Dissertations / Theses on the topic 'Styrene'
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1
Lewis, M. N. "Styrene-ethylene/butylene-styrene layered silicate nanocomposites." Thesis, Queen's University Belfast, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432525.
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Ba, Housseinou. "Manufacturing of metal-free carbon-based catalysts for styrene production." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF026/document.
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Le styrène (ST) est l'un des monomères aromatiques insaturés les plus importants dans l'industrie pétrochimique moderne. Le procédé de déshydrogénation (DH) de l'éthylbenzène (EB) en ST, représentant actuellement 90% de la production de ST, nécessite l'utilisation de catalyseurs hautement actifs et stables, et permettant un grand transfert de masse. Dans ce travail, nous avons développé de nouveaux matériaux sans métaux à base de carbone, utilisant les nanodiamants (NDs) comme phase active pour la production de ST. Les NDs ont été déposés sur différents supports 2D et 3D à base de carbure de silicium et de carbone, permettant d'améliorer leur dispersion, et conduisant ainsi à un catalyseur exempt de métal très stable avec des performances en DH élevées. Nous avons également réussi à synthétiser des matériaux carbonés dopés à l'azote (N@C) présentant une activité élevée et stable en DH comparée à celle obtenue sur NDs. Cette phase active N@C a été obtenue à partir de produits alimentaires (le D-glucose, l'acide citrique et le carbonate d'ammonium) par un procédé facile à mettre en œuvre, et peut aussi très bien être déposée sur d'autres supports macroscopiquesStyrene (ST) is one of the most important unsaturated aromatic monomers in modern petrochemical industry. The catalytic dehydrogenation reaction (DH) of ethylbenzene (EB) into styrene, which accounts for 90% of the ST production, demands highly activated and stabilized catalysts, as well as easily handing and efficient mass diffusion. In this work, we developed novel metal-free carbon-based materials using nanodiamonds (NDs) as an active phase for potential industrial catalysts for the direct dehydrogenation route to produce ST. The NDs were successfully immobilized on different 2D and 3D carbon-based and silicon carbide supports which could help to improve their dispersion, leading to metal-free catalyst with high catalytic performance and stability. We have also succeeded in synthesizing nitrogen-doped carbon materials (N@C) displaying a high and stable dehydrogenation activity for the ST production in place of NDs. These active N@C catalysts were produced from food processing materials, i.e. D-glucose, citric acid and ammonium carbonate, and could be also easily dressed on macroscopic supports by a facile and scalable method
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Wu, Jiawei. "Study on Epoxidized Poly (Styrene-butadiene-styrene) Modified Epoxy Resins." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1571671436341218.
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Kohn, Judith. "Assessment of the toxicity of styrene, styrene oxide, and styrene glycol in primary cultures of motor and sensory neurons." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68190.
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Chronic occupational exposure to styrene is associated with a number of adverse effects on the nervous system, including sensory neuropathy and neurophysiological alterations. In order to test styrene for neurotoxic potential and investigate its mechanism of action, primary co-cultures of murine spinal cord-dorsal root ganglia (DRG)-skeletal muscle were used in a simple in vitro neurotoxicity screen. The neurotoxicity of styrene and its major metabolites, styrene oxide and styrene glycol was evaluated after both short and long-term exposure. Endpoints used to characterize neurotoxicity were both morphological and neurophysiological, and included: (1) chromatolysis, (2) axonopathy, and (3) interference with action potential generation. The major findings of this study were: (1) styrene and oxide were acutely cytotoxic to all cell types at concentrations in excess of 2.0 mM and 0.2 mM respectively. (2) There was no evidence of neurotoxicity attributable to styrene or its metabolites, with the exception of a slight chromatolytic effect induced by 0.2 mM styrene oxide in DRG neurons after long-term exposure. It is therefore possible that cytotoxic mechanisms rather than effects on neuron specific processes, underlie styrene's damage to cells of the nervous system. (3) Surprisingly, dimethyl sulfoxide (DMSO), a common in vitro solubility vehicle, was neurotoxic after long-term exposure, producing both chromatolysis and axonopathy. This study, therefore also established the upper limit of DMSO recommended for use as a solubility vehicle in long-term in vitro tests.
