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Small molecule and polymer templating of inorganic materialsBrennan, Daniel P. January 2006 (has links)
Thesis (Ph. D.)--State University of New York at Binghamton, Department of Chemistry, 2006. / Includes bibliographical references.
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In vitro Condensation of Mixed-Stranded DNASantai, Catherine Theresa 20 November 2006 (has links)
DNA condensation is the process in which an anionic polymer in combination with condensing agents undergoes a drastic reduction in volume and collapses into ordered structures. Double-stranded DNA has a uniform helical secondary structure, whereas single-stranded DNA is complex and adopts numerous different conformations. Novel mixed-stranded DNA molecules, with defined regions of both single-stranded and double-stranded secondary structures attached to one another in the same molecule, were created in this body of work. Mixed-stranded DNA was designed to be intermediate between its parent secondary structures in order to discover if mixed-stranded DNA will find a balance in terms of condensation properties as well. Mixed-stranded DNA was found to condense into minimally aggregated, globular particles in the presence of low mM concentrations of divalent transition metals in aqueous solvent at room temperature, a property not observed for either pure dsDNA or ssDNA. A model is presented to describe how mixed-stranded DNA -Mn2+, -Ni2+, and -Cd2+ condensates with the observed properties are produced. Multivalent-induced condensation of mixed-stranded DNA is also characterized and found to involve an unusual rod-like morphology in order to accommodate the secondary structures condensing independent of one another at different concentrations of multivalent cations. The attachment of a ss region to an otherwise ds molecule was found to greatly influence condensation properties of the entire molecule.
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Free radical polymerization of N-vinylformamide and novel comb structure polyelectrolytes /Gu, Leming January 2001 (has links)
Thesis ( Ph.D) -- McMaster University, 2001. / Includes bibliographical references. Also available via World Wide Web.
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Synthesis and characterization of styrene – maleic anhydride copolymer derivativesMpitso, Khotso 12 1900 (has links)
Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT:
In this study, a functional styrene – maleic anhydride copolymer (SMA) was synthesized via
reversible addition-fragmentation chain transfer mediated polymerization (RAFT). The
obtained copolymer had an alternating structure with well controlled molecular weight. The
structure of the copolymer was found to alternating when characterized by NMR and
MALDI-Tof-MS.
SMA copolymer is functional polymer due to the presence of reactive maleic anhydride
moiety in its backbone. The SMA copolymer was used as a starting material for synthesis of
other three copolymers with potential anti-viral activity. These three copolymers are referred
to as SMA copolymer derivatives because they were synthesized by reacting either maleic
anhydride or styrene moieties with certain chemical compounds. The three derived
copolymers are; styrene-maleimde copolymer (SMI), styrene sulfonate-maleic anhydride
copolymer (SSMA) and styrene sulfonate– maleimide copolymer (SSMI).
SMI was synthesized by reacting 4-aminomethylbenzene sulfonamide compound with
maleic anhydride moieties on the backbone of SMA copolymer. The reaction proceeded in
the presence of co-catalysts triethylamine and dimethylamino pyridine to from amide
linkages. The copolymer was characterized by NMR spectroscopy, SEC and FTIR
spectroscopy.
SSMA copolymer was successfully synthesized by reacting styrene moieties of the SMA
copolymers with chlorosulfonic acid. The SSMA copolymer was further reacted with amine
compound to synthesize SSMI copolymer. The synthesis of SSMI was achieved by reacting
the maleic anhydride moieties in the backbone of the SSMA copolymer with N1,N1-
dimethylpropane-1,3-diamine. Both copolymers were successfully characterized by FTIR
spectroscopy. / AFRIKAANSE OPSOMMING:
'n Funksionele stireen-maleïensuuranhidried (SMA) kopolimeer is berei d.m.v. omkeerbare
addisie-fragmentasie ketting-oordrag-beheerde (OAFO) polimerisasie. Die polimere het 'n
wissellende struktuur en goed beheerde molekulêre massa gehad. Die wisselende struktuur is
bevestig d.m.v. KMR en MALDI-ToF analise.
