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1
Lynam, Jason Martin. "Vinyl ketone and vinyl aldehyde complexes of ruthenium." Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265558.
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Yusuf, Said Abdi. "Miscibility study of poly(vinyl pyrrolidone)poly(vinyl butyral) blends." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60693.
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The miscibility of poly(vinyl pyrrolidone) PVP with copolymers of vinyl butyral and vinyl alcohol, containing 11% and 19% by weight of vinyl alcohol, has been investigated. To examine how the state of miscibility of these blends varies with the vinyl alcohol content of the copolymers, differential scanning calorimetry(DSC) and solid-state NMR methods were employed. PVP was found to form miscible blends with poly(vinyl butyral) PVB, containing 11wt% of vinyl alcohol, up to a weight ratio of 40/60(PVP/PVB11). At higher PVP loading, phase separated blends were obtained. In contrast, poly(vinyl butyral) containing 19wt% vinyl alcohol units was found to be miscible with PVP, over the entire composition range, with an estimated domain size of 2.5nm. Taken together, the results indicate the importance of the number of hydroxyl groups in achieving miscibility.
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Croot, Robert Arthur. "The characterisation and adsorption of vinyl alcohol vinyl acetate copolymers." Thesis, University of Bristol, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303767.
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Zeise, Tina. "Worte und Vinyl." Diss., lmu, 2006. http://nbn-resolving.de/urn:nbn:de:bvb:19-56250.
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Cauich-Rodriguez, Juan Valerio. "Hydrogels based on poly(vinyl alcohol-vinyl acetate) blends for biomedical applications." Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267577.
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D, Aguiar Donna-Leigh. "Surface modified cross-linked poly(vinyl alcohol)/poly(vinyl pivalate) suspension particles." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5475.
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Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2010.<br>ENGLISH ABSTRACT: In papermaking, fillers and additives are used to enhance paper properties. In this study spherical
modified poly(vinyl alcohol) (PVA) particles were prepared for use as fillers. In order to determine
the mechanism of adhesion of additives to cellulose (paper) fibres, these particles were modified to
have surface functionality, with cationic and anionic surface charges, similar to charged
polyelectrolyte additives.
Typically, retention aids used to improve the fibre–fibre and fibre–filler bonding are able to
conform to the surface of the fibres and fillers. Oppositely charged components show strong affinity
for each other, e.g. cationic polyelectrolyte groups adhere to anionic surface charges on the fibres.
The spherical PVA particles were prepared by the saponification of spherical poly(vinyl
pivalate) (PVPi) precursor particles. These PVPi particles, prepared via suspension polymerisation,
were cross-linked with a divinyl ether comonomer. The vinyl pivalate (VPi) suspension
polymerisation was successfully carried out and afforded relatively uniformly distributed PVPi
particles, with diameters of 0.5–10 mm.
The cross-linked PVPi particles were then saponified in tetrahydrofuran (THF) as swelling
solvent, to afford PVA with various degrees of saponification (DS). The spherical shape was lost and
fibrous material was obtained when uncross-linked PVPi particles were saponified. Cross-linking the
spherical PVPi particles (PVA precursor) proved innovative, and essential in maintaining the spherical
form during saponification to PVA/PVPi. By varying the saponification time periods, various DS
were obtained, as characterised by solid state NMR spectroscopy.
Surface modification of the PVA/PVPi particles was carried out with cationic and anionic
groups via the Williamson ether synthesis. Ionic modification of these rigid spherical PVA/PVPi
particles was carried out in order to study their adherence to cellulose fibres, compared to the
adherence of similarly modified starches with cellulose fibres. Fluorescent labelling of the different
modified particles was carried out using two complimentary coloured fluorescent markers.
Fluorescence imaging and scanning electron microscopy (SEM) enabled the observation of particle–
fibre and particle–particle interaction. Results indicated that the negative groups are sparse on the
cellulose fibres, and therefore particles with low functionality but which are able change shape and
conform and adhere to the surface of the cellulose fibres are required for effective adhesion.
These modified spherical PVA/PVPi particles are unique as they mirror the chemistry of
functionalised starch and cellulose particles, yet maintain their shape and have a fixed size,
measurable by SEM and transmission electron microscopy (TEM). Field-flow fractionation was also
used to characterise and measure these relatively large cross-linked and fixed diameter particles.<br>AFRIKAANSE OPSOMMING: In papierproduksie word vulstowwe en bymiddels gebruik om die eienskappe van papier te verbeter.
In hierdie studie is sferiese poli(vinielalkohol) (PVA) partikels berei vir gebruik as vulstowwe. Om
ten einde die meganisme van die bymiddelklewing aan die sellulose vesels (papier) te bepaal, is die
oppervlakke van hierdie partikels gewysig met kationiese of anioniese groepe, om 'n oppervlak
soortgelyk aan dié van funksionele poliëlektrolietbymiddels te verskaf.
Die retensiemiddels wat gebruik word om die vesel–vesel en vesel–vulstof binding te verbeter
is tipies in staat om te konformeer aan die oppervlak van die vesels en vulstowwe. Teenoorgesteldgelaaide
komponente toon 'n sterk affiniteit vir mekaar, bv. kationiese poliëlektrolietgroepe is
vasklewend aan die anioniesgelaaide oppervlakke van die vesel.
Die sferiese PVA partikels is berei deur die verseping van sferiese poli(vinielpivalaat) (PVPi)
partikels. Hierdie voorloper PVPi partikels, berei deur suspensiepolimerisasie, is gekruisbind met 'n
divinieleter ko-monomeer. Die vinielpivalaat (VPi) suspensiepolimerisasie is suksesvol uitgevoer en
relatief eenvormig verspreide sferiese PVPi partikels is berei, met deursnitte tussen 0.5–10 mm.
