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Dissertations / Theses on the topic 'Graft copolymers'
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1
Tsartolia, E. "Graft copolymers." Thesis, University of Sussex, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381632.
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Holohan, Aidan. "Polyhydroxyether-polydimethylsiloxane graft copolymers." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46823.
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Parker, James. "Graft copolymers of poly(methylphenylsilane)." Thesis, University of Kent, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274357.
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Chisholm, M. S. "Copolymers containing polydimethylsiloxane graft chains." Thesis, University of Aberdeen, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374088.
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Wilson, D. "Polyurethane-polymethyl methacrylate graft copolymers." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47306.
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Ding, Wen. "Graft copolymerization of chitosan." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/8510.
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Azam, Mohammad. "Synthesis and characterisation of polyethylene graft copolymers." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/27052.
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Graft copolymers based on a non-polar polyethylene backbone and polar poly(methyl methacrylate) (PMMA), poly(phenyl ethyl methacrylate) (PPHETMA) and poly(butyl acrylate) (PBA) side chains were synthesised by non-ionic grafting onto method. Carboxyl terminated prepolymers and hydroxyl group containing backbones were synthesised and characterised separately and then condensed in a common solvent to form a graft copolymer. Carboxyl terminated prepolymers PMMA, PPHETMA and PBA of molar masses in the range of 1400 to 4400 g mol-1 were prepared by free-radical polymerisation using 4, 4-azobis (4-cyanovaleric acid) (ACVA) as initiator and thioglycollic acid (TGA) as chain transfer agent. Backbones containing hydroxyl groups were synthesised by hydrolysing ethylene-vinyl acetate (EVA) copolymers to ethylene-vinyl alcohol (EVOH) copolymer with a VOH content of 9.8 mole %, with a VOH content of 21 mole % and a partially hydrolysed terpolymer ethylene-vinyl alcohol-vinyl acetate with a VOH content of 8.0 mole %.
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Kee, R. Andrew. "Synthesis and characterization of arborescent graft copolymers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60542.pdf.
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McCarthy, Christopher J. "Synthetic routes towards spin probe-grafted copolymers /." Online version of thesis, 1993. http://hdl.handle.net/1850/11890.
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York, Gregory A. "Structure-property relationships of multiphase copolymers." Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-07102007-142517/.
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Khadir, Abderrahim. "Applications and novel syntheses of arborescent graft copolymers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0004/NQ44768.pdf.
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Alshuiref, Abubaker. "Synthesis and characterization of urethane-acrylate graft copolymers." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/491.
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Branch, Mark G. "Comb graft copolymers : synthesis, micellisation and dispersant behaviour." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/10396.
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Styryl-terminated polystyrene macromonomers have been synthesised by the anionic polymerisation of styrene. Initiation was by sec-butyl lithium; termination involved the addition of diphenylethylene prior to vinyl benzyl chloride. Characterisation of the macromonomers was performed using gel permeation chromatography (GPC) and proton nuclear magnetic resonance spectroscopy (nmr). Novel comb graft copolymers were synthesised by the copolymerisation of the macromonomer with a comonomer. The following comonomers were used: Z-vinylpyridine (Z-VP), 4- vinylpyridine (4-VP) and N-(vinylbenzyl)pyrrolidone (VBP). Graft copolymers were made with a range of compositions by varying the feed ratios of the comonomer to the macromonomer. Reactivity ratios were determined for the different graft copolymer systems and compared to the simple statistical copolymerisation of styrene with comonomer. Characterisation of the graft copolymers was performed using GPC, nmr and membrane osmometry. Micellar dispersions of the comb graft copolymers were prepared in cyclohexane, toluene and methanol. These were subsequently characterised by small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Micellar behaviour was related to graft copolymer composition and structure. The graft copolymers were subsequently used as steric stabilisers in dispersion polymerisations of bis-hydroxyethyl terephthalate in high boiling aliphatic hydrocarbon, methyl methacrylate in cyclohexane, vinyl pyridine in toluene/cyclohexane and styrene in methanol. A number of parameters have been investigated including initiator, stabiliser and monomer concentrations. Graft copolymer composition and structure were shown to be important factors for the effective steric stabilisation of polymer particles in conjunction with information on surface coverage data.
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Xue, Wei. "Studies on zwitterionic hydrogels and cellulose graft copolymers." Thesis, University of Salford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301579.
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Horgan, Adrian. "Polystyrene nanoparticles based on block and graft copolymers." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343355.
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Sarmouk, Khiredine. "Graft copolymers and polymer electrolytes based on polyethers." Thesis, University of Aberdeen, 1990. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602307.