Die SMA kopolimeer is funksioneel a.g.v. die teenwoordigheid van reaktiewe
anhidriedgroepe in die polimeerrugraat. Hierdie SMA kopolimeer is gebruik as uitgangstof
vir die bereiding van drie ander kopolimere met potensiele teenvirale-aktiwiteit: stireenmaleïimied
kopolimeer (SMI), stireensulfonaat-maleïensuuranhidried kopolimeer (SSMA)
en stireensulfonaat-maleïimied kopolimeer (SSMI). Hiedie kopolimere staan bekend as
SMA-kopolimeerderivate omdat hulle berei is deur d.m.v. die reaksie van of
maleïensuuranhidried of stireengroepe.
SMI is suksesvol berei d.m.v. die reaksie van 4-aminobenseensulfonamied met maleïensuuranhidriedeenhede
op die polimeerruggraat in die teenwoordigheid van die kokataliste
trietielamien of dimetielaminopiridien, om sodoende amiedbindings te vorm. Die kopolimere
is gekarakteriseer m.b.v. grootte-uitsluitings-chromatografie (SEC), KMR en FTIR.
Die SMMA kopolimeer is suksesvol gesintetiseer d.m.v. die reaksie van die stireeneenhede
van die SMMA kopolimeer met chlorosulfoonsuur. Die SSMA kopolimeer is verder
gereageer met amienverbindings om die SSMI kopolimeer te lewer. SMMI kopolimere is
berei d.m.v. die reaksie van die maleïensuuranhidriedgroepe in die ruggraat van die SSMA
kopolimeer met N',N'-dimetielpropaan-1,3-diamien. Albei kopolimere is suksesvol
gekarakteriseer m.b.v. KMR en FTIR.
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Organic-inorganic hybrid graft copolymers of polystyrene and polydimethylsiloxaneSutherland, Aimee Celeste 03 1900 (has links)
Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT:
Hybrid graft copolymers of polystyrene (PSty) and polydimethylsiloxane macromonomers (PDMS)
were synthesised. PSty-g-PDMS was synthesised employing the grafting through technique via a
conventionally free radical polymerization (FRP) using a polydimethylsiloxane macromonomer. In
this series the amount of PDMS incorporated into the copolymer was varied by varying the
macromonomer to styrene ratios as well as the length of the PDMS side chain. This allows for the
study of the effect that the macromonomer content and the branching length has on the efficiency
of the grafting process. A second series of PDMS-g-PSty was also synthesized where the PDMS
forms the backbone and the PSty the grafts. Two synthetic techniques were employed for the
formation of these polymers. Firstly, the grafting onto approach was used where functional
polystyrene prepolymers with either an allyl or vinyl end-groups were synthesised anionically
(living anionic polymerization) prior to the coupling of a functional prepolymer using a
hydrosilylation reaction with a Karstedt platinum catalyst. This technique was successful and gave
insight to the effect of the polystyrene prepolymer graft length has on the grafting efficiency as well
as the functional groups needed on the PDMS backbone. Furthermore, the effect of the viscosity
(of the PDMS macromonomer) plays on the grafting efficiency was also elucidated. Lastly, the
grafting from approach was employed for the formation of PDMS-g-PSty. ATRP, atom transfer
radical polymerization, of styrene using a bromoisobutyrate functional PDMS macroinitiator was
used for the synthesis of these copolymers. This was accomplished by reacting commercial silane
functional PDMS molecules via a hydrosilylation reaction (using a Karstedt catalyst) with allyl-2-
bromo-2-methyl-propionate to give a PDMS macroinitiator with bromoisobutyrate functional
groups. This will allow for the initiation and growth of polystyrene branches from the PDMS
backbone (employing ATRP with a suitable catalyst and ligand). The formation of the endproduct,
PDMS-g-PSty, via this route proved to be extremely difficult and largely unsuccessful.
