RAFT-Polymerization of N-Vinyl Pyrrolidone and MethylMethacrylate for Synthesis of Functional Co-BlockpolymerBinders for Solid Electrolyte Batteries.

Author: Anders Ostman Supervisor: Tim BowdenExamination project at the Department of Polymer Chemistry, Angstromslaboratioriet,

Uppsala University (UU), Uppsala, Sweden.

Abstract: This report is a summary of laboratory work done in a research groupfrom the department of polymer chemistry of Uppsala University. The project work wasto synthesize functional polymers through [RAFT]-polymerization, based off of N-VinylPyrrolidone [NVP] and continue the ”living” polymerization with Methyl Methacrylate[MMA] to create an ion conducting binder to serve in an solid electrolyte battery. With[AIBN] being the radical initiator, that was used in an oxygen free matrix and system,to polymerize the monomer. A reaction of [40:1:0.2] molar equivalents of [NVP]:[RAFT-reagent]:AIBN was the mixture that seemed to be the one combination that worked, thusbeing the product that the rest of the project was expanded upon. 1g of [NVP] and 50mgof RAFT was added together. After three freeze thaw cycles the 7.8mg of AIBN wasadded. After RAFT-polymerization aminolysis was performed. The polymerized product,with about 6.5 repeating units, had 0.295g of tri-phenyl phosphine added to it. After threefreeze thaw cycles argon and 0.27mL of ethanol-amine, the base, was pipetted into the glass,and finally ”Michael Click Addition” to make the desired product. A volume of 0.3137mLof the Michael Click reagent was pipetted into the aminolysis product along with saturatedHNaCO3 water solution. However, due to the monomer’s diverse functionality, sensitivityto impurities and instability, also because of synthesized by products, many problemsoccurred as the synthesis progressed in time. The desired product was not synthesized andfurther studies has to be made.

Introduction

Batteries are today extremely common. Inour machines, cars and in general small ev-eryday apparatuses. Most of these batterycells contain some sort of ion conductingmedium or mass. This medium is most com-monly made out of a liquid, e.g battery acidH2SO4. When batteries grow old these typesof chemicals can be difficult to get rid of,or just leak straight into the environment,which could cause long term damage on our

biosphere. One way of erasing this issuewould be to exchange the ion conductingmedium, the electrolyte, from a liquid tosomething which could be considered a solidto a solid electrolyte battery. [5]

The ambition behind this project was totest one specific polymeric compound basedoff of two different monomers, which wouldbe the electrolyte binder later mixed with alithium salt. One monomer possessing theion carrying properties and one monomerwhich would give it more mechanical prop-

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erties in terms of rigidity and solidity. Ifthe ambition is executable it could also bepossible to give the battery consisting of asolid electrolyte any imaginable form. Oneexample of this would be to remove a vehi-cle battery and then turn the entire carriagebody into a solid electrolyte battery instead.

N

CH3

S N

S

Figure 1: Structure of used RAFT reagent

RAFT (Reversible addition-fragmentationchain-transfer) polymerization is a techniqueused for polymerizing e.g vinyl compoundswith good control of the chain lengths dur-ing the synthesis. It is referred to as a”living” polymerization due to its’ inabil-ity to terminate mid-synthesis. It is alsocommonly used for homo-polymer synthe-sis that perhaps might be the only wayto polymerize a certain chemical, such as[NVP], due to its’ other functional groups.[6][3] The RAFT chemical, in this particularcase S-Cyanomethyl-N-methyl-N-(pyridin-4-yl)dithiocarbamate (C10H10N2S2), see Fig-ure 1.

The double bond to the sulphur atomwill break as the first radical monomer at-tacks and form a radical intermediate whichmakes the RAFT chemical very inclined toreact with the monomer, then the it formsa new double bond on the second sulphuratom plus a monomer radical. As a new rad-ically charged molecule springs to life it willreact with the RAFT chemical once again

and the sulphur double bond will switchback. Like a pendulum this continues on andon until the reaction is terminated. [6] SeeFigure 5 in Appendix.