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Shen, Naifu. "Macromolecular Engineering and Additive Manufacturing of Poly(styrene-b-isobutylene-b-styrene) (SIBS)." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1626879104460335.
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Clas, Sophie-Dorothée. "Synthesis and bulk physical properties of styrene-4-hydroxystyrene and styrene-4-hydroxymethylstyrene ionomers." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=71957.
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Polystyrene-co-4-hydroxystyrene ionomers (3.0-22 mol %) were synthesized via neutralization of demethylated polystyrene-co-4-methoxystyrene. The polystyrene-co-4-hydroxymethylstyrene ionomers (2.5-19.4 mol %) were prepared from the partial chloromethylation of polystyrene, followed by esterification, saponification, and finally neutralization. The physical properties of the ionomers as well as their nonionic precursors were studied by calorimetry, torsion pendulum and small-angle X-ray scattering (SAXS). Stress relaxation studies of the ionomers were also done. While evidence for ion aggregation was obtained for the styrene-4-hydroxystyrene ionomers from SAXS and torsion pendulum studies, no firm evidence was obtained for the styrene-4-hydroxymethylstyrene ionomers. Stress relaxation studies on both systems, however, showed failure of time-temperature superposition at high ion contents, indicating that these systems are both thermorheologically complex. The glass transition temperature of the matrix, the size of the ionic aggregates and the strengths of the ionic interactions within these large aggregates were related to the type and position of the ionic group.
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Kindström, Patricia. "Working Towards the Heterologous Expression of Styrene Monooxygenases for Styrene Epoxidation and Reaction Cascades." Thesis, Uppsala universitet, Institutionen för kemi - BMC, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-368314.
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Previously, styrene oxide has been used as starting material in the reaction cascade for obtaining 2-hydroxyacetophenone. If the path could be extended to instead start with styrene as substrate, it would be an advantage financially. The aim of this degree project was to produce two monooxygenase components needed for the epoxidation of styrene. The coding sequence for styrene monooxygenase component StyA had in an earlier project been inserted in a plasmid which in this project was used for inserting the gene coding for the styrene monooxygenase component StyB. The transformation of the ligated plasmid became problematic and did not result in the expected outcome. When doing an transformation directly on the ligation mixture, the result of the experiment was successful. Consequently, the problem was likely due to the poor condition of the cells used.
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Laur, Eva. "Rare-earth metallocene complexes for syndioselective styrene (co)polymerization." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S168.
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Les travaux présentés dans ce manuscrit portent sur la (co)polymérisation syndiosélective du styrène catalysée par des complexes de métaux du Groupe 3. La première partie est consacrée à l’optimisation des performances catalytiques de systèmes neutres de type {Cp/Flu}. Une série de précurseurs ansa-lanthanidocènes a été synthétisée et testée en homopolymérisation du styrène et en copolymérisation styrène-éthylène. Il a été montré que la nature de la substitution du motif fluorényle, la nature du centre métallique ainsi que les conditions de polymérisation ont une influence significative sur la productivité des catalyseurs. En conditions optimisées, des productivités maximales de 4,500 kg(sPS)·mol⁻¹·h⁻¹ et 5,430 kg(sPSE)·mol⁻¹·h⁻¹ ont été obtenues, démontrant la robustesse sans précédent de ces systèmes catalytiques en conditions extrêmes (Tpolym jusqu’à 140 °C et charge en monomère > 100,000). De nouveaux co- et terpolymères styrène-myrcène et styrène-myrcène-éthylène contenant des séquences de polystyrène syndiotactique ont également été synthétisés. La deuxième partie de ce travail porte sur le développement de nouveaux catalyseurs cationiques. Très peu des composés ciblés ont été isolés de par la réactivité déroutante entre les pro-ligands et les précurseurs ou la faible stabilité thermodynamique des produits. De plus, les productivités catalytiques des composés qui ont été isolés se sont avérées assez faiblesThe work presented in this thesis manuscript focuses on the syndioselective (co)polymerization of