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This thesis is concerned with the preparation, characterisation and applications of butyl rubber (BR) with poly(tetrahydrofuran) (PTHF) and polymer electrolytes based on polyethers. The first part of this thesis is concerned with the preparation of rubber-PTHF graft copolymers by a cationic "grafting-from" reaction initiated by silver perchlorate at allylic bromine sites on the rubber. In order to optimise the content of grafted PTHF a series of experiments was carried out, in which reaction variables such as reaction temperature and time, and ratio of silver salt to active Br, were changed systematically. It was shown that an initiation period at -20C for 30 min. , followed by polymerisation at 0C with a [AgClO4]/[Br] ratio of ca. unity, produced near optimum reaction conditions with grafting efficiencies > 90%. The properties of the new BR-g-PTHF copolymers were analysed by Differential Scanning Calorimetry (DSC), Dynamic Mechanical Thermal Analysis (DMTA) and Thermogravimetry Analysis (TG). The DSC shows that all the graft copolymers have two-phase morphology comprising amorphous BR with crystalline domains of PTHF. There appears to be little interpenetration of the two phases. The DMTA suggests that the crystalline PTHF domains exert a reinforcing effect which persists from 195K up to ca. 300K at which the PTHF domains melt. TG shows that the PTHF side chains on BR function as "weak links" and reduce the thermal stability of the original rubber, This is not unexpected because it is. well known that polyethers including PEO, PPO and PTHF are susceptible to hydroperoxidation. The second part of this thesis deals with LiClO4-containing electrolytes based on PTHF and the BR-g-PTHF copolymers described above as well as a liquid EO/PO copolymer. Arrhenius plots of the conductivity and viscosity (where appropriate) are non-linear but follow the Vogel-Tamman-Fulcher (VTF) equation. PTHF-LiClO4 systems show two distinct regions in the Arrhenius plots of the conductivity ?, corresponding to temperatures below Tm (ca. 30 C) where K is very low, and above Tm where there is a marked increase in K. In the curves of molal conductivity (?) versus ?c. of both liquid polymers, ? passes through a maximum accompanied by a steep rise in viscosity, typical of coupled systems. However, the minima seen in related systems at low concentrations are absent. EO/PO-LiClO4 complexes yield electrolytes of much higher conductivities compared with the corresponding PTHF systems. Addition of 10% by weight of the plasticisers tetrahydrofuran (THF) and propylene carbonate (PC) produces a decrease in viscosity and an increase in conductivity in both types of polymer electrolyte. However, the increase in ? is relatively small on addition of THF, but very large for PC, especially at low salt concentration c. In the curves ? versus ?c the usual maximum is absent when PC is added, at a level of 10% by weight as plasticiser, and these cosolvent-salt systems appear to be "decoupled". Both PC and THF plasticise the polymer, but PC, being the solvent of higher permittivity, also interacts strongly with the salt and apparently reduces ion pairing. The conductivity of BR-g-PTHF systems depends on the type of salt and its concentrations as well as on the temperature. Thus, LiClO4 leads to complexes with BR-g-PTHF of higher conductivities than those based on NaCSN. Polymer electrolytes based on pure PTHF have higher conductivity than those derived from BR-g-PTHF. Finally, the trial prototype "supercapacitors" constructed with polyether-based electrolytes and carbon cloth TCM 128 have a higher useful voltage, ca. 2.3V, compared with those based on aqueous electrolytes. It is possible to use "solvent free" polymer electrolytes in such devices.
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Smith, Susan Abenes. "Synthesis and characterization of perfectly alternating segmented copolymers comprised of poly(dimethylsiloxane)s and engineering thermoplastics." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-03022010-020156/.
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Baleg, Abd-Almonam. "Synthesis and characterization of graft and block copolymers using hydroboration." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019/494.
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Nguyen, Duc Anh. "Cycloalkenyl macromonomers from new multifunctional inimers : a platform for graft, bottle-brush and mikto-arm star copolymers." Thesis, Le Mans, 2016. http://www.theses.fr/2016LEMA1001/document.
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Le sujet de cette thèse concerne l'élaboration de macromonomères, de copolymères greffés et de polymères étoiles de type 'mikto-arm'. De telles architectures macromoléculaires ont été synthétisées par la combinaison de techniques de polymérisation contrôlées/vivantes telles que la polymérisation par ouverture de cycle (par métathèse) (RO(M)P) etde chimie 'click' orthogonales : cycloaddition 1,3-dipolaireazoturealcyne catalysée au cuivre (CuAAC) et thiol-ène.Dans un premier temps, des macromonomères originaux à fonctionnalité polymérisable (oxa)norbornène portant deux chaînes macromoléculaires poly(e-caprolactone) (PCL) et/ou poly(oxyde d'éthylène) (POE) ont été synthétisés par combinaison ROP/CuAAC. Les macromonomères à fonctionnalité (oxa)norbornène avec deux chaînes PCL de masse molaire moyenne en nombre (Mn) compris entre 1400 et 5000 g/mol ont été obtenus par ROP organocatalysée. La synthèse des macromonomères POE44-b-PCLn à fonctionnalité norbornène avec un bloc PCL de longueur variable (1100 g/mol The objective of the present thesis was the preparation of complex macromolecules by the combination of controlled/livingpolymerization methods such as ring-opening (metathesis) polymerization (RO(M)P) and highly efficient orthogonal chemistries: copper-catalyzed azide-alkyne coupling (CuAAC) and thiol-ene reactions.In the first part of this work, a series of well-defined structural (co)polymers containing a cycloolefin (norbornene (NB) oroxanorbornene (ONB)) functionality bearing two polymer chains including poly(ε-caprolactone) (PCL) and/or poly(ethylene oxide) (PEO) have been successfully prepared using the combination of ring-opening polymerization (ROP) and CuAAC ‘click’ chemistry. Well-defined (oxa)norbornenyl-functionalized bis-PCL polymers with PCL chain ranging from 1400 to 5000 g/mol were obtained by organocatalyst-mediated ROP. Norbornenyl-functionalized PEO-b-PCL block copolymers with PCL block in the range 1100 to 4100 g/mol were synthesized from commercially available PEO 2000 g/mol by CuAAC followed by ROP of CL. The presence of a hydrophilic PEO chain and a hydrophobic PCL chain in norbornenylfunctionalizedPEO-b-PCL copolymers gives rise to self-assembling properties in water solution. Critical micellar concentrations (CMC)are in the range of 0.08 – 0.006 g/L for copolymers with PCL chain length ranging from 10 to 36 CL units, respectively. Thecorresponding micelles show hydrodynamic diameters in range of 10 – 23 nm with low polydispersities.In the second part of this work, well-defined copolymers were used to prepare bottle-brush and (mikto-arm) star copolymersthrough reactions involving the cycloolefin functionality. On the one hand, high density grafting bottle-brush copolymerspoly(oxa)norbornene-g-bisPCL, polynorbornene-g-PEO/PCL (PNB-g-(PEO/PCL)) and PNB-b-(PNB-g-(PEO/PCL)) were achieved by ROMP according to the ‘grafting through’ strategy using Grubbs’ catalysts. On the other hand, PCL, PEO, PNIPAM-based 3-arms star, 4-arms star copolymers were obtained via radical thiol-ene reactions as demonstrated by 1H NMR, SEC and MALDI-ToF MS analysis.The high reactivity of these copolymers toward ROMP and thiol-ene reactions makes them interesting candidates in order toprepare new well-defined copolymers with controlled structures and properties through highly efficient synthetic strategies
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Pasche, Stéphanie. "Mechanisms of protein resistance of adsorbed PEG-graft copolymers /." Zürich, 2004. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15712.
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Irving, Matthew D. "Synthesis and characterisation of poly(vinyl butyral) graft copolymers." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/11790.