Because of this the average chain lengthsin the mixture will become very similar, giv-ing a low PDI (Poly-Dispersity Index). Alow PDI value will be important as the prop-erties of each polymer might differentiate interms of ion conducting properties or me-chanical properties. If the chains have avery diverse length it will be difficult to de-termine if the chain length is a factor inthe conductive capability, or strength, thepolymer would have. Also, if a low PDIis achievable it makes it easier to changeif another specified length is desired. Thismethod is applied to chemicals such as theN-Vinyl Pyrrolidone [NVP] and the MethylMethacrylate [MMA] in order to create ablock polymer, A-B block based, with func-tional ligands to carry ions through thesystem, acting as a functional binder forthe battery cell. This was accomplishedby using controlled radical polymerizationthrough RAFT polymerization with [NVP]and [AIBN](Azobisisobutyronitrile) as theradical initiating chemical, making thatinto pNVP (poly-NVP), further commenc-ing aminolysis on the pNVP with Ethanol-amine, and then using a dihalogenated com-pound to ”Click” (1:1 ratio between reagentswith no by-products) them together with areaction step called ”Michael Click Addi-tion”, or in this case ”Thiol Michael ClickAddition”. It is insensitive to oxygen andair which makes water a good solvent in thisstep as the monomer makes the whole poly-mer soluble in water. [7] The reagent, seeFigure 2, is 4-bromo-2-(2-(buta-1,3-dien-2-yloxy)ethoxy)-4-methylpent-1-ene dihydrate

2

(C10H15O4Br. Lastly, pMMA is to be syn-thesized upon the halogenated edge of theMC-reagent of the chain to create the B-block in the A-B structure through ATRP(Atom Transfer Radical-Polymerization).

OO Br

OO

Figure 2: Structure of used Michel Clickreagent

The final product shown in the figure, seeFigure 3, displays the structure of the com-pound which would be the end goal of theentire synthesis and project.

n m

A

B

Figure 3: The wanted product showing theA- and B-block polymeric structure

Methods

Many of the terms used in this report, com-mon terminology associated with polymer

chemistry, need an introduction as well. DP,or ”Degree of Polymerization”, is a term thatdescribes the amount of repeating units ofmonomer within the propagated chain. [2]

DP=Mn

M0

Mn is the number average molecularweight and M0 is the molecular weight ofthe given polymer.

Nuclear Magnetic Resonance (NMR)

This technique is very established in labo-ratories which handle organic molecules ofsome sort. The machine uses a very strongmagnetic field to detect atoms such as car-bon or hydrogen which makes it possible toidentify the injected sample. When the mag-netic field turns on the atoms, e.g hydrogen,will all be pulled in the same direction andthen released again to point in the direc-tion it had prior to the field actuation pointthat time. ”Like tiny compass needles” [4]they go from pointing south to then all ofthem pointing north. For hydrogen thereare only two energy states, a high one and alow one; it can either align in the magneticfield (lower) or against it (higher). Depend-ing on how magnetized the proton would beis determined by its’ surrounding atoms andhow it bonds with them. The machine calcu-lates the level differences of nuclei and fromthat a proton NMR spectra can be drawn.[4] The Y-axis conveys the intensity of saidproton shifts and the X-axis shows the ppm(parts per million). Peaks below 4ppm canbe considered to be protons which are rela-tively saturated and above 4ppm the protonscan be considered to be unsaturated. [4]

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Experimental

The aminolysis was preformed to preservethe functionality of the sulphur as a thiolin order to make the reaction with theMichael-Click reagent. The sulphur fromthe thiol and the double bond of the MC-reagent would then react instantly with noby-products into a water soluble compound.

All reactions were followed with protonNMR samples in order to characterize andmake sure that the right characteristics werepresent at all times to make the correct prod-uct. The solvent used for all samples wasCDCl3. Important to note is that when thebaseline fluctuates a lot around all the ”un-saturated” peaks around and below 4 ppmit is a strong indicator of having polymericcharacter in the analysed mixture.