styrene catalyzed by Group 3 catalysts. The first part is dedicated to the optimization of the catalytic performances of neutral {Cp/Flu} systems. A series of new allyl ansa-lanthanidocenes was synthesized and explored in styrene and styrene-ethylene (co)polymerizations. It is shown that the substitution of the fluorenyl moiety as well as the nature of the metal center and the polymerization conditions exert a strong influence on the catalyst productivity. Under optimized conditions, maximum productivities of up to 4,500 kg(sPS)·mol⁻¹·h⁻¹ and 5,430 kg(sPSE)·mol⁻¹·h⁻¹ were achieved, highlighting the unprecedented robustness of those catalytic systems under drastic conditions (Tpolym up to 140 °C and monomer : catalyst ratios > 100,000). New styrene-myrcene(-ethylene) co- and terpolymers containing syndiotactic polystyrene sequences were also synthesized. The second part of the study was focused on the development of new cationic catalysts. Only a short series of compounds was successfully isolated among the targeted ones, because of unclear reactivity of pro-ligands and metal precursors and/or low thermodynamic stability of the products. The new isolated compounds were also used in styrene homopolymerization affording unexpectedly poor performances
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Yanguas, Adriana Barcelona. "Degredation and stabilisation of styrene-butadiene (S-B-S) block copolymer with high styrene content." Thesis, Manchester Metropolitan University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412904.
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Overton, Bob James. "The effects of microstructure and styrene content on the rheological properties of styrene-butadiene random copolymers." Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/10196.
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Prasman, Elisabeth. "Morophology and mechanical behavior of oriented blends of styrene-isoprene-styrene triblock copolymer and mineral oil." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43444.
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Maron, Elizabeth Sara. "Fluorinated styrene polymers for optical waveguides." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32281.
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A series of fluorinated copolymers were prepared and used to fabricate optical waveguides by photolithography. Reproducible syntheses were established for a buffer material, 4-fluoro-styrene-co-pentafluoro-styrene-co-[4-styren-4'-yl-2,3,5,6-tetrafluorophenylether] (bufTxx), and guiding material, Styrene-co-penta-fluorostyrene-co-[4-styren-4'-yl-2,3,5,6-tetrafluorophenyl-ether] (terTxx), as well as their precursors. The polymers were characterized by attenuated total reflection Fourrier transform infrared spectroscopy (ATR FT-IR), gel permeation chromatography (GPC), proton nuclear magnetic resonance spectroscopy (1H NMR), and thermal analyses. Freestanding waveguide structures and multilayer buried waveguide devices were prepared on silicon substrates. The guiding polymer behaved as a negative resist, facilitating photoinitiated lithographic printing. These structures were investigated by optical microscopy, field-emission gun scanning electron microscopy (FEG SEM) and prism coupling analysis. A 632 nm HeNe laser was successfully end-coupled to printed waveguide structures from an optical fiber.Une série de copolymères fluorés a été préparée et employée pour fabriquer des guides d'ondes optiques par photolithographie. Des synthèses reproductibles ont été établies pour un matériel tampon, le 4-fluorostyrène-co-pentafluorostyrène-co-[4-(styrèn-4'-yl)-2,3,5,6-tétrafluorophényléther] (bufTxx), pour le matériel de guidage, du styrène-co-pentafluorostyrène-co-4-(styrèn-4'-yl)-2,3,5,6-tétra-fluoro-phényléther] (terTxx), ainsi que leurs précurseurs. Les polymères ont été caractérisés par spectroscopie infrarouge par transformé de Fourier de type réflexion totale atténué (ATR FT-IR), par chromatographie sur gel perméable (GPC), par spectroscopie de résonance magnétique nucléaire de proton (1H RMN), ainsi que par des analyses thermiques. Des motifs de guides d'ondes indépendants et des dispositifs de guide d'ondes à plusieurs couches ont été préparés sur des substrats de silicium. Le polymère agissant comme guide d'ondes a des propriétés de résistances négatives, facilitant une impression lithographique photoinitiée. Ces motifs ont été étudiés par microscopie optique, par microscopie électronique de balayage utilisant un canon à émission de champ (FEG SEM) et par analyse de couplage par prisme. Un laser de 632 nanomètres (HeNe) a été couplé avec succès aux motifs de guide d'ondes imprimées d'une fibre optique.