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Graft copolymers based on a poly(vinyl butyral)(PVB) backbone were prepared using a non-ionic grafting onto procedure. Monofunctionalised poly( methyl methacrylate)(PMMA) and poly(phenyl ethyl methacrylate)(PPEMA) were prepared using a matched free radical initiator and chain transfer system of 4,4 '-azobis-4-cyano valeric acid (ACV A) and thioglycollic acid (TGA) respectively. By changing the concentration of TGA, two series of prepolymers having molecular masses from 1400 to 4300 g mor1 were prepared. The carboxylic acid groups at the chain ends of prepolymers were then converted to the corresponding acid chloride groups. These were reacted onto the PVB backbone by a condensation reaction with some of the hydroxyl groups on the PVB. The PVB was chosen so that 21% of the polymer was vinyl alcohol, 3% was vinyl acetate and the remainder was vinyl butyral. Reaction conditions were chosen carefully, because PVB was known to aggregate in solution, and this ensured that grafting frequencies up to 10 grafts per chain were achieved. The PVB backbone, prepolymers and graft copolymers were all characterised so that the full architecture of the final graft copolymer was known. GPC was used, relative to a polystyrene calibration plot, to obtain molecular mass distributions of polymers. However, PVB and graft copolymers were seen to aggregate and this resulted in erroneously high molecular mass values. IR spectroscopy was used qualitatively and quantitatively so that the types of bonds and grafting frequencies could be obtained. 1H and 13C NMR spectroscopy were used qualitatively and 1H NMR spectroscopy was used quantitatively so that prepolymer molecular masses and graft copolymer grafting frequencies could be determined. Solution viscometry was used to obtain intrinsic viscosities of all polymers in solution. This showed that the GPC results were correct and that the main method of separation was due to size exclusion. Slope constants from Huggins and Kraemer plots suggested that PVB and graft copolymers formed aggregates in solution. Laser light scattering was used but Zimm plots obtained were markedly curved and this provides evidence to the existence of aggregates in solution.
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Sagoo, P. S. "Vapour transport in natural rubber blends and graft copolymers." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37842.
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Sutherland, Aimee Celeste. "Organic-inorganic hybrid graft copolymers of polystyrene and polydimethylsiloxane." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/3182.
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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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Hu, Nan. "Block and Graft Copolymers Containing Carboxylate or Phosphonate Anions." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/70877.
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This dissertation focuses on synthesis and characterization of graft and block copolymers containing carboxylate or phosphonate anions that are potential candidates for biomedical applications such as drug delivery and dental adhesives.
Ammonium bisdiethylphosphonate (meth)acrylate and acrylamide phosphonate monomers were synthesized based on aza-Michael addition reactions. Free radical copolymerizations of these monomers with an acrylate-functional poly(ethylene oxide) (PEO) macromonomer produced graft copolymers. Quantitative deprotection of the alkylphosphonate groups afforded graft copolymers with zwitterionic ammonium bisphosphonate or anionic phosphonate backbones and PEO grafts. The zwitterionic copolymers spontaneously assembled into aggregates in aqueous media. The anionic copolymers formed aggregates in DMF and DMSO, while only small amounts of aggregates were present in copolymer/methanol or copolymer/water solutions. Binding capabilities of the acrylamide phosphonic acids were investigated through interactions with hydroxyapatite.
Previously our group has prepared poly(ethylene oxide)-b-poly(acrylic acid) (PEO-b-PAA) copolymers and used these polymers as carriers for both MRI imaging agents and cationic drugs. To enhance the capabilities of those carriers in tracking and crosslinking, we have designed, synthesized and characterized amine functionalized PEO-b-PAA copolymers. First, heterobifunctional poly(ethylene oxide) (PEO) with three different molecular weights were synthesized. Modification on one of these afforded a PEO macroinitiator with a bromide on one end and a protected amine on the other end. ATRP polymerization of tert-butyl acrylate (tBuA) in the presence of this initiator and a copper (I) bromide (CuBr) catalyst yielded a diblock copolymer. The copolymer was deprotected by reaction with trifluoroacetic acid (TFA) and formed an amine terminated H2N-PEO-b-PAA.
Recently our group has utilized the novel ammonium bisdiethylphosphonate (meth)acrylate and acrylamide phosphonate copolymers to incorporate Carboplatin. The resulting complexes exhibited excellent anticancer activity against MCF-7 breast cancer cells which might be related to ligand exchange of the dicarboxylate group of Carboplatin with the phosphonic acid moieties in the copolymer. Hence, complexation of small-molecule phosphonic acids with Carboplatin was investigated. Three compounds, vinylphosphonic acid, 3-hydroxypropyl ammonium bisphosphonic acid and 2-hydroxyethyl ammonium phosphonic acid were complexed with Carboplatin under acidic and neutral conditions. Covalent bonding of these acids to carboplatin was only observed under acidic pH. The covalently bonded percentage was 17%, 37% and 34%, respectively. More in-depth investigation was of great importance to further understand this complexation behavior.Ph. D.
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Swanson, Nicole. "Polybutadiene Graft Copolymers as Coupling Agents in Rubber Compounding." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1473158881.
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Teramoto, Yoshikuni. "Structural Designing and Functionalization of Biodegradable Cellulosic Graft Copolymers." Kyoto University, 2004. http://hdl.handle.net/2433/147753.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第10904号
農博第1410号
新制||農||890(附属図書館)
学位論文||H16||N3915(農学部図書室)
UT51-2004-G751
京都大学大学院農学研究科森林科学専攻
(主査)教授 西尾 嘉之, 教授 中坪 文明, 教授 松本 孝芳
学位規則第4条第1項該当
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Postma, Almar School of Chemical Engineering & Industrial Chemistry UNSW. "Approaches to the synthesis of block and graft copolymers with well defined segment lengths." Awarded by:University of New South Wales. School of Chemical Engineering and Industrial Chemistry, 2005. http://handle.unsw.edu.au/1959.4/32822.