Die gekruisbinde PVPi partikels is daarna gesaponifiseer in tetrahidrofuraan (THF) as
oplosmiddel, om PVA met verskillende grade van verseping (DS) te berei. Die sferiese vorm raak
verlore en veselagtige materiaal is verkry wanneer PVPi partikels met geen kruisbinding verseep is.
Kruisbinding van die sferiese PVPi partikels (PVA voorloper) is voordelig en noodsaaklik om die
sferiese vorm tydens die verseping tot PVA/PVPi te behou. Deur die tydsduur van verseping te
verander, is verskeie grade van verseping verkry en bevestig deur vaste toestand KMR spektroskopie.
Oppervlakwysiging van die PVA/PVPi partikels, om kationiese en anioniese groepe aan te heg,
is uitgevoer via die Williamson etersintese. Ioniese wysiging van hierdie stram, sferiese PVA/PVPi
partikels is uitgevoer om ten einde hul klewing met sellulose vesels te bestudeer en te vergelyk met die
klewing van soortgelyk gewysigde stysels. Fluoressensie merking van die verskillende gewysigde
partikels is uitgevoer met behulp van twee komplimentêre gekleurde fluoressensie merkers.
Fluoressensie beeldvorming en SEM verskaf die waarneming van partikel–vesel en partikel–partikel
interaksie. Die resultate dui daarop dat die negatiewe groepe van die sellulose vesels skaars is, en
daarom is partikels met ‘n lae funksionaliteit, maar wat in staat is om van vorm te verander, aan te pas
en te konformeer aan die oppervlak van die sellulose vesels, nodig vir effektiewe adhesie.
Hierdie gewysigde sferiese PVA/PVPi partikels is uniek aangesien hulle die chemie van
gewysigde stysel en sellulose partikels naboots, maar steeds hul vorm behou met 'n vaste grootte;
meetbaar deur SEM en TEM. Veld-vloei-fraksionering is ook gebruik vir die karakterisering van
hierdie relatief groot, stram, gekruisbinde partikels met bepaalde deursneë.
7
Auden, Noel Geraint. "Ethylene-vinyl acetate copolymers." Thesis, Lancaster University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239046.
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Williams, S. "Vinyl substituted dienyl complexes." Thesis, University of East Anglia, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.255855.
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Buck, J. "Vinyl anions in synthesis." Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353565.
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Laot, Christelle Marie III. "Spectroscopic Characterization of Molecular Interdiffusion at a Poly(Vinyl Pyrrolidone) / Vinyl Ester Interface." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36944.
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Mechanical properties of (woven carbon fiber / vinyl ester matrix) composites can be greatly improved if the interphase between the reinforcing high-strength low-weight fiber and the thermoset resin is made more compliant. In order to improve the adhesion of the vinyl ester matrix to the carbon fiber, a thermoplastic coating such as poly(vinyl pyrrolidone) (PVP) can be used as an intermediate between the matrix and the fiber. The extent of mutual diffusion at the (sizing material / polymer matrix) interphase plays a critical role in determining the mechanical properties of the composite.
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In this research, the molecular interdiffusion across a poly(vinyl pyrrolidone))/vinyl ester monomer (PVP/VE) interface is being investigated by Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) spectroscopy. The ATR method which can be used to characterize the transport phenomena, offers several advantages, such as the ability to monitor the diffusion <I>in situ</I> or to observe chemical reactions. In order to separate the effects of the vinyl ester monomer diffusion and the crosslinking reaction, ATR experiments were carried out at temperatures below the normal curing temperature. Diffusion coefficients were determined by following variations in infrared bands as a function of time, and fitting this data to a Fickian model. The values of the diffusion coefficients calculated were consistent with values found in the literature for diffusion of small molecules in polymers. The dependence of diffusion coefficients on temperature followed the Arrhenius equation. Hydrogen bonding interactions were also characterized. The diffusion model used in this study, however, does not seem to be appropriate for the particular (PVP/VE) system. Because the glass transition temperature of the PVP changed as diffusion proceeded, one would expect that the mutual diffusion coefficient did not stay constant. In fact, it was shown that the Tg can drop by 140oC during the diffusion process. A more suitable model of the (PVP/VE) system should take into account plasticization, hydrogen bonding, and especially a concentration dependent diffusion coefficient. Further analysis is therefore needed.<br>Master of Science
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Morin, Aurélie. "Controlled radical polymerization of vinyl esters and vinyl amides : experimental and theoretical studies." Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0117/document.
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Ces travaux de thèse portent sur la polymérisation radicalaire contrôlée (PRC) des esters et amides de vinyle. L’une des possibilités de contrôle est le piégeage dynamique réversible des chaînes radicalaires croissantes (P•) par un agent de contrôle (T) formant une espèce dormante (P─T’). La concentration en radicaux dans le milieu peut alors diminuer dramatiquement de sorte que les réactions indésirables de terminaisons soient négligeables et que le contrôle de la masse molaire des polymères soit atteint avec un faible indice de dispersité. L’utilisation de complexes métalliques, pouvant s’oxider et former une liaison métal-carbone, comme agent de piégeage des radicaux est une manière de réaliser ce contrôle. La PRC est alors appelée Polymérisation Radicalaire Contrôlée par voie Organométallique (OMRP). A ce jour, plusieurs métaux de transitions ont été utilisés avec plus ou moins de succès en OMRP. Lors de cette étude, nous avons synthétisé des complexes de cuivre(I) et testé leurs performances pour l’OMRP de l’acétate de vinyle et de l’éthylène. Nous avons également utilisé des outils de chimie théorique pour mieux comprendre pourquoi le cobalt(II) acétylacétonate est, jusqu’à aujourd’hui, le meilleur agent de contrôle pour la polymérisation de l’acétate de vinyle et des amides de vinyle. Grâce à la théorie de la fonctionnelle de densité (DFT), nous avons mis en lumière le rôle crucial de la coordination sur le cobalt des groupements carbonyles des monomères étudiés<br>This thesis focus on Controlled Radical Polymerization (CRP) of vinyl esters and vinyl amides. One of the possibilities to achieve this control is a dynamic reversible trapping of the growing radical chains (P•) by a controlling agent (T) to form a dormant species (P─T’). The radical concentration in the medium can be dramatically reduced so that the unwanted terminations are disfavored and polymers with controlled molecular weights and low dispersity can be obtained. A way to achieve this control is the use of metallic complexes, which can oxidize and form a metal-carbon bond, as trapping agent in the so-called Organometallic Mediated Radical Polymerization (OMRP). So far, different transition metals have been used with gretaer or smaller success. In this study, the synthesis of copper(I) complexes and their investigation for the vinyl acetate and ethylene polymerization under OMRP conditions were performed. We also used computational chemistry as a tool to better understand why the cobalt(II) acetylacetonate (Co(acac)2) has, so far, given the best results for either vinyl acetate or vinyl amides polymerization. Thanks to Density Functional Theory (DFT), the crucial role of the monomer carbonyl group coordination to cobalt was pointed out
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Guo, Boying. "New Ring Expansion and Ring Opening Reactions of Vinyl Oxetanes and Vinyl Oxiranes." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/315543.