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Ugarte, Eunate Goiti. "Thermoreversible networks of styrene-based copolymers." Thesis, University of Salford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401910.
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Ma, Yinghua. "Living cationic polymerization of styrene monomers." Thesis, Aston University, 2000. http://publications.aston.ac.uk/9636/.
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This thesis describes an experimental investigation of synthesis of polystyrene under various polymerization conditions such as solvent polarity, temperature, initial concentrations of initiator, catalyst, monomer and added salts or co-catalyst, which was achieved using the living cationic polymerization technology in conjunction with gel permeation chromatography (GPC) and NMR spectroscopy. Polymerizations of styrene were conducted using 1-phenyl ethylchloride (1-PEC) as an initiator and tin tetrachloride (SnCI4) as a catalyst in the presence of tetra-n-Butylammonium chloride (nBu4NCI). Effects of solvent polarity varied by mixing dichloromethane (DCM) and less polar cyclohexane (C.hex), temperature, initial concentrations of SnC14, 1-PEC and nBu4NCI on the polymerizations were examined, and the conditions under which a living polymerization can be obtained were optimised as: [styrene]o ~ 0.75 - 2 M; [1-PEC]o ~ 0.005 - 0.05 M; [SnCI4Jo ~ 0.05 - 0.4 M; [nBu4NCIJo ~ 0.001 - 0.1 M; DCM/C.hex ~ 50/0 - 20/30 v/v; T ~ 0 to -45°C. Kinetic studies of styrene polymerization using the Omnifit sampling method showed that the number average molecular weight (Mn) of the polymers obtained increased in direct proportion to monomer conversion and agreed well with the theoretical Mn expected from the concentration ratios of monomer to initiator. The linearities of both the 1n([MJoI[M]) vs. time plot and the Mn vs. monomer conversion plot, and the narrow molecular weight distribution (MWD) measured using GPC demonstrated the livingness of the polymerizations, indicating the absence of irreversible termination and transfer within the lifetimes of the polymerizations. The proposed 'two species' propagation mechanism was found to apply for the styrene polymerization with 1-PEC/SnCI4 in the presence of nBu4NCl. The further kinetic experiments showed that living styrene polymerizations were achieved using the 1-PEC/SnCI4 initiating system in mixtures of DCM/C.hex 30/20 v/v at -15°C in the presence of various bromide salts, tetra-n-butylammonium bromide, tetra-n-pentylammonium bromide, tetra-n-heptylammonium bromide, and tetra-n-octylammonium bromide, respectively. The types of the bromide salts were found to have no significant effect on monomer conversion, Mn, polydispersity and initiation efficiency. Living polymerizations of styrene were also achieved using titanium tetrachloride (TiCI4) as a catalyst and 1-PEC as an initiator in the presence of a small amount of 2,6-di-tert-butylpyridine or pyridine instead of nBu4NCl. GPC analysis showed that the polymers obtained had narrow polydispersities (P.D. < 1.3), and the linearities of both the In([MJo/[MJ) vs. time plot and the Mn vs. monomer conversion plot demonstrated that the polymerizations are living, when the ratio of DCM and C.hex was less than 40 : 10 and the reaction temperature was not lower than -15°C. The reaction orders relative to TiCl4 and 1-PEC were estimated from the investigations into the rate of polymerization to be 2.56 and 1.0 respectively. lH and 13C NMR analysis of the resultant polystyrene would suggest the end-functionality of the product polymers is chlorine for all living polymerizations.