Recrystallization of [AIBN](Azobisisobutyronitrile)

To start off the project a new batch of freshand recrystallized [AIBN] was required in or-der to reduce the risk of having impuritiescorrupting the polymerization. A saturatedmethanol solution of [AIBN](raw) and wasstirred with a magnet stirrer in an E-flaskfor about 20 minutes after the solution couldnot dissolve any more of the [AIBN]. The so-lution was poured through a filter to removethe excess raw, non-recrystallized [AIBN]. Asmall vial filled with the recrystallized prod-uct stood in the a fridge to slowly create newcrystals, and the crystals were then filteredoff again, put in a vial and placed inside avacuum oven to get rid of all the methanolsolvent.

Synthesis of pNVP

Step 1: The initial monomer (NVP), seeFigure 4, was first distilled from a largeround flat bottom flask (250mL), to get ridof the NaOH inhibitor from the reagent, twotimes, with hydroquinone(C6H6O2) addedto stabilize the monomer as it easily creat-ing dimers at higher temperatures, to ensurethat it was clean. Purity was investigatedwith NMR. Due to the instability of the pu-rified reagent it was put in a freezer duringtimes of no usage and defrosted every timebefore usage. Also the RAFT reagent and[AIBN] was kept in either a freezer and/or afridge to reduce decay or degradation.

N O N ORAFTn

Figure 4: Structure of N-Vinyl-Pyrrolidone[NVP] into [pNVP]

Step 2: First off was a concept re-action of a polymer with low molecularweight. The goal was to have an averageMW 10 000 g mol−1 (or a DP (degree of poly-merization) of about 100 repeating units. Toachieve this the molar equivalents were cal-culated. See Table 1. Another synthesiswith different molar equivalents was synthe-sized as well. See Table 2. The reaction witha higher molar equivalence of (NVP) stoodover night to let the polymerization go toabout 60-70% in order to achieve a MW be-tween 60 000 and 70 000 g mol−1.

A magnet stirrer and RAFT-agent wasadded to a nitrogen flask. In order to be able

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to calculate conversion with NMR two dropsof 1-propanol as an internal standard to de-termine the percentage of conversion. Nosolvent was used as the reaction was made asa bulk reaction. Freeze thaw cycles were car-ried out to remove the oxygen from the sys-tem’s matrix, which otherwise would termi-nate the reaction from the start. Argon wasinjected to serve as a coating when the stop-per was pulled off, to protect the mixturefrom air, as the AIBN initiator was added.The argon and the air that might have runinside the nitrogen flask was removed withvacuum and new argon was injected to pre-serve the inert properties.

Step 3: The nitrogen flask containing theNVP-mixture was set in an oil bath with aset temperature of 60 ◦C. The rate of con-version could be determined through takingproton NMR samples with a syringe throughthe rubber stopper seal without introducingair to the system.

Step 4: To terminate the reaction DCMwas added to dissolve and quench the reac-tion. Further the synthesized product wasprecipitated into an e-flask of diethyl ether.The precipitate had a very bright whitecolour and was filtrated through a Buchnerfunnel with a very fine filter paper. Theproduct was set to dry in a vacuum ovenfor at least 10 hours. (Side note: The pNVPwith 40 molar equivalents remained in thenitrogen flask for further synthesis to notlose any product as the amount of reagentsto begin with was initially very small).

Aminolysis of pNVP

After the polymer product (pNVP) had beenwashed and separated, and the average MW

of the polymer as well as number of repeat-

ing units (DP) was calculated, the (pNVP)was added to a new nitrogen flask (though,the exception for the reaction of the mixturewhich was done in the smaller quantity (SeeTable 1 was the only one that was made dueto lack of time)From the estimated averageDP and MW a new table of molar equiv-alents was created in order to prepare theaminolysis. See Table 4. The base used inthe aminolysis and refereed to in Table 4 wasEthanol amine, and the phosphine was tri-phenol phosphine, used as a reducing agentto minimize the chance of creating any S-Sbonds in the mixture as we want to maintainthe functionality of the sulphur as a thiol.