Liquid chromatography (LC) at the critical point (LCCC) of polystyrene was used to separate the
graft material from homo-polymers which might have formed as well as from the PDMS
macromonomer. This technique allows for a very fast chromatographic analysis of the grafting
reaction. Under the critical conditions of PSty it was found that the graft copolymer eluted at a
lower retention time than the unreacted macromonomer and PSty homopolymer. Two-dimensional
chromatography, where LCCC (1st dimension) was coupled to size exclusion chromatography (2nd
dimension), was used for the evaluation of the CCD and MMD (molecular mass distribution) of the
graft material. LC was furthermore coupled off-line to FTIR and TEM using an LC interface. LCFTIR
gave insight to the microstructure of the material, whilst LC-TEM gave insight to the
morphological nanostructure of the material. / AFRIKAANSE OPSOMMING:
Hibried ent-kopolimere is gesintetiseer uit polistireen (PSty) en polidimetielsiloksaan (PDMS).
PSty-g-PDMS is gesintetiseer deur gebruik te maak van die ent-deur tegniek via ‘n konvensionele
vrye radikaal polimerisasie proses (VRP). In die reeks is die hoeveelheid PDMS wat geïnkorporeer
is, gevarieer deur die hoeveelheid PDMS tot PSty verhouding te verander asook die lengte van die
PDMS sytak. Gevolglik het dit toegelaat vir die studie van die effek wat die makromonomeer
inhoud, sowel as die taklengte het op die effektiwiteit van die ent-proses. ‘n Tweede reeks is ook
gesintetiseer, waar die PDMS die ruggraat vorm van die ko-polimeer, en die stireen die takke vorm
van die ko-polimeer. Dus is PDMS-g-PSty gesintetiseer. Twee sintetiese tegnieke is benut vir die
vorming van die kopolimere. In die eerste geval is daar van die ent-op tegniek gebruik gemaak
waar funksionele polistireen prepolimere met ‘n alliel of ‘n silaan end-groep gesintetiseer is deur
gebruik te maak van ‘n anioniese lewendige polimerisasie voor die koppeling van die PDMS
makromonomere deur ‘n hidrosililasie proses met ‘n Karstedt platinum katalisator. Die tegniek
was suksesvol en het in diepte insig gegee van die effek wat die molekulêre lengte van die
polistireen prepolimeer het op die effektiwiteit van die ent-proses, sowel as die minimum
hoeveelheid funksionele groepe wat teenwoordig moet wees op die PDMS ruggraat. Verder is die
effek wat die viskositeit (van die PDMS makromonomeer) op die ent-proses het, bekend gemaak.
Laastens is daar ook van die ent-vanaf tegniek gebruik gemaak vir die vorming van PDMS-g-PSty.
AORP, atoom oordrag radikale polimerisasie, van stireen, deur gebruik te maak van ‘n
bromoisobutiraat funksionele PDMS makro-inisieerder, is gebruik vir die sintese van die
kopolimere. Die makro-inisieerders is bekom deur gebruik te maak van kommersiële silaan
funksionele PDMS, en dit is gereageer deur middel van ‘n hidrosililasie proses met alliel-2-bromo-
2-metiel-propionaat. Dit het PDMS makroinisieerders tot gevolg gehad met bromoisobutiraat
funksionele groepe. Gevolglik kon stireen takke vanaf die PDMS ruggraat gegroei word deur
gebruik te maak van AORP met ‘n geskikte katalisator en ligand. Die vorming van die end-produk,
PDMS-g-PSty, deur middel van hierdie roete was onsuksesvol. Vloeistof chromatografie by die
kritiese punt van polistireen was gebruik om die ent-produk te skei van die homo-polimere en
PDMS makromonomeer. Gevolglik kon die chemiese samestelling van die ent-produk geëvalueer
word. Twee-dimensionele chromatografie, waar vloeistof chromatografie by die kritiese punt van
polistireen in die eerste vlak gekoppel was aan grootte uitsluitings chromatografie in die tweede
vlak, was benut om die chemiese komposisie sowel as die molekul re massa verdeling van die entproduk
te verkry. Verder was vloeistof chromatografie indirek aan Fourier-oordrag infrarooi en
transmissie elektron mikroskopie (TEM) gekoppel. Eergenoemde het insig gegee tot die
mikrostruktuur van die materiaal, terwyl laasgenoemde insig gegee het tot die morfologiese
nanostruktuur van die materiaal.