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The synthesis of amine end-functionalised polymers by controlled free radical techniques has been investigated with a focus on methods that provide primary amino end-functionalised polystyrene. The aim of these investigations was to provide precursors to block and graft polyolefins and polyesters by interchain coupling reactions. The approaches investigated involved developing strategies for the synthesis of phthalimido-functional polymers which can be quantitatively deprotected to yield the desired amino-functional polymers. Initially synthesis by atom transfer radical polymerisation (ATRP) was explored. A number of approaches based on ??-functionalisation (end-group substitution) and ??-functionalisation (functional initiator) were examined. A novel ATRP initiator, N-bromomethylphthalimide, provided the most promising results but still had limited applicability because of its low solubility in polymerisation media. The problems encountered with the ATRP approaches prompted an exploration of techniques based on reversible addition fragmentation chain transfer (RAFT) approach. Novel phthalimidomethyl RAFT agents (trithiocabonates, xanthates) were synthesized. The activity and scope of the new RAFT agents was investigated in polymerisations of styrene, n-butyl acrylate, Nisopropylacrylamide, N-vinylpyrrolidone (trithiocarbonate) and vinyl acetate (xanthate). The syntheses of ??-phthalimidomethylpolystyrene were successfully scaled up and hydrazinolysis afforded a range of ??- aminomethylpolystyrenes of low polydispersity and controlled molecular weight. The syntheses of primary amino-functional polymers using the pthalimidofunctional RAFT agents necessitated the development of a convenient method for conversion of trithiocarbonate groups to inert chain ends. Thermolysis proved a most simple and efficient method of achieving this for both polystyrene and poly(n-butyl acrylate). Thermolysis also provided a means of further characterising the mechanism of the RAFT process. A simple and efficient method for amino end-group analysis was developed that involved in-situ derivatisation with trichloroacetyl isocyanate followed by 1H NMR analysis. The method was shown to be a suitable method for determining a wide range protic end-groups (NH2, OH, COOH) in synthetic polymers. Finally, metallocene polyolefin based coupling trials largely with controlled amino-functional polystyrene were conducted as an initial investigation into the production of high value added grafted polyolefins (and polyester). The grafting trials were carried out on a small scale with a view to directing future experiments.
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Lian, Qing. "Structural investigation of a mesogen-chitosan graft copolymer system." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/8598.
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Kaufman, Michael Steven. "Radical-mediated modification of polyolefins: investigation of the synthesis of graft copolymers." Thesis, Kingston, Ont. : [s.n.], 2008. http://hdl.handle.net/1974/1201.
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Chen, Guangde. "A New Approach to the Synthesis of PVC Graft Copolymers." W&M ScholarWorks, 2005. https://scholarworks.wm.edu/etd/1539626839.
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Ma, Yanhui. "Graft copolymer micelles and surface modification with polymer micelles /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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Duddington, Philip. "Studies of dispersant behaviour of graft copolymers in non-aqueous media." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/27841.
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Free radical polymerisation with matched initiator and chain transfer agent has been used to produce carboxyl-terminated poly(2-ethylhexyl acrylate) homopolymers of controlled molar mass. These polymers were monofunctional with respect to carboxyl groups. The carboxyl terminated polymers were converted to methacrylate macromonomers via one of two methods. The first route used an acyl chloride intermediate. The second involved an epoxide ring opening reaction. The acyl chloride method gave macromonomers with high functionality (>0.9), whilst the epoxide method gave typical functionalities of 0.5. The macromonomers were characterised by Gel Permeation Chromatography (GPC), Fourier Transform Infra-Red (FTIR) and Proton Nuclear Magnetic Resonance (1 H NMR) spectroscopy.
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Rizmi, Abdul Cassim Mohamed. "Synthesis, characterisation and properties of some well-defined comb graft copolymers." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/5057/.
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This thesis describes studies directed to the ring opening metathesis polymerisation of macromonomers and mesogenic monomers to produce graft copolymers and side chain liquid crystalline polymers respectively. The necessary background information relevant to the work described in this thesis is presented in chapter-1 and consists of four sections; namely, descriptions of metathesis polymerisation, anionic polymerisation, synthesis of graft copolymers and synthesis of side chain liquid crystalline polymers. The synthesis of the end capping reagent exo-5-norbomene-2- carbonyl chloride is described in chapter-2. The synthesis and characterisation of exo- 5-norbomene-2-poly(styrylcarboxylate) macromonomers by living anionic polymerisation is discussed in chapter-3. Chapter-4 reports the synthesis, characterisation and properties of graft copolymers prepared by ring opening metathesis polymerisation of exo-5-norbomene-2-poly(styrylcarboxylate) macromonomers. Chapters-5 describes the synthesis of the mesogenic monomer; (5)- (-)-2-methylbutyl-4-(4-(l 0-(3-cyclopentenylmethoxy) decyloxy) phenylcarbonyloxy) benzoate, suitable for ring opening metathesis polymerisation to produce side chain liquid crystalline polymer. The attempted synthesis of side chain liquid crystalline polymer by ring opening metathesis polymerisation of the mesogenic monomer; (5)-(- )-2-methylbutyl-4-(4-( 10-(3 -cyclopentenylmethoxy) decyloxy) phenylcarbonyloxy) benzoate is reported in chapter-6. Finally chapter-7 summarises the conclusions and makes some suggestions for future work.
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Williams, Rebecca J. "Synthesis and self-assembly of linear and cyclic degradable graft copolymers." Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/69964/.
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This thesis explores the use of ring-opening polymerisation (ROP) and reversible addition-fragmentation chain transfer (RAFT) polymerisation to prepare linear and cyclic graft copolymers with a polycarbonate backbone. The solution properties and self-assembly behaviour of these linear and cyclic graft copolymers with hydrophilic side arms is also described. Chapter 1 introduces the polymerisation techniques used in this thesis, namely ROP and RAFT, and provides a review of the self-assembly of polymers that possess a cyclic topology. In Chapter 2, the synthesis and ROP of a novel cyclic carbonate monomer bearing pendent norbornene functionality is described. Successful postpolymerisation modification of the norbornene functionality is demonstrated for a range of addition reactions; 1,3-dipolar cycloaddition, inverse electron demand Diels-Alder reaction and radical thiol-ene addition, and is also shown to provide access to multi-functional polycarbonates. Attempts to prepare graft copolymers via the grafting of thiol-terminated polymer chains to the norbornene-functional polycarbonate backbone are also described. Chapter 3 describes the optimised synthesis of linear graft copolymers via the ROP of a RAFT chain transfer agent (CTA)-functional cyclic carbonate monomer and subsequent RAFT polymerisation to grow polymer chains from the RAFT CTA sites located along the resulting polycarbonate backbone. This methodology was used to prepare a polycarbonate-g-poly(Nisopropylacrylamide) amphiphilic copolymer and its self-assembly to afford degradable, thermoresponsive particles is demonstrated. In Chapter 4, the optimised procedures developed in Chapter 3 for the preparation of linear graft copolymers are applied to the preparation of welldefined cyclic graft copolymers with a degradable cyclic polycarbonate backbone and a range of side arm compositions. Chapter 5 investigates the solution properties and self-assembly behaviour of linear and cyclic graft copolymers with hydrophilic poly(N-acryloylmorpholine) side arms and a hydrophobic polycarbonate backbone, prepared using the methodologies developed in Chapters 3 and 4. Chapter 6 provides a summary of the key findings of Chapters 2 – 5 and Chapter 7 provides the experimental methods of this thesis.