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Three new synthetic methods employing vinyl oxetanes as substrates are presented. In Chapter 2, a new catalytic vinyl oxetane ring expansion is described. Origins, design, reaction, and optimizations are discussed. A novel asymmetric synthesis of 3,6-dihydro-2H-pyrans using chiral counterion catalysis is presented as part of these studies. In Chapter 3, the Z-selective ring opening of vinyl oxetanes using dialkyl dithiophosphate nucleophiles is described from initial discovery, through optimizations to the application towards the synthesis of thiopyrans. These insights were then utilized to develop a similar Z-selective protocol for vinyl oxiranes. In Chapter 4, a novel method to synthesize homoallylic alcohols from 3,6-dihydro-2H-pyrans using a mild and selective C-O reduction approach is described.
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Wood, Timothy John. "An adsorption study of vinyl alcohol/vinyl acetate copolymers on polystyrene by quartz microbalance." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261278.
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Forrest, Martin J. "Characterisation of vinyl chloride oligomers." Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/27931.
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A low molecular weight fraction was obtained from a mass polymerised PVC resin by using diethyl ether Soxhlet extraction followed by either preparative gel filtration or solvent fractionation. A gas chromatography - mass spectroscopy (GC-MS) analysis of this fraction revealed that, in addition to vinyl chloride (VC) oligomers, it contained a large number of other compounds, in particular a large concentration of phthalates. By using adsorption liquid chromatography it was possible to remove the phthalates, along with other contaminants having a similar or greater polarity, from the low molecular weight PVC fraction.
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Prud'hon, Luc, and Tom Donker. "The regeneration of vinyl records." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-19122.
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This thesis analyses the factors influencing the purchase of vinyl records by the members of generation Y in Sweden. Two interviews with local stores owners as well as a survey were perfomed in this regard.
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Breen, Anthony O. "Vinyl epoxides, radicals and DNA." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336204.
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Palmer, Stuart. "Photopolymerisable poly(vinyl alcohol) systems." Thesis, University of Kent, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342158.
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Rowbottom, Martin William. "Vinyl epoxides : synthesis and reactivity." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313015.
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Lefranc, Julien. "Lithiation chemistry of vinyl ureas." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/lithiation-chemistry-of-vinyl-ureas(b559b2b8-744e-4dbe-87ee-4a5fef7d3443).html.
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The construction of tertiary alkylamines is a synthetic challenge exacerbated by the poor electrophilicity of imines. Due to the presence of this kind of building block in a large number of bioactive molecules, the development of new strategies to synthesise the quaternary carbon centre is essential. This thesis describes the work carried out on the rearrangement of lithiated vinyl ureas in order to form α-tertiary amines. The first part presents how vinyl ureas were synthesised, using the reaction between an imine and an aryl isocyanate. The development of one-pot process allows the synthesis of a range of ureas in large scale. These vinyl ureas present unusual reactivity: the electron-rich double bond can undergo syn umpolung carbolithiation followed by retentive aryl migration in order to generate highly substituted amines after cleavage of the urea. The complete mechanism is investigated to understand fully the diastereoselective pathway of the reaction. In the next part, the rearrangement of lithiated ureas is extended to the N to C vinyl transfer. Different vinyl migrating group are investigated and α-tertiary amines have been synthesised in high yields and enantiomerically pure form using this new rearrangement. The mechanistic insights of the reaction are also studied and a retentive mechanism will be identified. Finally, N to C vinyl transfer is applied toward the synthesis of Erythrina alkaloids.
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Andersson, Widing Jenny. "Vinyl, textil och textur : En kvalitativ studie om hur man kan applicera vinyl på olika textiler." Thesis, Konstfack, IBIS - Institutionen för bild- och slöjdpedagogik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-7318.
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Det finns tydliga rekommendationer för att värmeöverförande vinyl kan appliceras på polyester- eller bomullstextilier och hur lång tid med vilken temperatur man ska använda. Men det finns ingen information att hitta om hur resultatet blir om man applicerar vinylen på andra texturer än släta ytor eller värmekänsliga material. Syftet med denna studie är att undersöka vad som sker med det estetiska uttrycket och hur man kan applicera värmeöverförande vinyl på olika textila material med ett hållbart resultat. Undersökningen är uppdelad i två faser där första delen undersöker om det är möjligt att få vinylen att fästa på olika texturer och material. I detta experiment visar resultatet att det är möjligt och att rekommendationerna för vinylen bör vidgas men att det går diskutera vidare vad som är ett hållbart resultat. I den andra delen har jag tittat på de estetiska aspekterna där jag undersökt hur vinylens uttryck påverkats av textilens textur. Resultatet visar att vinylen påverkas av textilen, inte bara av dess textur utan även beroende på hur tunn eller tjock textilen är. Genom att välja olika typer av textiler kan man påverka vinylens uttryck, om den är tung/lätt, blank/matt eller slät/ojämn.