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Polymer-clay nanocomposites prepared by RAFT-supported graftingChirowodza, Helen 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In materials chemistry, surface-initiated reversible deactivation radical polymerisation (SI-RDRP) has emerged as one of the most versatile routes to synthesising inorganic/organic hybrid materials consisting of well-defined polymers. The resultant materials often exhibit a remarkable improvement in bulk material properties even after the addition of very small amounts of inorganic modifiers like clay.
A novel cationic reversible addition–fragmentation chain transfer (RAFT) agent with the dual purpose of modifying the surface of Laponite clay and controlling the polymerisation of monomer therefrom, was designed and synthesised. Its efficiency to control the polymerisation of styrene was evaluated and confirmed through investigating the molar mass evolution and chain-end functionality.
The surface of Laponite clay was modified with the cationic chain transfer agent (CTA) via ion exchange and polymerisation performed in the presence of a free non-functionalised CTA. The addition of the non-functionalised CTA gave an evenly distributed CTA concentration and allowed the simultaneous growth of surface-attached and free polystyrene (PS). Further analysis of the free and grafted PS using analytical techniques developed and published during the course of this study, indicated that the free and grafted PS chains were undergoing different polymerisation mechanisms. For the second monomer system investigated n-butyl acrylate, it was apparent that the molar mass targeted and the monomer conversions attained had a significant influence on the simultaneous growth of the free and grafted polymer chains. Additional analysis of the grafted polymer chains indicated that secondary reactions dominated in the polymerisation of the surface-attached polymer chains.
A new approach to separating the inorganic/organic hybrid materials into their various components using asymmetrical flow field-flow fractionation (AF4) was described. The results obtained not only gave an indication of the success of the in situ polymerisation reaction, but also provided information on the morphology of the material.
Thermogravimetric analysis (TGA) was carried out on the polymer-clay nanocomposite samples. The results showed that by adding as little as 3 wt-% of clay to the polymer matrix, there was a remarkable improvement in the thermal stability. / AFRIKAANSE OPSOMMING: Oppervlakgeïnisieerde omkeerbare deaktiveringsradikaalpolimerisasie (SI-RDRP) is een van die veelsydigste roetes om anorganiese/organiese hibriedmateriale (wat bestaan uit goed-gedefinieerde polimere) te sintetiseer. Die produk toon dikwels ʼn merkwaardige verbetering in die makroskopiese eienskappe – selfs na die toevoeging van klein hoeveelhede anorganiese modifiseerders soos klei.
ʼn Nuwe kationiese omkeerbare addisie-fragmentasie kettingoordrag (RAFT) middel met die tweeledige doel om die modifisering van die oppervlak van Laponite klei en die beheer van die polimerisasie van die monomeer daarvan, is ontwerp en gesintetiseer. Die klei se doeltreffendheid om die polimerisasie van stireen te beheer is geëvalueer en bevestig deur die molêre massa en die funksionele groepe aan die einde van die ketting te ondersoek.
Die oppervlak van Laponite klei is gemodifiseer met die kationiese kettingoordragmiddel (CTA) deur middel van ioonuitruiling en polimerisasie wat uitgevoer word in die teenwoordigheid van ʼn vrye nie-gefunksionaliseerde CTA. Die toevoeging van die nie-gefunksionaliseerde CTA het ʼn eweredig-verspreide konsentrasie CTA teweeggebring en die gelyktydige groei van oppervlak-gebonde en vry polistireen (PS) toegelaat. Verdere ontleding van die vrye- en geënte PS met behulp van analitiese tegnieke wat ontwikkel en gepubliseer is gedurende die verloop van hierdie studie, het aangedui dat die vry- en geënte PS-kettings verskillende polimerisasiemeganismes ondergaan. n-Butielakrilaat is in die tweede monomeer-stelsel ondersoek en dit was duidelik dat die molêre massa wat geteiken is en die geënte polimeerkettings.