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MacDonald, Iain I. "Synthesis, structural and adhesive evaluation of novel graft meth(acrylate) copolymers." Thesis, University of Strathclyde, 2011. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=15334.
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Krugel, Gretha. "Synthesis and characterisation of hybrid graft copolymers of polydimethylsiloxane and polymethylmethacrylate." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/2224.
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Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2007.Hybrid graft copolymers of polydimethylsiloxane (PDMS) and polymethylmethacrylate (PMMA) were synthesised. PDMS macromonomers were synthesised anionically from the cyclic D3 monomer. This living polymerisation was terminated with a [3- (methacryloxy)propyl]-dimethylchlorosilane terminating agent which resulted in the functionalised macromonomer. These PDMS macromonomers and MMA monomer were copolymerised to form PMMA-g-PDMS hybrid copolymers by conventional free radical reactions. Synthesised and commercial methacryloxy-functionalised PDMS macromonomers having a range of molar masses were copolymerised with MMA to form graft copolymers of various chemical compositions. PDMS content in the graft copolymers could be varied by the amount of PDMS incorporated into the copolymer as well as by varying the length of the PDMS side chains. Size exclusion chromatography (SEC) results confirmed low PDI’s for the PDMS macromonomers synthesised anionically. NMR studies allowed characterisation of the synthesised PDMS macromonomers and PMMA-g-PDMS copolymers. It also allowed the determination of relative ratios of PMMA:PDMS in the graft copolymers. Gradient elution chromatography (GEC) was used successfully to monitor the presence and removal of the PDMS macromonomer from the graft copolymer products. The influence of PDMS content of the graft copolymers on retention time was also evaluated using this technique. Two dimensional chromatography confirmed the formation of PMMA-g-PDMS copolymer as well as PMMA homopolymer during some of the grafting reactions. GEC in the first dimension was coupled to SEC in the second dimension. PAS-FTIR studies allowed chemical characterisation of the graft copolymer and confirmed surface segregation of the PDMS. Atomic force microscopy (AFM) was also used to study the surface segregation of PDMS and looked at the relationship between surface polarity and increasing PDMS content. The study showed the effect of thermal treatment on the surface morphology of the hybrid polymers. Corona treatment was used to modify the surface structure of the graft copolymer films. Contact angle studies provided evidence of hydrophobic loss and recovery after corona for the hybrid polymer materials containing PDMS. This is one of the first reported examples of hydrophobicity recovery in these types of hybrid materials after corona treatment. Slow positron beam studies highlighted the formation of a thin silica like layer on the surface of the films after corona similar to that observed for pure cross-linked PDMS compounds. The positron studies enabled estimation of the thickness of the silica like layer.
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York, Greg Allen. "TEM/EDXS studies of phase separation in block and graft copolymers." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/80085.
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The relationships between molecular parameters and microdomain formation of a variety of block- and graft-copolymers were studied by Transmission Electron Microscopy (TEM). Molecular variables included chemical composition: dimethyl-, fluoropropyl and diphenyl-siloxane , sulfone styrene, paramethylstyrene, t-butylstyrene, arylester and methyl methacrylate, as well as molecular weight and distribution. Effects of the kinetics of phase-separation were also determined . Thick (approximately lmm) films cast from solvent showed more complete phase separation than either thin (about 10nm) cast films or compression-molded specimens.
Spherical domains formed in alternating poly(ester/siloxanes), and phase mixing seemed to correlate with the solubility parameters of the three siloxane types. Shear-stresses during molding changed domain shapes and eliminated short-range ordering. In the PMMA-graft-dimethyl siloxane system, SK, 10K and 20K Master of Science
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Breitenkamp, Rebecca Boudreaux. "Oligopeptide-functionalized Graft Copolymers: Synthesis and Applications in Nucleic Acid Delivery." Amherst, Mass. : University of Massachusetts Amherst, 2009. http://scholarworks.umass.edu/open_access_dissertations/5/.
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Shah, Jignesh. "Solid phase graff copolymerization of maleic anhydride onto polyethylene and polystyrene /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418062.
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Smith, Steven D. "Synthesis of novel siloxane-containing block and graft copolymers by anionic polymerization and the macromonomer technique." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/74770.
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The synthesis of novel well defined graft copolymers is now possible with the recent advent of the macromonomer technique. Copolymers with narrow molecular weight distributions of the backbone as well as the grafts are possible.
The anionic alkyl- lithium initiated ring opening polymerization of the hexamethylcyclotrisiloxane has been investigated to prepare polymers of controlled molecular weights and narrow molecular weight distributions. This technique was extended to the preparation of macromonomers and from these macromonomers the synthesis of graft copolymers.
These siloxane macromonomers were then incorporated into acrylic and styrenic copolymers via free radical and anionic techniques. A series of graft copolymers were characterized by a variety of methods. The resulting copolymers exhibit interesting thermal properties dependent on graft molecular weight and composition. Well-defined morphologies were observed by TEM analysis, indicative of the unique structures prepared.
Graft copolymers offer unique possibilities of structure property relationships, often forming two phase morphologies that give rise to properties of both constituents. This allows the preparation of polymers designed to give optimal characteristics.Ph. D.
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Stegmann, Jacobus Christiaan. "RAFT-mediated synthesis of graft copolymers via a thiol-ene addition mechanism." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/18700.