Step 1: First the phosphine was added tothe mixture and dissolved. Freeze thaw cy-cles were preformed to remove the air fromthe system. Argon was injected and the rub-ber septa was removed carefully and the basepipetted down into the mixture. The systemwas put on stirring in room temperature fortwo hours.

Step 2: After stirring for two hours theproduct was precipitated into diethyl ether.The powdered product was then filtratedthrough a Buchner funnel with a filter toseparate the finished product from the un-reacted chemicals still left inside the nitro-gen flask. The clean product was put in aglass flask for storage. The product from[pNVP 40], see Table 1, was weighed to0.214 g which corresponds to 0.001 124 5 molof the MC-reagent.

Michael Click (MC) addition ofpNVP

The ratio between the reacting compoundsin the MC-reaction was 1 to 1, thus the samemolar equivalents were used. The product

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from the aminolysis was added to a glassflask, some water and base (NAHCO3) sat.was added to activate the thiol group anddissolve the polymer. Lastly the MC-reagentwas pipetted into the mixture. It was setto stir for one hour in room temperature.The oily product was dissolved in methanoland rolled in three times with a rotovapour-apparatus. First round bottom flask rolledaway the H2O, and then the two following toremove the methanol left inside the mixture.It was approximated that the density of theMC-reagent was 1.0.

Synthesis of pMMA

The procedure for synthesis of (pMMA) wasapproximately the same as for the (pNVP).A table for the molar equivalents was cre-ated to calculate the correct amounts. SeeTable 6.

Results

Review of Distillation of NVP

The first step of the synthesis was the distil-lation of [NVP]. The boiling point of [NVP]lies between 90−92 ◦C, and it was found thatthe optimal conditions for distillation were92 − 95 ◦C and 8 − 10mbar. As the distilla-tion went on it changed colour. The roundbottom flask, with a flat bottom to increasethe surface area to prevent shock boiling,was initially filled to about 1/3 of the flask.The non-matching boiling points could bebecause of the stabilizing agent in the flask of[NVP] from Sigma Aldrich, which is NaOH.Also, the possibility to create dimers is veryhigh, which further influences the fluctua-tion in the systems boiling point.

The [NVP] with the inhibitor NaOH hada very yellow colour, but as the chemicalwas distilled the colour disappeared and gotcolourless. A proton NMR sample was pre-pared with CDCL3 as solvent. It was foundthat peaks between 5ppm and 6ppm is astrong indicator of the distillate containingdimers, see Figure 6. In general the NMRspectra was bad overall. The fronting ofthe earlier peaks, between 1ppm and 4ppm,could be a sign of polymerization as it hadbeen boiled without an additional stabi-lizer. The product was distilled once againand Hydroquinone to stabilize the system asvinyl compounds often tend to polymerize athigh heat very easily. The proton NMR sam-ple which was taken after showed no signsof anything else but the clean monomer, seeFigure 7. The peaks between 5ppm and6ppm had disappeared completely.

Before distillation had been carried outfiltration was an alternative method to cleanthe monomer from the basic inhibitor butproved to be less effective.

Review of Synthesis of pNVP

During this synthesis there were many triesin order to identify what was wrong initially.The first conclusion that was made was thatthe flask of [NVP], which was opened afew months before this project commenced,probably had gone ”sick” or begun to de-grade. The earliest synthesises of [pNVP]did not work at all. It all remained a yel-low coloured and very watery solution. Theproton NMR samples showed a very strangespectra, which from it was concluded thatmany side reactions had happened.