ʼn Nuwe benadering tot die skeiding van die anorganiese/organiese hibriedmateriale in hulle onderskeie komponente met behulp van asimmetriese vloeiveld-vloei fraksionering (AF4) is beskryf. Die resultate wat verkry is, het nie net 'n aanduiding gegee van die sukses van die in-situ polimerisasiereaksie nie, maar het ook inligting verskaf oor die morfologie van die materiaal. Termogravimetriese analise (TGA) is uitgevoer op die polimeer-klei nanosaamgestelde monsters. Die resultate het getoon dat daar 'n merkwaardige verbetering in die termiese stabiliteit was na die toevoeging van so min as 3 wt% klei by die polimeermatriks.
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Synthesis of top coat surface treatments for the orientation of thin film block copolymersChen, Christopher Hancheng 08 October 2013 (has links)
Block copolymer self-assembly has demonstrated sub-optical lithographic resolution . High values of chi, the block copolymer interaction parameter, are required to achieve next-generation lithographic resolution . Unfortunately, high values of chi can lead to thin film orientation control difficulties , which are believed to be caused by large differences in the surface energy of each block relative to the substrate and the free surface. The substrate-block interface can be modified to achieve a surface energy intermediate to that of each individual block ; the air-polymer interface, however, presents additional complications. This thesis describes the synthesis of polymers for top coat surface treatments, which are designed to modify the surface energy of the air-block copolymer interface and enable block copolymer orientation control upon thermal annealing. Polymers with β-keto acid functionality were synthesized to allow polarity switching upon decarboxylation. Syntheses of anhydride containing polymers were established that provide another class of polarity switching materials. / text
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Pyridine and amine functionalized polymers by anionic and controlled free radical polymerization methodsNdawuni, Mzikayise Patrick 07 1900 (has links)
The synthesis of dipyridyl functionalized polysulfones with improved hydrophilicity, enhanced membrane morphology and excellent ATRP polymeric ligand properties was conducted by the following method:
(a) the formation of lithiated polysulfone from unmodified polysulfone and the subsequent reaction with 2,2'-vinylidenedipyridine in tetrahydrofuran at -78 oC under argon atmosphere to afford the corresponding dipyridyl functionalized polysulfone. The stoichiometry of the reaction affects the degree of functionalization of the product. When equimolar amounts of 2,2'-vinylidenedipyridine are added to the lithiated polysulfone, the degree of functionalization obtained was 45%. However, the addition of 10% and 20% molar excess of 2,2'-vinylidenedipyridine to the corresponding lithiated polysulfone produced dipyridyl functionalized polysulfones with degrees of functionalization of 80% and 95%, respectively; and
(b) the membranes obtained from unmodified polysulfone as well as dipyridyl functionalized polysulfones were characterized by atomic force microscopy, scanning electron microscopy, pure water permeation measurements and contact angle measurements.
Amine chain end functionalized polystyrene and poly(methyl methacrylate) were prepared by Atom Transfer Radical Polymerization (ATRP) methods as follows:
(a) •-Aminophenyl functionalized polystyrene was prepared in quantitative yields by ATRP methods using a new primary amine functionalized initiator adduct, formed in situ by the reaction of 1-(4-aminophenyl)-1-phenylethylene and (1-bromoethyl)benzene in the presence of copper (I) bromide/2,2'-bipyridyl as catalyst in diethyl ether at 110 oC, for the polymerization of styrene.(b) New •-bis(aminophenyl) and •,ω-tetrakis(aminophenyl) functionalized polymers were prepared in quantitative yields by the ATRP method using the following synthetic strategy:
(i) the initiation of styrene polymerization with a new primary diamine functionalized initiator adduct, generated in situ by the reaction of stoichiometric amounts of 1,1-bis(4-aminophenyl)ethylene with (1-bromoethyl)benzene in the presence of copper (I) bromide/2,2'-bipyridyl as catalyst, afforded •-bis(aminophenyl) functionalized polystyrene; and
(ii) •-bis(aminophenyl) functionalized poly(methyl methacrylate) was prepared by the ATRP method using the primary diamine functionalized initiator adduct as initiator for methyl methacrylate polymerization; and
(iii) well defined •,ω-tetrakis(aminophenyl) functionalized polystyrene was prepared by the post ATRP chain end modification reaction of •-bis(aminophenyl) functionalized polystyrene with 1,1-bis(4-aminophenyl)-ethylene at the completion of the polymerization reaction.