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Price, David. "Characterisation of oligomers of vinyl polymers." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/26866.
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Large scale Soxhlet extraction and fractional precipitation have been utilised to provide low molecular weight extracts from poly(vinyl chloride) (PVC), polystyrene and polyethylene. These extracts were then resolved into their constituent oligomers by high performance gel permeation chromatography and high performance liquid chromatography.
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Fairbrass, Sheila Ann. "Surface deterioration of poly(vinyl chloride)." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322083.
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Davies, Christopher Daniel. "Asymmetric synthesis utilising chiral vinyl dioxazaborocines." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322323.
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Isaure, Francoise. "Novel synthesis of branched vinyl polymers." Thesis, University of Strathclyde, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273442.
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Graham, Susan Mary. "Novel synthesis of branched vinyl polymers." Thesis, University of Strathclyde, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415302.
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Ogilvy, Norman. "Vinyl chloride precipitation polymerisation : charge effects." Thesis, University of Edinburgh, 1985. http://hdl.handle.net/1842/11229.
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Dawkins, David Anthony. "Asymmetric synthesis using chiral vinyl ethers." Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/33644.
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Using chiral alcohol precursors, a number of chiral vinyl ethers were prepared by mercuric acetate-catalysed transetherification with butyl vinyl ether. a-Lithiation of (1R)-menthyl vinyl ether was unsuccessful under a variety of conditions. (1S)-(Menthylthio)ethene was prepared from (1S)-menthanethiol but deprotonation was not possible as the thioether was found to decompose rapidly at room temperature. The deprotonation of (R)-phenethyl vinyl ether, (S)-l-(2-naphthyl)-l-ethyl vinyl ether and (S)-l-phenyl-1-butyl vinyl ether and attempted reaction with benzaldehyde yielded none of the a-alkylated adduct but a Wittig rearrangement reaction was seen. The cycloaddition reaction of benzonitrile oxide with a range of chiral vinyl ethers was investigated. The isoxazoline product was isolated as a mixture of two diastereoisomers after flash column chromatography. In most cases the diastereoisomer ratio neared 1:1, but (S)-l-(2-naphthyl)-l-ethyl vinyl ether and 1-phenyl-1-butyl vinyl ether gave a single diastereoisomer of the isoxazoline product, after chromatography, with a variety of nitrile oxides. Conditions have been developed for the removal of the chiral auxiliary but as yet only achiral isoxazolines have been obtained by this method. Attempts at ring deprotonation/alkylation and also the addition of a nucleophile or radical to the isoxazoline C=N bond were hindered by the instability of the isoxazoline adducts. A chiral vinyl pyrrolidinone was also prepared and found to undergo an asymmetric cycloaddition reaction with benzonitrile oxide to yield a single diastereoisomer of the isoxazoline product. The equivalent acrylamide was synthesised and, although this gave a 1:1 mixture of diastereoisomers with both benzonitrile oxide and 2,2-dimethylpropanenitrile oxide, these diastereoisomers could be separated. Removal of the chiral auxiliary yielded hydroxyisoxazolines with an enantiomeric excess of 90-94%. Attempts to investigate the extent of any asymmetric induction in the cycloaddition of nitrile oxides to chiral vinyl sulphoxides were hampered by the instability of the isoxazoline product, which underwent an immediate syn-elimination. In an effort to determine the potential of chloromethyl-(1R)-menthyl ether as a chiral OH protecting group, a series of (1R)-menthoxymethyl ethers were prepared from a variety of racemic and homochiral alcohols. Conditions for deprotection were developed which did not lead to the racemisation of homochiral alcohols. The usefulness of the (1R)-menthoxymethyl ether group as a simple means of measuring enantiomeric excess was demonstrated in a silicon-directed diene synthesis.
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Hong, Jin-Who. "Spectroscopic studies of poly(vinyl fluoride)." Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055351497.
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Dorobantu, Ioana-Miruna. "Vinyl chloride polymerization in microdroplet reactor." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0037/document.
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La polymérisation du chlorure de vinyle est une réaction très fréquente dans l’industrie des polymères, conduisant à l’obtention d’un matériau plastique très commun, connu sous le nom de PVC (polychlorure de vinyle). Ses applications concernent principalement l’industrie des constructions néanmoins d’autres domaines sont également touchés. La complexité de ce procédé de polymérisation est due à la nature toxique du monomère, à la maitrise du transfert de chaleur ou au maintien de l’agitation. Le control de ces variables de procédé influence de manière directe les caractéristiques finales du produit. Même si la polymérisation en suspension du chlorure de vinyle a été largement étudiée dans des réacteurs de type batch, il y a un manque de données au niveau de la cinétique et de la physicochimie d’une goutte de monomère pendant la réaction. L’objectif de ces travaux est de proposer un dispositif microstructuré permettant d’obtenir des gouttes monodisperses ayant un diamètre de 200 µm environ, chacune étant considérée comme un réacteur de polymérisation. Une fois identifiés les verrous liés au système eau/chlorure de vinyle en microréacteur, la réaction de polymérisation a été décrite de manière qualitative par visualisation des gouttes/grains de polymère. Des mesures Raman non-invasives en temps réel ont été réalisées sur une goutte immobile de chlorure de vinyle, cela permettant d’accéder aux valeurs des constantes cinétiques. Un modèle théorique en bon accord avec les résultats expérimentaux a été proposé afin de simuler le degré de conversion de la réaction. Les caractéristiques morphologiques des grains de PVC obtenus en microréacteur présentent des particularités intéressantes en termes d’agglomération des particules primaires ou porosité<br>Vinyl chloride suspension polymerization is a common reaction in polymer industry allowing to obtain one of the world wide most used plastics, known as PVC (polyvinyl chloride). Its applications involve mostly the construction industry but other domains are also concerned. This polymerization process is highly complex due to the toxic nature of the monomer, the good manage of heat transfer and agitation. The control of these process variables directly impacts the characteristics of the final product. Even though the suspension polymerization of vinyl chloride has been extensively studied in batch reactors, there is a lack of data regarding the kinetics or the physicochemistry of a single monomer droplet during the reactions. The aim of this present work is to propose a microstructured device which enables obtaining monodisperse droplets within 200 µm in diameter, each one being considered as a polymerization reactor. After a good acknowledgement of the vinyl chloride/water system in microchannel the polymerization reaction was qualitatively described by means of droplet/polymer grain visualization. Real-time non-invasive Raman measurement has been performed on stationary vinyl chloride monomer droplets and has provided values of kinetic constants. A theoretical model was proposed, simulating the reaction conversion in good agreement with the experimental values. The morphologic characteristics of the PVC grains obtained in microreactor presented interesting features in terms of primary particle agglomeration or porosity
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De, Bruyn Hank. "The Emulsion Polymerization of Vinyl Acetate." Thesis, The University of Sydney, 1999. http://hdl.handle.net/2123/381.