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Thesis (MSc)--University of Stellenbosch, 2007.ENGLISH ABSTRACT: The main objective of this project was the controlled synthesis of graft copolymers via a thiol-ene addition mechanism. The Reversible Addition-Fragmentation chain Transfer (RAFT) process was used in all polymerization reactions with the aim to achieve a certain degree of control over the molecular weight. Several synthetic steps were required in order to obtain the final graft copolymer and each step was investigated in detail. Firstly, two RAFT agents (cyanovaleric acid dithiobenzoate and dodecyl isobutyric acid trithiocarbonate) were synthesized to be used in the various polymerization reactions of styrene and butyl acrylate. This was done successfully and the RAFT agents were used to synthesize low molecular weight polystyrene branches of the graft copolymer. Different molecular weights were targeted. It was found that some retardation phenomena were present especially at high RAFT agent concentrations. The polystyrene branches that were synthesized contained RAFT end-groups. Various pathways were explored to modify these RAFT end-groups to form thiol end-groups to be used in the thiol-ene addition reaction during the grafting process. The use of sodium methoxide for this purpose proved most successful and no evidence of the formation of disulfide bridges due to the initially formed thiols was detected. Allyl methacrylate (AMA) was chosen as monomer to be used for the synthesis of the polymer backbone because it has two double bonds with different reactivities. For the first time, RAFT was used to polymerize AMA via the more reactive double bond to obtain linear poly(allyl methacrylate) (PAMA) chains with pendant double bonds. However, at higher conversions, gelation occurred and the molecular weight distributions were uncontrolled. NMR was successfully used to study the tacticity parameters of the final polymer. Finally, the synthesis of the graft copolymer, PAMA-g-polystyrene, was carried out by means of the “grafting onto” approach. The thiol-functionalized polystyrene branches were covalently attached to the pendant double bonds of the PAMA polymer backbone via a thiol-ene addition mechanism in the presence of a free radical initiator. A Multi- Angle Laser Light Scattering (MALLS) detector was utilized in conjunction with Size- Exclusion Chromatography (SEC) to obtain molecular weight data of the graft copolymer. The percentage grafting, as determined by 1H-NMR, was low.
AFRIKAANSE OPSOMMING: Die hoofdoel van hierdie projek is die beheerde sintese van ‘n entkopolimeer via ‘n merkaptaan-een addisiereaksie. Die sogenaamde “Reversible Addition-Fragmentation chain Transfer” (RAFT) proses is in al die polimerisasiereaksies gebruik met die doel om ‘n mate van beheer oor die molekulêre massa van die polimere te verkry. Verskeie stappe (waarvan elkeen ten volle ondersoek is) was nodig om die finale entkopolimeer te verkry. Eerstens is twee RAFT-agente (sianovaleriaansuur ditiobensoaat en dodekielisobottersuur tritiokarbonaat) gesintetiseer vir gebruik in verskeie polimerisasiereaksies van stireen en butielakrilaat. Hierdie stap was suksesvol en die RAFT-agente is toe gebruik vir die sintese van lae molekulêre massa polistireensytakke vir die entkopolimeer. Die molekulêre massas van die sytakke is gevarieer en daar is gevind dat vertragings in die polimerisasiereaksies voorgekom het, veral by hoë konsentrasies van die RAFT-agente. Die polistireensytakke wat gemaak is, besit almal ‘n RAFT-eindgroep. Verskeie roetes is bestudeer ten einde die RAFT-eindgroepe tot merkaptaan-eindgroepe te modifiseer om sodoende tydens ‘n merkaptaan-een addisiereaksie gebruik te word. Die gebruik van natriummetoksied was hier die suksesvolste en daar was geen teken van die vorming van disulfiedbrûe as gevolg van die oorspronklik gevormde merkaptane nie. Allielmetakrilaat (AMA) is gekies as die monomeer wat gebruik sou word vir die sintese van die polimeerruggraat omdat die monomeer twee dubbelbindings met verskillende reaktiwiteite besit het. Vir die eerste keer is RAFT gebruik vir die polimerisasie van AMA via die meer reaktiewe dubbelbinding om lineêre poli(allielmetakrilaat) (PAMA) kettings met dubbelbindings in die sygroepe te verkry. Gelvorming en onbeheerde molekulêre massaverspreiding het egter by hoër monomeeromsettings voorgekom. KMR is susksekvol gebruik om die taktisiteitsparameters van die finale polimeer te bestudeer. Ten slotte is die sintese van die entkopolimeer, PAMA-g-polistireen, uitgevoer deur die aanhegting van voorafgevormde sytakke. Die polistireensytakke met die merkaptaaneindgroepe is kovalent geheg aan die dubbelbindings in die sygroepe van die PAMA-polimeerruggraat via ‘n merkaptaan-een addisiemeganisme in die teenwoordigheid van ‘n vrye radikaalinisieerder. ‘n Kombinasie van gelpermeasiechromatografie en multi-hoeklaserligverstrooiing is gebruik om die molekulêre massa van die entkopolimeer te bepaal. Die persentasie sytakke soos bepaal deur 1H-KMR was laag.
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Virtanen, Janne. "Self-assembling of thermally responsive block and graft copolymers in aqueous solutions." Helsinki : University of Helsinki, 2002. http://ethesis.helsinki.fi/julkaisut/mat/kemia/vk/virtanen/.
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Hoover, James Matthew. "Morphological effects on gas transport through poly(methylmethacrylate)-poly(dimethlysiloxane) graft copolymers and instrumentation for their synthesis and permeability characterization." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/77800.
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During the past few years, studies involving the synthesis, characterization, and structure-property relations of especially well-defined or "model" block and graft copolymers have received increasing interest among academic and industrial communities. The well-defined nature of such polymers makes them ideal subjects for both fundamental studies and specialty polymer applications.
This study addresses the synthesis and characterization of well-defined block and graft copolymers through the use of reactor systems and permeability instrumentation designed specifically for this purpose. The engineering design, construction, operation, and in some cases automation of the above instrumentation is discussed in detail. Examples of the synthesis and permeability characterization of several especially interesting multiphase graft and star block copolymers are provided to demonstrate the utility of the instrumentation described. The primary focus of this work has been to address the effects of varying degrees of microphase separation and morphological development on the physical properties of well-defined block and graft copolymers and their hydrogenated derivatives. The application of gas permeability as an especially sensitive probe of morphology in well-defined poly(methylmethacrylate) -poly(dimethylsiloxane) graft copolymers has been given special emphasis.
