consistency criteria reproducibility low conversion (constant [M]) higher inflection points observable 0.9 < k p1 /k p2 < 1.1 influencing by variation of: frequency temperature independent from: photoinitiator concentration laser pulse energy laser pulse repetition number 50 of Alexander P. Hähnel

Hetero Atom Containing (Meth)Acrylates 51 of 24 1.10.2014 Alexander P. Hähnel Haehnel, A. P.; Stach, M.; Chovancova, A.; Rueb, J. M.; Delaittre, G.; Misske, A. M.; Lacik, I.

51 Hetero Atom Containing (Meth)Acrylates 51 of Alexander P. Hähnel Haehnel, A. P.; Stach, M.; Chovancova, A.; Rueb, J. M.; Delaittre, G.; Misske, A. M.; Lacik, I.; Barner-Kowollik, C. Polym. Chem. 2014, 5, Barner-Kowollik, C.; Bennet, F.; Schneider-Baumann, M.; Voll, D.; Rölle, T.; Facke, T.; Weiser, M.-S.; Bruder, F.-K.; Junkers, T. Polym. Chem. 2010, 1,

52 Hetero Atom Containing (Meth)Acrylates increasing k p with increasing ester side chain length 52 of Alexander P. Hähnel

53 Hetero Atom Containing (Meth)Acrylates elevated k p high polarity / hydrogen bonding 53 of Alexander P. Hähnel

Hetero Atom Containing (Meth)Acrylates k p and R p provide access to averaged k t Monomer average k t k 50 C p viscosity L mol 1 s 1 L mol 1 s 1 MA ~10 8 25 600 low DA ~10 6 32 000 high HPCA 2.

54 Hetero Atom Containing (Meth)Acrylates k p and R p provide access to averaged k t Monomer average k t k 50 C p viscosity L mol 1 s 1 L mol 1 s 1 MA ~ low DA ~ high HPCA high MMA ~ low DMA ~ high UMA high on-line NMR at elevated temperatures k t is decreased due to high viscosity analogous to DA 54 of Alexander P. Hähnel

55 Hetero Atom Containing (Meth)Acrylates application in controlled polymerization (RAFT) HPCA / CPDA / AIBN at 60 C in DMSO HPCA MA / DOPAT / AIBN at 60 C in DMAc 55 of Alexander P. Hähnel

56 Hetero Atom Containing (Meth)Acrylates application in controlled polymerization (NMP) UMA / Sty / MAMA-SG1 / SG1 at 90 C in DMAc UMA / Sty / MAMA-SG1 / SG1 at 90 C in DMSO 56 of Alexander P. Hähnel

57 Outlook Investigation of linear acrylates in 1 M solution in toluene as well as in butyl acetate in comparison to bulk: previous reports state a decrease of k p in toluene with increasing ester side chain length currently not observed Investigation of a series of methacrylates containing amine and further functionalities in the ester side chain specific influence of the functional moiety are there similar trends detectable as for alkyl (meth)acrylates? 57 of Alexander P. Hähnel

58 Summary of the PLP-SEC Method PLP experiment SEC measurement Parameters: Temperature T [ C] Frequency f [Hz] Pulse repetition n -- Energy per pulse E [mj] Initiator concentration c ini [mol L -1 ] c radical Elution Chromatogram Calibration with MHKS parameters Calculation Arrhenius plot Smoothing, Differentiation, Determination of the maxima in the derivative Linear fit Check of the consistency criteria selection of valid samples Arrhenius parameters A, E a - reproducibility Density of the - low reaction conversion mixture (constant [M]) - higher inflection points observable < k p1 /k p2 < influencing by variation of: - laser pulse repetition number - frequency - independent from: - photoinitiator concentration - laser pulse energy 58 of Alexander P. Hähnel

59 Branched Alkyl Methacrylates family type behavior T [ C] ln (k p / [L mol -1 s -1 ] ) joint fit A = L mol -1 s -1 E a = kj mol -1 C17MA PHMA EHMA idema TDAMA TDNMA T -1 [K -1 ] 59 of Alexander P. Hähnel

60 Branched Alkyl Acrylates ln (k p / [L mol -1 s -1 ] ) no family type behavior the specific structure of the ester side chain affects the propagation reaction no steric interactions with an α-methyl group T [ C] tba BnA iboa EHA PHA INA-A TDA-A TDN-A C17A C21A a joint Arrhenius fit is not appropriate T -1 [K -1 ] 60 of Alexander P. Hähnel

of Polystyrene 4-arm Stars Synthesized by RAFT- Mediated Miniemulsions.

Supporting Information to Narrow Molecular Weight and Particle Size Distributions of Polystyrene 4-arm Stars Synthesized by RAFT- Mediated Miniemulsions. Hazit A. Zayas, Nghia P. Truong, David Valade,