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Abstract This work investigates the kinetics of the emulsion polymerization of vinyl acetate. Several aspects of this system have been clarified, including the induced decomposition of persulfate, retardation by oxygen and entry by, and analysis of, the aqueous phase oligomeric radicals. It has been shown that the retardation period observed in the emulsion polymerization of VAc can be explained by the effect of traces of oxygen (< 10-6 M) on the entry efficiency of the initiator-derived aqueous-phase oligomeric radicals. Comparison of rates of polymerization in V and persulfate -initiated polymerizations together with electrospray mass spectrometry of aqueous phase oligomers, has shown that the mechanism for the induced decomposition of persulfate by vinyl acetate is chain transfer to initiator from aqueous-phase oligomeric radicals. A value has been determined for the rate coefficient for transfer to initiator, by fitting literature data to a model based on this mechanism. The reported independence of the rate of polymerization from the monomer concentration in the emulsion polymerization of vinyl acetate has been investigated. Possible explanations for this behaviour have been proposed and tested in this work, by measuring radical-loss rates directly with y-relaxation techniques. Although the Y relaxations were found to be affected by experimental artefacts, it has been demonstrated that rapid exit is not responsible for the high radical-loss rates in this system. The major artefact identified in the y relaxations was the significant effect of relatively small exotherms on relaxation behaviour, Methodologies were developed for correcting affected data and for avoiding exotherms under certain conditions. Arrhenius parameters were determined for the rate coefficient for chain transfer to monomer using the In^M method, which utilises the whole MWD. This section of the work is incomplete, for reasons detailed in chapter 5. However, as a preliminary indication it was found that the frequency factor was 106.38 M-1 s-1 and the activation energy was 38.8 kJ mol-1.
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De, Bruyn Hank. "The Emulsion Polymerization of Vinyl Acetate." University of Sydney, Chemistry, 1999. http://hdl.handle.net/2123/381.
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Abstract This work investigates the kinetics of the emulsion polymerization of vinyl acetate. Several aspects of this system have been clarified, including the induced decomposition of persulfate, retardation by oxygen and entry by, and analysis of, the aqueous phase oligomeric radicals. It has been shown that the retardation period observed in the emulsion polymerization of VAc can be explained by the effect of traces of oxygen (< 10-6 M) on the entry efficiency of the initiator-derived aqueous-phase oligomeric radicals. Comparison of rates of polymerization in V and persulfate -initiated polymerizations together with electrospray mass spectrometry of aqueous phase oligomers, has shown that the mechanism for the induced decomposition of persulfate by vinyl acetate is chain transfer to initiator from aqueous-phase oligomeric radicals. A value has been determined for the rate coefficient for transfer to initiator, by fitting literature data to a model based on this mechanism. The reported independence of the rate of polymerization from the monomer concentration in the emulsion polymerization of vinyl acetate has been investigated. Possible explanations for this behaviour have been proposed and tested in this work, by measuring radical-loss rates directly with y-relaxation techniques. Although the Y relaxations were found to be affected by experimental artefacts, it has been demonstrated that rapid exit is not responsible for the high radical-loss rates in this system. The major artefact identified in the y relaxations was the significant effect of relatively small exotherms on relaxation behaviour, Methodologies were developed for correcting affected data and for avoiding exotherms under certain conditions. Arrhenius parameters were determined for the rate coefficient for chain transfer to monomer using the In^M method, which utilises the whole MWD. This section of the work is incomplete, for reasons detailed in chapter 5. However, as a preliminary indication it was found that the frequency factor was 106.38 M-1 s-1 and the activation energy was 38.8 kJ mol-1.
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Gestoso, Souto Patricia. "Orientation study of poly(vinyl phenol)/poly(vinyl methyl ether) blends by infrared dichroism and molecular dynamics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ65420.pdf.
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Kim, Young-Min MacGregor John Frederick. "Photopolymerization of cycloaliphatic epoxide and vinyl ether /." *McMaster only, 2005.
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Walmsley, P. G. S. "Surface characteristics of vinyl polysiloxane impression materials /." Title page, summary and contents only, 1991. http://web4.library.adelaide.edu.au/theses/09DM/09dmw216.pdf.
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Vessey, Jonathan Dennis. "Hydride, alkene and vinyl complexes of ruthenium." Thesis, University of York, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.483971.
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Clough, Norman E. "Thermodynamics of ethylene-vinyl acetate copolymer blends." Thesis, Durham University, 1994. http://etheses.dur.ac.uk/5489/.