The synthesis these graft copolymers has been accomplished by the copolymerization of model, methacrylate-functional, poly(dimethylsiloxane) CPDMS) "macromonomers" with methylmethacrylate, using conventional free-radical and novel anionic and group transfer techniques. These techniques are described and referenced with chemical characterization provided. The resulting graft copolymers have PDMS-modified surface and bulk morphologies that dominate particular physical property responses and provide for interesting structure-permeability studies. The characterization of these copolymers to demonstrate their well-defined nature has been performed with a focus on the application of gas permeability as an especially sensitive morphological probe.
A review of the relevant literature is followed by detailed experimental procedures, a summary and discussion of results, and descriptive appendices. The appendices include details concerning the design, fabrication, and automation of instrumentation to perform volumetric, equilibrium sorption experiments and computer programs for the acquisition and analysis of permeability data.Ph. D.
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Hudda, Laila B. "Origin of limiting conversion phenomenon in alkyd/acrylate graft copolymerization systems." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/10960.
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Basson, Neil. "Free volume of electrospun organic-inorganic copolymers." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86676.
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Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Two series of amphiphilic, organic-inorganic graft copolymers of poly(methyl methacrylate) and poly(dimethylsiloxane) (PMMA-graft-PDMS), as well as poly(acrylonitrile) and poly(dimethylsiloxane) (PAN-graft-PDMS), were synthesized via conventional free radical copolymerization using the ―grafting through‖ technique. In both series the PDMS macromonomer content varied from 5 wt.% - 25 wt.% and different graft lengths of 1000 g/mol and 5000 g/mol were used. A gradient elution profile was developed to monitor the removal of the unreacted PDMS macromonomer using hexane extraction. In the case of the PAN copolymer series, the gradient profile showed that as the PDMS content in the feed increased, more PAN-graft-PDMS molecules formed relative to homopolymer PAN. In the case of the PMMA copolymer series, mostly PMMA-graft-PDMS molecules were formed as the PDMS content in the feed increased. In the case of the PAN-graft-PDMS series, the PDMS content affected the crystallization behaviour of the PAN segments and lead to a decrease in crystallinity across the composition range as the PDMS content increased. It is shown that the synthesized graft copolymers can be electrospun to produce continuous nanofibers. The effects of polymer solution concentration, copolymer composition and tip-to-collector distance on the fiber morphology are discussed. The rapid stretching of the polymer jet, as well as the rapid solvent evaporation during the electrospinning process, resulted in highly complex nonequilibrium morphologies in the case of the electrospun PAN-graft-PDMS copolymers. The crystallization behaviour of the electrospun fibers of PAN-graft- PDMS was shown to be different from the unprocessed precursor material. Surface oxidised MWCNTs were successfully incorporated and well dispersed into the graft copolymers via the electrospinning process to produce nanocomposite nanofibers. In the case of the PAN-graft-PDMS copolymer series, the presence of MWCNTs in the nanocomposite nanofibers enhanced the overall degree of crystallinity when compared to the unfilled nanofibers. For the first time positron annihilation lifetime spectroscopy (PALS) analysis was performed on the various complex graft copolymer compositions and their electrospun fiber analogues, as well as nanocomposites, to investigate the free volume properties of the various materials. The results revealed that there are two distinct ortho-positronium (o-Ps) lifetime parameters for these complex multiphased materials. The shorter lived lifetime -3 was attributed to the o-Ps annihilation in the amorphous regions of the crystalline PAN phase in the PAN-graft-PDMS copolymer series, as well as to the o-Ps annihilation in the amorphous PMMA phase in the case of the PMMA-graft-PDMS copolymer series. The longer lived lifetime -4 was attributed to the o-Ps annihilation in the more amorphous PDMS phase. In the case of the PMMA series the relative fractional free volume was influenced by the graft lengths, where the 5000 g/mol series showed a larger increase in fractional free volume relative to the shorter 1000 g/mol series. The effects of the tip-to-collector distance during electrospinning, as well as the inclusion of MWCNTs, on the free volume properties are also discussed. It is demonstrated how positron annihilation lifetime spectroscopy can provide valuable and unique information on the internal structure and morphology of the electrospun nanofibers.
AFRIKAANSE OPSOMMING: Twee reekse amfifiliese, organies-anorganiese entkopolimere van poli(metielmetakrilaat) en poli(dimetielsiloksaan) (PMMA-ent-PDMS), asook poli(akrilonitriel) en poli(dimetielsiloksaan) (PAN-ent-PDMS), is gesintetiseer deur konvensionele vrye-radikaalkopolimerisasie. Die PDMS makromonomeerinhoud het gewissel tussen 5 wt.% - 25 wt.% in albei reekse en sykettinglengtes van 1000 g/mol en 5000 g/mol is gebruik. `n Gradient-eluasieprofiel is opgestel om die verwydering van ongereageerde PDMS makromonomeer d.m.v. heksaanekstraksie te monitor. In die PAN kopolimeer reeks het die gradient-eluasieprofiel gewys dat meer PAN-ent- PDMS molekules vorm relatief tot die PAN homopolimeer sodra meer PDMS bygevoeg word. In die PMMA kopolimeer reeks het meer PMMA-ent-PDMS molekules gevorm sodra meer PDMS toegevoeg is. In die geval van die PAN-ent- PDMS reeks, het die PDMS die kristallisasiegedrag van die PAN segmente geaffekteer en `n afname in die totale kristalliniteit veroorsaak soos die PDMS inhoud vermeerder het. Daar word bewys dat die gesintetiseerde entkopolimere geelektrospin kan word om nanovesels te vorm. Die effek van polimeeroplossingskonsentrasie, kopolimeersamestelling en punt-tot-versamelaarafstand op die nanoveselmorfologie word bespreek. Die vinnige strekking van die polimeerjet sowel as die vinnige verdamping van die oplosmiddel gedurende die elektrospinproses het gelei tot hoogs komplekse nie-ekwilibrium morfologieë in die geval van die ge-elektrospinde PAN-ent-PDMS kopolimere. Die kristallisasiegedrag van die nanovesels van PAN-ent-PDMS het verskil van die onverwerkte voorloper materiaal. Oppervlakgeoksideerde MWCNTs is suksevol geïnkorporeer en versprei in die entkopolimere d.m.v. die elektrospinproses om nanosaamgestelde