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Schneider, Ludovic. "Systèmes hybrides photosensibilisateur-laccase pour la catalyse d'oxydation de composés organiques." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4372.
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Les laccases sont des enzymes de type oxydase, réalisant de manière efficace la réduction du dioxygène en eau. Des études réalisées au laboratoire ont permis de montrer que l’irradiation sous atmosphère inerte d’un système de type, EDTA/[Ru(bpy)3]2+/laccase, conduisait à la photoréduction de l’enzyme via la formation d'une espèce [Ru(bpy)3]2+*. La substitution de l’EDTA par un alcène de type p-styrène sulfonate conduit également à la photoréduction de l’enzyme. L'ouverture à l'air du système permet une consommation d’oxygène concomitante à la détection par RMN de produits d’oxydation tels que l’époxyde, le diol et le p-benzaldéhyde sulfonate. L’influence de la concentration des différents partenaires, de la source d’irradiation et du pH sur l’efficacité de cette réaction a été évaluée. D’autres alcènes tels que le styrène, le cyclohéxène ou le cyclooctène sont également substrats. Le marquage isotopique en présence soit d'H218O soit d'18O2 ainsi que l’utilisation de générateurs d’espèces réactives de l’oxygène, ont permis de proposer un mécanisme majoritaire où l’espèce RuIII, photoproduite avec l'assistance de la laccase, pourrait arracher un électron du substrat qui à son tour réagirait avec le dioxygène présent dans le milieu pour conduire aux produits observés. D’autres complexes photoactivables à base de ruthénium ou de manganèse ont également été employés. Afin d’aborder le contrôle de la réactivité, le greffage covalent d’un photosensibilisateur à base de ruthénium sur une lysine unique à proximité du site d'oxydation des substrats de l'enzyme a été effectuéLaccases are oxidases that efficiently perform the reduction of dioxygen into water. Studies in the laboratory have allowed to show that irradiation under inert atmosphere of a EDTA/[Ru(bpy)3]2+/laccase system, lead to the photoreduction of the enzyme via the irradiation of [Ru(bpy)3]2+*. The substitution of EDTA by the alkene p-styrene sulfonate results similarly in a photoreduction of the enzyme. Opening the system to air allows a dioxygen consumption with a simultaneous detection of oxidation products such as the epoxide, diol and p-benzaldehyde sulfonate detected by NMR. The influence of the concentration of the partners, the irradiation source and pH on the efficiency of the reaction was evaluated. Other alkenes such as styrene, cyclohexene and cyclooctene are also substrates. Isotopic labeling experiments in the presence of either H218O or 18O2, as well as the use of reactive oxygen species generators, allowed us to propose a main mechanism where the laccase assisted RuIII photogenerated specie would withdraw an electron from the substrate which in turn would react with dioxygen to yield the products observed. Other ruthenium and manganese photosensitizers were also used. To address the control of the reactivity, a covalent grafting of a ruthenium photosensitizer, on a unique lysine nearby the substrate oxidation site of the laccase was done
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Khan, M. A. "Modified poly(styrene) : Surface analysis and biointeractions." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233675.
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Schneider, Ludovic. "Systèmes hybrides photosensibilisateur-laccase pour la catalyse d'oxydation de composés organiques." Electronic Thesis or Diss., Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4372.