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Table 1: Molar Equivalents For Synthesis ofpNVP 40

NVP RAFT AIBN

Eqv 40 1 0.2mass 1g 50mg 7.8mgVolume 1mL ∗ ∗

Table 2: Molar Equivalents For Synthesis ofpNVP 450

NVP RAFT AIBN

Eqv 450 1 0.2mass 6.26g 19mg 2.8mgVolume 6mL ∗ ∗

After working past that, purchasing anew [NVP] from Sigma, and doing every-thing thoroughly it was found that after asuccessful synthesis of [pNVP], with 40 mo-lar equivalents see Table 1, with 1-propanolas in internal standard to calculate conver-sion (approx.16%), that the amount of re-peating units only were about 6.5, whichgave an average molecular weight of thepolymer of about 721 g mol−1. This was a lotshorter and lighter polymer than intended,but since it was the first sign of any work-ing synthesis and due to the lack of time itwas decided to continue with the aminolysis.The peak integral of the peak which showsup around 7.02-7.13ppm was compared toeach other before and after synthesis. SeeTable 3. The peak integral of the 1-propanol,0.88ppm, was set to 1, as it would stay thesame through out the synthesis and had avery early peak that does not interfere withany other peaks, which made it easy to iden-tify. See Figure 8 and Figure 9. The very

stretched baseline, seen in Figure 9, is a com-mon indicator of polymeric characteristics inthe sample.

Table 3: Integral Data and Comparison

ppm Ref. Int. Synth.Int. Rat. (%)

7.02-7.13 21.12 17.81 84.3%0.88 1.00 1.00 ∗

The comparison between the integralsof the two separate runs led to a real-isation that approximately 16% of all ofthe monomer in the glass had polymer-ized. Ref.Int. is based off of Figure 8. As”Synth.Int.”, based off of Figure 9, from Ta-ble 3, was a quenched product it was notpossible to put it back for heating and stir-ring as everything had been terminated dueto the introduction of Dichloromethane andoxygen in the system.

Looking at Table 1 it is written thatthere were 40 molar equivalents of [NVP].The DP that was sought after was 100(the average amount of repeating units ina chain), and the molecular weight of [NVP]is 111.14 g mol−1, makes the average molec-ular weight to be 4445.60 g mol−1 from tak-ing 40 · 111.14. As approximately 16% con-version was achieved this gave and averagemolecular weight of 721 g mol−1, the Mn,which would give a DP of simply 6.5 re-peating units when divided by the molecularweight of [NVP], the M0.

Review of Aminolysis of pNVP

The aminolysis was a relatively quick step toperform. Once again as it precipitated intodiethyl ether it took to form of a white andvery light powder. However, there was still

7

some product left at the bottom of the nitro-gen flask, in which the reaction took place,that had a slight yellow tone. It could beby products, though the proton NMR spec-tra was difficult to interpret as the polymericcharacteristics were still present in the spec-tra; so it could not be proven if there wereany trace amounts of relatively saturated byproducts because they could be hidden be-hind the rough base-line. In either case aproduct was made which could be assumedto be the right product based off of the obser-vation of no proven amounts of by products.

Table 4: Molar Equivalents for Aminolysisof pNVP

pNVP Base Phosphine

Eqv 1 20 5mass 0.1568g 0.2748g 0.295gVolume ∗ 0.27mL ∗

Review of Michael Click Additionof pNVP

This step did not go as planned at all. Theidea was that the polymer made was sup-posed to be soluble in water, but in this casethe mixture of the product after aminoly-sis [pNVPam] and water only turned into abeige sludge. It refused to dissolve. Thoughit was given extra time to perhaps dissolvestill it refused to. It could be so that thereactually were quite a high amount of byproduct left from the aminolysis in the fil-tered products. After it was rolled with theroto-vapourizer three times, where two ofthem were with added methanol, the cloudysuspension was still present afterwards. Itbecame a think dark yellow oil. The fact

that there was any sought product insidecould not be proven either. No availabledeuterium-containing solvent that could dis-solve the oily product hindered the study ofthis to the point where it was just assumedto be the wrong product and thrown in thewaste. The proton NMR showed absolutelyno sign of any successful synthesis, probablybecause of the insoluble compounds whichalso were present in the mixture. See Fig-ure 10.