nanovesels te vorm. Die teenwoordigheid van MWCNTs in die nanosaamgestelde nanovesels in die PAN-ent-PDMS kopolimeerreeks het gelei tot `n verbetering in die algehele kristalliniteit in vergelyking met die nanovesels sonder MWCNTs. Positronvernietigingsleeftyd- spektroskopie (PALS) is vir die eerste keer gebruik om die vrye volume van verskillende kompleks entkopolimeersamestellings, hul ge-elektrospinde nanovesels sowel as nanosaamgestelde nanovesels te bestudeer. Die resultate het getoon dat daar twee verskillende orto-positronium (o-Ps) leeftydparameters vir hierdie komplekse multifase materiale bestaan. Die korter leeftydparameter -3 word toegeskryf aan die o-Ps vernietiging in die amorfe areas van die kristallyne PAN fase in die PAN-ent-PDMS kopolimeerreeks, sowel as die o-Ps vernietiging in die amorfe PMMA fase in die PMMA-ent-PDMS kopolimeerreeks. Die langer leeftydparameter -4 word toegeskryf aan die o-Ps vernietiging in die amorfe PDMS fase. Die relatief fraksionele vrye volume van die PMMA reeks is deur die verskillende syketting lengtes beïnvloed. Die 5000 g/mol syketting het `n groter toename in fraksionele vrye volume veroorsaak relatief tot die korter 1000 g/mol syketting. Die effek van die punttot- versamelaar-afstand tydens die elektrospinproses op die vrye volume eienskappe, sowel as die insluiting van MWCNTs, word bespreek. Daar word aangedui hoe positron-vernietigingsleeftyd-spektroskopie waardevolle en unieke inligting kan verskaf oor die interne struktuur en morfologie van die nanovesels.
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Sheridan, Matthew Stanley. "Well defined graft copolymers and end functional materials: synthesis, characterization and adhesion studies." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/40414.
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Miller, Aline Fiona. "Organisation and dynamics of well-defined graft copolymers at the air-water interface." Thesis, Durham University, 2000. http://etheses.dur.ac.uk/4226/.
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Novel amphiphilic graft copolymers with a backbone of poly(norbornene) (PNB) with poly(ethylene oxide) (PEO) grafts have been synthesised by a combination of ring opening metathesis and anionic polymerisation methods. The polymer has been prepared with hydrogenous and deuterated grafts and with grafts of different degrees of polymerisation. These graft copolymers spread at the air-water and air-PEO solution interface forming thin films and their organisation and dynamic behaviour is discussed. Monolayer behaviour was characterised from surface pressure isotherms and it was demonstrated that the shape of the isotherm is dependent on graft length and on the concentration of PEO in the subphase. Using neutron reflectometry the organisation of such spread films at the air-water interface have been obtained over a range of surface concentrations for each length of PEO graft. Data were analysed by both exact calculation methods and the partial kinematic approximation and the models adopted were verified by applying the model independent Bayesian analysis. All yield the same description i.e. the hydrophobic backbone remains at the uppermost surface while the PEO grafts penetrate the subphase. The PEO layer increases in thickness with increased surface concentration and graft length. In each case the rate of increase with surface concentration was initially rapid but above a critical concentration, a slower rate was observed. In this latter regime the variation of the tethered layer height scales with surface density (ơ) and degree of polymerisation of the graft (N) as, r(_s) = N(^1.06)ơ(^0.33),which agrees well with scaling and self consistent field theory of polymer brushes. The dynamic behaviour of each copolymer film spread on water has been studied using surface quasi-elastic light scattering. A resonance between the capillary and dilational waves is observed at identical surface concentrations for each copolymer film. The viscoelastic behaviour of the dilational mode is reminiscent of Kramers-Kronig relations. The phenomenon of resistive mode mixing was observed in frequency dependency studies.
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Fleet, Reda. "RAFT mediated polysaccharide copolymers." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/1025.
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Wilson, Leslie Hoipkemeier. "Bioresponse to polymeric substrates effect of surface energy, modulus, topography, and surface graft copolymers /." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011624.
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Nguyen, Sophie. "Synthesis of graft copolymers based on poly([R]-3-hydroxybutyrate) for orthopaedic surgery purposes." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85631.
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Graft copolymers using biodegradable and biocompatible bacterial poly([ R]-3-hydroxybutyrate) blocks were synthesized and tested as biomaterial candidates for orthopaedic surgery applications. Low molecular weight poly([ R]-3-hydroxyalkanoates), namely poly([R]-3-hydroxybutyrate), poly([R]-3-hydroxyvalerate), and their copolymers poly([ R]-3-hydroxybutyrate-co-[R]-3-hydroxyvalerate), were prepared by thermal degradation in the melt at 190°C. The chemical composition of the oligomers was well-defined, featuring the same repeat unit as their high molecular weight analogues, a carboxylic acid end, and an alkenyl end mostly in the trans configuration (crotonate-type). Increase in the reaction temperature, time, or [R]-3-hydroxyvalerate content decreased the molecular weight of the products. Methacrylic macromonomers of PHB were obtained by functionalization of the oligomers at the carboxyl end, and copolymerized with methyl methacrylate. Two free radical polymerization methods were employed: conventional free radical and a controlled free radical polymerization, Atom Transfer Radical Polymerization. Kinetics of the copolymerizations were studied, and the copolymerization behavior of the comonomers was shown to change with the comonomer feed composition. This would have resulted in variable graft copolymer microstructures. Graft copolymers produced by conventional free radical copolymerization were incorporated in commercial acrylic (poly(methyl methacrylate)-based) bone cement formulations. Cements with formulations containing 6.6-6.7, and 13.5 wt.-% of PMMA-graft-PHB were prepared. The morphology of the graft copolymer particles was suggested to influence the processability of the modified cement. The cements were found rather porous, with average porosities of 13.5 to 16.9%. Nevertheless compression strengths were quite similar to those found for the reference material, pure Antibiotic SimplexRTM, and met the ASTM requirements on acrylic b