(c) Similarly, •-bis(4-dimethylaminophenyl) functionalized polystyrene was prepared by using a new tertiary diamine functionalized initiator adduct, formed in situ by treatment of equimolar amounts of 1,1-bis[(4-dimethylamino)phenyl]-ethylene with (1-bromoethyl)benzene in the presence of copper (I) bromide/2,2'-bipyridyl as the catalyst in diphenyl ether at 110 oC for the initiation of styrene polymerization by the ATRP method. Furthermore, the ATRP of methyl methacrylate, initiated by the new tertiary diamine functionalized initiator adduct, produced •-bis(4-dimethylaminophenyl) functionalized poly(methyl methacrylate). In addition, •,ω-tetrakis(4-dimethylaminophenyl) functionalized polystyrene was synthesized via a post ATRP chain end modification reaction of •-bis(4-dimethylaminophenyl) functionalized polystyrene with equimolar amounts of 1,1-bis[(4-dimethylamino)phenyl]ethylene at the completion of the polymerization process.
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Quantitative yields of the different amine functionalized polymers with predictable number average molecular weights (Mn = 1.3 x 103 – 16.4 x103 g/mol), narrow molecular weight distributions (Mw/Mn = 1.03 – 1.29) and controlled chain end functionality were obtained.
Polymerization kinetics data was employed to determine the controlled/living character of each ATRP reaction leading to the formation of the different amine chain end functionalized polymers. The polymerization processes were monitored by gas chromatographic analyses. Polymerization kinetics measurements for all reactions show that the polymerizations follow first order rate kinetics with respect to monomer consumption. The number average molecular weight of the amine functionalized polymers increases linearly with percentage monomer conversion and polymers with narrow molecular weight distribution were obtained.
The ATRP of styrene, catalyzed by a novel dipyridyl functionalized polysulfone/CuBr supported catalyst system, afforded well defined polystyrene with predictable number average molecular weight and narrow molecular weight distribution in a controlled/living free radical polymerization process.
The substituted 1,1-diphenylethylene initiator precursor derivatives and the functionalized polymers were characterized by nuclear magnetic resonance spectrometry, fourier transform infrared spectroscopy, thin layer chromatography, column chromatography, size exclusion chromatography, non-aqueous titrations, differential scanning calorimetry and thermogravimetrical analysis. / Chemistry / M. Sc. (Chemistry)
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Pyridine and amine functionalized polymers by anionic and controlled free radical polymerization methodsNdawuni, Mzikayise Patrick 07 1900 (has links)
The synthesis of dipyridyl functionalized polysulfones with improved hydrophilicity, enhanced membrane morphology and excellent ATRP polymeric ligand properties was conducted by the following method:
(a) the formation of lithiated polysulfone from unmodified polysulfone and the subsequent reaction with 2,2'-vinylidenedipyridine in tetrahydrofuran at -78 oC under argon atmosphere to afford the corresponding dipyridyl functionalized polysulfone. The stoichiometry of the reaction affects the degree of functionalization of the product. When equimolar amounts of 2,2'-vinylidenedipyridine are added to the lithiated polysulfone, the degree of functionalization obtained was 45%. However, the addition of 10% and 20% molar excess of 2,2'-vinylidenedipyridine to the corresponding lithiated polysulfone produced dipyridyl functionalized polysulfones with degrees of functionalization of 80% and 95%, respectively; and
(b) the membranes obtained from unmodified polysulfone as well as dipyridyl functionalized polysulfones were characterized by atomic force microscopy, scanning electron microscopy, pure water permeation measurements and contact angle measurements.