Table 5: Molar Equivalents for ThiolMichael Click Addition of pNVP

pNVPam Michael Click

Eqv 1 1mass 0.214g 0.3137gVolume ∗ 0,3137mL

Review of Synthesis of pMMA

Judging from the result one can absolutelysay that it was successful in regards of cre-ating [pMMA]. Letting it stand over a wholenight, however, was a mistake as it polymer-ized to 99.9%. To make the desired prod-uct the reaction had to be quenched after agiven time to maintain the end group func-tionality, but if the reaction goes to a 100%it terminates and kills all functionality. SeeFigure 5. In this case that happened andcreated a very hard piece of plexiglass. Thiscould not be used in any further experimentsin the project because of that reason.

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Table 6: Molar Equivalents For polymeriza-tion of MMA

pNVP Base Phosphine

Eqv 1 20 5mass 0.1568g 0.2748g 0.295gVolume ∗ 0.27mL ∗

Conclusion

From all of these steps it can be concludedthat most of the lab-work ended in a non-success, mostly because of the lack of time.The envisioned molecule was not made, andthere were many small stops within theproject as the monomer [NVP] was such atroublesome chemical to work with. [3]. Thecited article no [3] brings this problem upas well. Much time which could have beenspent on working was instead placed on try-ing to make the [NVP] work properly, or asintended in the first place. A lot of clean up,trial and error and also queues for machin-ery made the project very time inefficient.Of course, given enough time it would prob-ably have ended with a correct product.

As stated, the monomer [NVP] was dif-ficult to work with, and when it comes tothe monomers purity is extremely importantas trace amounts of anything that containsspecies with good ion carrying properties, orcan make ions easily, will terminate the reac-tions in the glass. The best way to deal withthis was to distil the monomer at least twotimes to remove all the unwanted moleculeswhich, among other effects, cause termina-tion.

When doing this reaction in a bulk, with-out a proper purification step, there seemto be a high risk of leaving in potential by

products during reaction steps. Taking acloser look at the aminolysis it could be de-bated that the reason why the thiol mix-ture was not water soluble completely couldbe because of the lack of purifications steps,such as filtering or precipitation. The reac-tion which got the furthest in this projectwas, though, in fact the vessel containingthe bulk reaction material. The chance ofa ”non-contaminated” product is probablya lot higher if each step is done separatelyand not just added to the same glass likethe most successful reaction was. Doing eachstep separately would be recommended be-cause of this.

Further Studies

Continuation of this project is necessary toreach the desired goal. If the given timeof this project would have been double, to18 weeks instead of 9 weeks, the problemswould most likely have been solved and therest would be assumed to roll downhill. Out-side of the scope further studies with othermonomers instead of [NVP] would be inter-esting to compare with when the ion con-ductivity tests would commence to get somesort of perspective on how functional themonomer actually is. Further a PDI (polydispersity index) analysis would be a goodidea to evaluate a more exact average molec-ular weight of the synthesized material andto observe the average chain length in thesystem. It would give a good measurementof control which RAFT is said to have. [1]

Another aspect worth looking into wouldbe the ratio of [pNVP] and [pMMA] neededto make the material rigid enough to workas a solid electrolyte, combined with thelithium salt. E.g if a longer chain of [pMMA]

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would not only affect the rigidity of the ma-terial but also if it would change the ion con-

ductivity of the electrolyte as a whole. Thesame goes for length of [pNVP], if it chainlength is extremely crucial or not.

References

[1] John Chiefari, YK Chong, Frances Ercole, Julia Krstina, Justine Jeffery, Tam PT Le,Roshan TA Mayadunne, Gordon F Meijs, Catherine L Moad, Graeme Moad, et al.Living free-radical polymerization by reversible addition-fragmentation chain transfer:the raft process. Macromolecules, 31(16):5559–5562, 1998.