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The purpose of this study was to characterise the miscibility of several poly(ethylene-co-vinyl acetate), EVA, based polymer blends. EVA has many industrial applications and is often present as one of several polymeric components. Consequently, there is considerable interest in the thermodynamics of these blend systems. The thermodynamics of these blends was studied using several techniques: differential scanning calorimetry; phase contrast optical microscopy; small angle neutron scattering and wide angle X-ray scattering. Characterisation was also to include assessing the relative enthalpic and entropic thermodynamic contributions to the Rory-Huggins interaction parameter (%) of these blends. To determine the enthalpic interaction parameter, a "mixing calorimeter" was designed and constructed to measure accurately the "heat of mixing" values on blending these polymers. Free energy interaction parameters were determined from melting point depression and small angle neutron scattering measurements. In all the blends studied, the heat of mixing was endothermic and consequently, the enthalpic interaction parameters were positive i.e. unfavourable to miscibility. Miscibility in these blends can therefore only be achieved by a dominant entropic contribution, favourable to miscibility. Using phase contrast optical microscopy, both miscible and immiscible phase behaviour was observed in this series of blends. This shows good agreement with predictions of miscibility from heat of mixing, melting point and small angle neutron scattering measurements, based on the classical Flory-Huggins lattice theory. Wide angle X-ray scattering and differential scanning calorimetry results have associated miscible blends with crystallisation effects between the blend components. Small angle neutron scattering has been used to determine the concentration and temperature dependence of interaction parameters in a miscible blend. From these values the upper critical solution temperature (UCST) of the blend was predicted. The enthalpic contributions to these interaction parameters show good agreement with experimental values determined from heat of mixing measurements. It was concluded that the classical Flory-Huggins lattice theory (despite its many well documented Limitations) appears to be particularly suited to the thermodynamic characterisation of miscibility in these polymer blends.
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Grainger, Richard Sheridan. "Cycloaddition reactions of C2-symmetric vinyl sulfoxides." Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387754.
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Sham, C. K. "Studies of poly (vinyl chloride)/polyacrylate blends." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37850.
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Weidner, Craig. "Yield improvement efforts in vinyl siding production." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/28167.
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Tongcher, Oychai. "Novel routes to stereoregular poly(vinyl acetate)." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620688.
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House, Stewart Nicholas. "Studies on chiral allenyl and vinyl anions." Thesis, University of Leicester, 1989. http://hdl.handle.net/2381/33738.
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Cha, Won-ill. "Physicochemical studies on poly (vinyl alcohol) hydrogels." Kyoto University, 1994. http://hdl.handle.net/2433/168897.
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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである<br>Kyoto University (京都大学)<br>0048<br>新制・論文博士<br>博士(工学)<br>乙第8528号<br>論工博第2849号<br>新制||工||958(附属図書館)<br>UT51-94-J257<br>(主査)教授 筏 義人, 教授 升田 利史郎, 教授 池内 健<br>学位規則第4条第2項該当
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Roy, Monali. "Synthesis and characterisation of vinyl block copolymers." Thesis, Aston University, 1995. http://publications.aston.ac.uk/9678/.
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A study has been made of the anionic polymerisation of methyl methacrylate using butyllithium and polystyryl lithium as initiators and the effects of lithium chloride and aluminium alkyls on the molecular weight and molecular weight distributions. Diblock copolymers of styrene-b-methyl methacrylate were synthesised at -78oC in THF in the presence of lithium chloride, and at ambient temperatures in toluene in the presence of aluminium alkyls. Studies in the presence of lithium chloride showed that the polymerisation was difficult to control; there was no conclusive evidence of a living system and the polydispersity indices were between 1.5 and 3. However, using relatively apolar solvents, in the presence of aluminium alkyls, homopolymerisation of methyl methacrylate showed characteristics of a living polymerisation. An investigation of the effects of the structures of the lithium and aluminium alkyls on the efficiency of initiation showed that a t-butyllithium/triisobutylaluminium initiating system exhibited an efficiency of 80%, compared with lower efficiencies (typically 30%) for systems based on butyllithium/triethylaluminium. The polydispersity index was found to decrease from ˜2.2 to ˜1.5 when butyllithium was replaced by t-butyllithium. The efficiency of the initiator was found to be solely dependent on the size of the alkyl group of the aluminium component, whereas the polydispersity index was found to be solely dependent on the size of the alkyl group on the lithium component. The aluminium alkyl is thought to be co-ordinated to the ester carbonyl groups of both the monomer and polymer. There is a critical degree of polymerisation, at which point the rate of polymerisation decreases, which probably relates to a change in structure of the active chain end.
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Shah, Apoorva P. "Moisture diffusion through vinyl ester/clay nanocomposites." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2189.
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Thesis (M.S.)--West Virginia University, 2001.<br>Title from document title page. Document formatted into pages; contains xii, 147 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 97-100).
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Guo, Qin. "Synthesis and oxidation of vinyl stannyl sulfides." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/187512.
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The alpha-tin effect in which a C-Sn bond adjacent to a thioether interacts with the sulfur 3p lone pair orbital was found in saturated thioethers and results in a lowering of the oxidation potentials of these compounds. From the electrochemical oxidation potentials found in this study the alpha-tin effect is also present in vinyl sulfides. The geometry of the compounds is the key factor in determining the overlap of the sulfur 3p lone pair orbital with the filled C-Sn bond which results in decreasing oxidation potentials. The change in oxidation potentials of disubstituted stannylated or silylated compounds, 3 to 8, is small (compared with phenyl vinyl sulfur the change is about 0.18 to 0.24 V). The change in oxidation potential increase, when the overlap of the sulfur 3p lone pair orbital with the filled C-Sn bond increases such as in compounds 13 to 21 (in these cases the oxidation potentials compared to phenyl vinyl sulfur change by 0.24 to 0.57 V). The bistin effect does not seem to be an important factor in decreasing the oxidation potential due to a possible interaction between the sulfur and the tin cis to the sulfur. Since most of the compounds studied have a phenyl group attached to sulfur, rotation about the C-S bond to the phenyl ring is expected to affect the oxidation potential, but this does not appear to be a crucial factor in the vinyl sulfide system. The solved x-ray structures provide important information in understanding the relationship between the conformation and overlap between the sulfur 3p lone pair orbital and the filled C-Sn bond.