Amine chain end functionalized polystyrene and poly(methyl methacrylate) were prepared by Atom Transfer Radical Polymerization (ATRP) methods as follows:
(a) •-Aminophenyl functionalized polystyrene was prepared in quantitative yields by ATRP methods using a new primary amine functionalized initiator adduct, formed in situ by the reaction of 1-(4-aminophenyl)-1-phenylethylene and (1-bromoethyl)benzene in the presence of copper (I) bromide/2,2'-bipyridyl as catalyst in diethyl ether at 110 oC, for the polymerization of styrene.(b) New •-bis(aminophenyl) and •,ω-tetrakis(aminophenyl) functionalized polymers were prepared in quantitative yields by the ATRP method using the following synthetic strategy:
(i) the initiation of styrene polymerization with a new primary diamine functionalized initiator adduct, generated in situ by the reaction of stoichiometric amounts of 1,1-bis(4-aminophenyl)ethylene with (1-bromoethyl)benzene in the presence of copper (I) bromide/2,2'-bipyridyl as catalyst, afforded •-bis(aminophenyl) functionalized polystyrene; and
(ii) •-bis(aminophenyl) functionalized poly(methyl methacrylate) was prepared by the ATRP method using the primary diamine functionalized initiator adduct as initiator for methyl methacrylate polymerization; and
(iii) well defined •,ω-tetrakis(aminophenyl) functionalized polystyrene was prepared by the post ATRP chain end modification reaction of •-bis(aminophenyl) functionalized polystyrene with 1,1-bis(4-aminophenyl)-ethylene at the completion of the polymerization reaction.
(c) Similarly, •-bis(4-dimethylaminophenyl) functionalized polystyrene was prepared by using a new tertiary diamine functionalized initiator adduct, formed in situ by treatment of equimolar amounts of 1,1-bis[(4-dimethylamino)phenyl]-ethylene with (1-bromoethyl)benzene in the presence of copper (I) bromide/2,2'-bipyridyl as the catalyst in diphenyl ether at 110 oC for the initiation of styrene polymerization by the ATRP method. Furthermore, the ATRP of methyl methacrylate, initiated by the new tertiary diamine functionalized initiator adduct, produced •-bis(4-dimethylaminophenyl) functionalized poly(methyl methacrylate). In addition, •,ω-tetrakis(4-dimethylaminophenyl) functionalized polystyrene was synthesized via a post ATRP chain end modification reaction of •-bis(4-dimethylaminophenyl) functionalized polystyrene with equimolar amounts of 1,1-bis[(4-dimethylamino)phenyl]ethylene at the completion of the polymerization process.
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Quantitative yields of the different amine functionalized polymers with predictable number average molecular weights (Mn = 1.3 x 103 – 16.4 x103 g/mol), narrow molecular weight distributions (Mw/Mn = 1.03 – 1.29) and controlled chain end functionality were obtained.
Polymerization kinetics data was employed to determine the controlled/living character of each ATRP reaction leading to the formation of the different amine chain end functionalized polymers. The polymerization processes were monitored by gas chromatographic analyses. Polymerization kinetics measurements for all reactions show that the polymerizations follow first order rate kinetics with respect to monomer consumption. The number average molecular weight of the amine functionalized polymers increases linearly with percentage monomer conversion and polymers with narrow molecular weight distribution were obtained.
The ATRP of styrene, catalyzed by a novel dipyridyl functionalized polysulfone/CuBr supported catalyst system, afforded well defined polystyrene with predictable number average molecular weight and narrow molecular weight distribution in a controlled/living free radical polymerization process.
The substituted 1,1-diphenylethylene initiator precursor derivatives and the functionalized polymers were characterized by nuclear magnetic resonance spectrometry, fourier transform infrared spectroscopy, thin layer chromatography, column chromatography, size exclusion chromatography, non-aqueous titrations, differential scanning calorimetry and thermogravimetrical analysis. / Chemistry / M. Sc. (Chemistry)
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