[2] John Mackenzie Grant Cowie and Valeria Arrighi. Polymers: chemistry and physics ofmodern materials. CRC Press, 2007.

[3] Chih-Feng Huang, Renaud Nicolay, Yungwan Kwak, Feng-Chih Chang, and KrzysztofMatyjaszewski. Homopolymerization and block copolymerization of n-vinylpyrrolidoneby atrp and raft with haloxanthate inifers. Macromolecules, 42(21):8198–8210, 2009.

[4] Nick Greeves Jonathan Clayden and Stuart Warren. Organic Chemistry: Second Edi-tion. Oxford University Press, 2001.

[5] Vijay Kumar Patel, Avnish Kumar Mishra, Niraj Kumar Vishwakarma, Chan-dra Sekhar Biswas, and Biswajit Ray. (s)-2-(ethyl propionate)-(o-ethyl xanthate)and (s)-2-(ethyl isobutyrate)-(o-ethyl xanthate)-mediated raft polymerization of n-vinylpyrrolidone. Polymer bulletin, 65(2):97–110, 2010.

[6] Almar Postma, Thomas P Davis, Guoxin Li, Graeme Moad, and Michael S O’Shea. Raftpolymerization with phthalimidomethyl trithiocarbonates or xanthates. on the originof bimodal molecular weight distributions in living radical polymerization. Macro-molecules, 39(16):5307–5318, 2006.

[7] Xiaofeng Sui, Lennard van Ingen, Mark A Hempenius, and G Julius Vancso. Prepa-ration of a rapidly forming poly (ferrocenylsilane)-poly (ethylene glycol)-based hydro-gel by a thiol-michael addition click reaction. Macromolecular rapid communications,31(23):2059–2063, 2010.

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Appendix

Abbreviations

NVP: N-Vinyl-Pyrrolidone

MMA: Methyl Methacrylate

pNVP/pMMA: Poly-NVP/MMA.

AIBN: Azobisisobutyronitrile

DP: Degree of polymerization

PDI: Poly Dispersity Index

RAFT-: Reversible Addition-Fragmentation Chain Transfer-

MC-reagent: Michael Click-reagent

ATRP: Atom Transfer Radical-Polymerization

DCM: Dichloromethane

11

I PnMonomer

Propagation

Initisation

PnSS

Z

R S

Z

RSPn S

Z

SPn

+ + R.

..

. .

Mono

R.

PmMonomer .

Reinitiation

Propagation cont.

PnxSS

Z

R S

Z

PmxSPnx S

Z

SPnx

+ + Pmx. . .

Mono

Figure 5: RAFT mechanisms for the polymerizing systems.

12

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.0f1 (ppm)

-100000

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

1000000

1100000

1200000

1300000

1400000

1500000

1600000

1700000

1800000

1900000Renat N0 RefSingle Pulse Experiment

Figure 6: NMR Spectra of Distilled NVP Containing Dimers and Other Impurities

13

1

1

2

2

3

4

43

5

5

6

solventCDCl

6

Figure 7: NMR Spectra of Distilled and Purified NVP

14

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.0f1 (ppm)

0

500000

1000000

1500000

2000000

2500000

3000000

3500000pNVP m. Int. RefSingle Pulse Experiment

-1.0

0

Figure 8: NMR Spectra of Reference NVP with PropOH as Internal Standard

15

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.0f1 (ppm)

-100000

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

1000000

1100000

1200000

1300000

1400000

1500000

1600000pNVP m. int. S2Single Pulse Experiment

-1.0

0

Figure 9: NMR Spectra of Reference poly-NVP with PropOH as Internal Standard

16

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.0f1 (ppm)

-1000000

0

1000000

2000000

3000000

4000000

5000000

6000000

7000000

8000000

9000000

10000000

11000000

12000000

13000000

14000000pNVP m. int. S4Single Pulse Experiment

Figure 10: NMR Spectra of Final Product after Thiol Michael Click Addition

17