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Zaikov, Vadim Guennadievich. "A study of poly(vinyl chloride) microstructure." W&M ScholarWorks, 1997. https://scholarworks.wm.edu/etd/1539623916.
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High-field {dollar}\sp{lcub}13{rcub}{dollar}C and {dollar}\sp1{dollar}H NMR spectroscopies were used to investigate some unusual features of the molecular microstructure of poly(vinyl chloride) (PVC).;Several model monochloroalkenes were synthesized in order to determine {dollar}\sp{lcub}13{rcub}{dollar}C shift increments for the replacement of H by Cl at positions that are near an isolated internal double bond. These increments then were used to predict the {dollar}\sp{lcub}13{rcub}{dollar}C shifts of the internal allylic chloride structure in PVC. The predictions were not satisfactory, because, as expected, the increments were not additive.;It was shown that during conventional VC polymerization, the chloroallylic chain end (-CH{dollar}\sb2{dollar}CH=CHCH{dollar}\sb2{dollar}Cl) does not copolymerize with the monomer and is not destroyed by a mechanism involving allylic rearrangement, macroradical addition, and chlorine-atom {dollar}\beta{dollar}-scission to produce a -CHClCH{dollar}\sb2{dollar}CH=CHCH{dollar}\sb2{dollar}CHCl- structure. Nevertheless, that mechanism was found to operate during the preparation of a special type of PVC (made at 0{dollar}\sp\circ{dollar}C with (t-Bu){dollar}\sb2{dollar}Mg initiation) which contained the rearranged chain end, -CH{dollar}\sb2{dollar}-CHClCH=CH{dollar}\sb2,{dollar} at an abnormally high concentration.;During the preparation of PVC under subsaturation VC pressures, small amounts of a 1,3-di(2-chloroethyl) branch structure were found to be formed by a "double backbiting" mechanism involving two intramolecular H abstractions in succession. The presence of this structural defect was established by the 125.77-MHz {dollar}\sp{lcub}13{rcub}{dollar}C NMR spectra of reductively dechlorinated PVC specimens. at 55-80{dollar}\sp\circ{dollar}C, the two backbites leading to the defect differ substantially in relative rate, in that the backbiting:addition rate ratio is larger for the second backbite by a factor of 15-16, irrespective of temperature. No evidence was obtained for the presence of the 2-ethyl-n-hexyl branch structure that would have resulted from double backbiting by an alternative route. These findings were confirmed by spectral comparisons with the {dollar}\sp{lcub}13{rcub}{dollar}C shifts of two separately synthesized models, 9,11-diethylnonadecane and 9-(2-ethyl-n-hexyl)heptadecane.;Polymerizations of VC were performed in the presence of two potential transfer agents, trans-1-chloro-2-hexene and trans-1,5-dichloro-2-pentene. Preliminary examination of the resulting polymers by high-field NMR provided evidence for the destruction of the -CH{dollar}\sb2{dollar}CH=CHCH{dollar}\sb2{dollar}Cl chain end, during polymerization, by a mechanism involving H abstraction to form the -CH{dollar}\sb2{dollar}CH=CHC{dollar}\sp{lcub}\cdot{rcub}{dollar}HCl radical, followed by the addition of that species to VC in order to give the -CH{dollar}\sb2{dollar}CH=CHCHClCH{dollar}\sb2{dollar}- structure.
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Ohgi, Hiroyuki. "Studies on Synthesis and Physical Properties of Highly Isotactic Poly(vinyl alcohol) Derived from Poly(tert-butyl vinyl ether)." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/57290.
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Wang, Chao. "Oxydation catalytique des composés organiques volatils à l’aide de catalyseurs de type oxyde." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1332.
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Dans ce travail de recherche, des oxydes mixtes dopés par des métaux nobles ont été préparés et mis en œuvre dans la réaction d'oxydation catalytique du chlorure de vinyle (VC). Les catalyseurs d'oxyde composite de Co-Ce ont été préparés par des procédés sol-gel et testés pour l'activité d'oxydation du VC. L'analyse XPS a certifié que l'introduction de Ce favorisait la présence d'espèces de Co2 + et de Ce3 +, ce qui modifie l'environnement de coordination du réseau d'oxygène et génère plus de vacations d'oxygène. Les oxydes de cobalt modifiés par Ru ont été préparés et étudiés pour l'oxydation du VC. L'analyse XPS montre que le Ru4 + et le Co2 + modifie la concentration des espèces oxygènes sur la surface. Une proportion relative élevée de Co2+ et de Ru4+ perturbe également les lacunes en oxygène. Cela impacte l'activité catalytique et diminue la quantité de sous-produits chlorés. Des mousses cellulaires mésostructurées de phosphate de cobalt-SiO2 (CoPO-MCFs) ont été synthétisées avec succès par la méthode de croissance in situ. Les analyses XPS confirment une augmentation d'espèces d'oxygène de surface pour ce système catalytique. L'énergie apparente d'activation confirme cette tendance. L'influence de la morphologie des particules de Co3O4, sur l'activité catalytique du méthyl benzène et du chlorure de vinyle a été étudiée. Le Co3O4 cubique a montré une meilleure activité et une meilleure stabilité que celle de Co3O4 sphérique. La structure cubique, avec Co2 + exposée à la surface, est le site actif de l'oxydation<br>In this research works, composite oxides, noble metal supported oxides and noble supported MCFs were prepared, and their catalytic performances were investigated for the catalytic oxidation of vinyl chloride (VC). The Co-Ce composite oxide catalysts were prepared by citrate sol-gel methods, and tested for the activity of VC oxidation. The catalyst with high performance is the molar ratio of Co/Ce=7:3. The XPS analyse certified that the Ce introduction favored the presence of Co2+ and Ce3+ species, which changed the coordination environment of the oxygen lattice and generated more oxygen vacancies. At last, this catalyst exhibited a good performance and stability during 110 h of time on stream at 300 oC. Ru-modified cobalt oxides were prepared and studied for the VC oxidation. The XPS analyse certified that the Ru4+ will be in synergy with Co2+ concentration and this would also change the chemical coordination of oxygen on the surface. High relative proportion of Co2+ and Ru4+ will also devote to oxygen defects or vacancies. This would increased the catalytic activity and decrease the amount of chlorinated by-products.A novel heterostructured material, cobalt phosphate-SiO2 mesostructured cellular foams (CoPO-MCFs), was successfully synthesized by the in-situ growth method. The XPS confirmed a higher amount of surface oxygen species. The activation energy calculated from Arrhenius plots showed a lower value for VC oxidation. The influence of Co3O4 morphology, including cube and sphere, on catalytic activity of methylbenzene and vinyl chloride was studied. The Co3O4 cube had shown better activity and stability than that of the Co3O4 sphere. The cube structure, with Co2+ exposed on the surface, acted as the active site of the oxidation
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Semenzim, Vinícius Ladeia [UNESP]. "Pesquisa e desenvolvimento de microesferas de poli(vinil álcool) com alta cristalinidade para utilização em embolização e quimioembolização." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/87529.
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000696944.pdf: 398566 bytes, checksum: 3105a99c9e8591292c70a0dc96958d0a (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Partículas poliméricas com tamanho e morfologia controlados e propriedades físico-químicas adequadas são amplamente utilizadas em várias aplicações biomédicas, especialmente em embolização, uma técnica cirúrgica minimamente invasiva utilizada em tratamentos de diversas doenças vasculares e quimioembolização, que associa a embolização e a quimioterapia. Ela é realizada com uso de materiais denominados agentes embólicos, sendo as partículas de poli(vinil álcool) (PVA) amplamente utilizadas por apresentarem um alto grau de desempenho. As partículas de PVA estão disponíveis no mercado nas morfologias esféricas e floculares, sendo as esféricas as que apresentam menores riscos para o procedimento. Dessa forma, o presente trabalho teve como objetivo sintetizar e caracterizar microesferas de PVA para serem utilizadas em embolização e quimioembolização. Juntamente com a equipe de pesquisadores da empresa Braile Biomédica, a intenção é desenvolver um produto que ainda não é fabricado pela indústria nacional para ser comercializado a menores custos. Materiais e Métodos: As microesferas de poli(vinil álcool) (PVA) foram sintetizadas pelo método de polimerização em suspensão, seguida de hidrólise alcalina (ou saponificação). Na etapa de saponificação, diferentes concentrações de NaOH foram utilizadas. As amostras sintetizadas foram caracterizadas por Microescopia Eletrônica de Varredura (MEV), Difração de Raios-X (DRX), Calorimetria Diferencial de Varredura (DSC), Ressonância Magnética Nuclear de 13 C - cross polarization / magic angle spinning ( 13 C RMN CP/MAS) e Potencial Zeta (ζ). Resultados: A análise de MEV indicou que foram obtidas partículas esféricas. Os dados complementares de DRX, DSC e 13 C RMN CP/MAS indicam que à medida que se aumenta a concentração...<br>Polymeric particles with size and morphology controlled and appropriate physicochemical properties are widely used in several biomedical applications, especially in embolization, a minimally invasive procedure routinely used in treatments of some vascular diseases, and chemoembolization, which combines embolization and chemotherapy. It is performed using materials called embolic agents, being poly(vinyl alcohol) (PVA) particles often used because its high performance. These particles are commercially available in spherical and flocculate morphologies, however spherical particles present lower risks than flocculates ones during the procedure. Thus, this study proposes to develop and improve spherical PVA particles to be used in embolization and chemoembolization. The development are being conducted by the researchers group from Braile Biomédica, the goal is to develop a product that is not yet produced in the national industry, commercializing it at lower costs. Materials and Methods: PVA microspheres were synthesized by suspension polymerization method, followed by alkali hydrolysis (or saponification). In the saponification step, different concentrations of NaOH were used. The samples synthesized were characterized by Scanning Electronic Microscopy (SEM), X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), 13 C Nuclear Magnetic Resonance - cross polarization / magic angle spinning ( 13 C CP/MAS NMR) and Zeta Potential (ζ). Results: SEM analysis indicated that spherical particles were obtained. The complementary data of XRD, DSC and 13 C CP/MAS NMR indicate that the use of high NaOH concentrations (in the saponification process) determines reordering in the lateral chains of the polymer, which causes an increase of material’s crystallinity. Zeta Potential (ζ) data of the samples indicated that, in an... (Complete abstract click electronic access below)
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Estur, Jean-François. "Procédé de transformation directe du furfural en vinyl-2furanne." Toulouse, INPT, 1989. http://www.theses.fr/1989INPT013G.
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Apres une mise au point bibliographique sur le vinyl-2 furanne et sa synthese, la production de ce monomere en milieu solide-liquide faiblement hydrate a partir du furfural est realisee en une seule etape. L'etude s'appuie sur la methodologie de la recherche experimentale. Elle a permis de conduire la synthese du stade laboratoire jusqu'a un prepilote de 20 litres tout en conservant sa selectivite et son haut rendement. Une estimation de la cinetique ainsi que de l'enthalpie de la reaction a ete effectuee. L'etude de la separation des constituants du milieu reactionnel par distillation et precipitation permet de proposer un procede de synthese industrielle