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Les laccases sont des enzymes de type oxydase, réalisant de manière efficace la réduction du dioxygène en eau. Des études réalisées au laboratoire ont permis de montrer que l’irradiation sous atmosphère inerte d’un système de type, EDTA/[Ru(bpy)3]2+/laccase, conduisait à la photoréduction de l’enzyme via la formation d'une espèce [Ru(bpy)3]2+*. La substitution de l’EDTA par un alcène de type p-styrène sulfonate conduit également à la photoréduction de l’enzyme. L'ouverture à l'air du système permet une consommation d’oxygène concomitante à la détection par RMN de produits d’oxydation tels que l’époxyde, le diol et le p-benzaldéhyde sulfonate. L’influence de la concentration des différents partenaires, de la source d’irradiation et du pH sur l’efficacité de cette réaction a été évaluée. D’autres alcènes tels que le styrène, le cyclohéxène ou le cyclooctène sont également substrats. Le marquage isotopique en présence soit d'H218O soit d'18O2 ainsi que l’utilisation de générateurs d’espèces réactives de l’oxygène, ont permis de proposer un mécanisme majoritaire où l’espèce RuIII, photoproduite avec l'assistance de la laccase, pourrait arracher un électron du substrat qui à son tour réagirait avec le dioxygène présent dans le milieu pour conduire aux produits observés. D’autres complexes photoactivables à base de ruthénium ou de manganèse ont également été employés. Afin d’aborder le contrôle de la réactivité, le greffage covalent d’un photosensibilisateur à base de ruthénium sur une lysine unique à proximité du site d'oxydation des substrats de l'enzyme a été effectuéLaccases are oxidases that efficiently perform the reduction of dioxygen into water. Studies in the laboratory have allowed to show that irradiation under inert atmosphere of a EDTA/[Ru(bpy)3]2+/laccase system, lead to the photoreduction of the enzyme via the irradiation of [Ru(bpy)3]2+*. The substitution of EDTA by the alkene p-styrene sulfonate results similarly in a photoreduction of the enzyme. Opening the system to air allows a dioxygen consumption with a simultaneous detection of oxidation products such as the epoxide, diol and p-benzaldehyde sulfonate detected by NMR. The influence of the concentration of the partners, the irradiation source and pH on the efficiency of the reaction was evaluated. Other alkenes such as styrene, cyclohexene and cyclooctene are also substrates. Isotopic labeling experiments in the presence of either H218O or 18O2, as well as the use of reactive oxygen species generators, allowed us to propose a main mechanism where the laccase assisted RuIII photogenerated specie would withdraw an electron from the substrate which in turn would react with dioxygen to yield the products observed. Other ruthenium and manganese photosensitizers were also used. To address the control of the reactivity, a covalent grafting of a ruthenium photosensitizer, on a unique lysine nearby the substrate oxidation site of the laccase was done
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Tang, Chau N. "Copolymerization and Characterization of Vinylaromatics with Fluorinated Styrenes." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1207773730.
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Sheng, Quan. "Functional polymers derived from 4-methylstyrene." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0019/NQ30169.pdf.
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Stubbs, Ian. "Poly(styrene)-b-Poly(dimethylsiloxane)-b- Poly(styrene)/Single Walled Carbon Nanotube Nanocomposites. Synthesis of Triblock Copolymer and Nanocomposite Preparation." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2016. http://digitalcommons.auctr.edu/cauetds/49.
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Molecular weights of 2,000, 6,000 and 10,000 of silane functionalized atactic polystyrene (aPS) and α,ω-divinyl functionalized polydimethylsiloxane (PDMS) were prepared via living anionic polymerization and bulk anionic ring opening polymerization respectively. Functionalization of the homopolymers was confirmed by FT-IR and 1H-NMR spectroscopy and their molecular weights were determined via 1H-NMR end group analysis. A hydrosilylation reaction between the functionalized homopolymers of different molecular weights produced nine polystyrene-block-polydimethylsiloxane-block-polystyrene (aPS-b-PDMS-b-aPS) triblock copolymers. Field emission scanning electron microscopy observations revealed the copolymers self-assemble into supramolecular structures. Dynamic Light Scattering measurements show only small increase in the order of nanometers of its hydrodynamic radius as the individual molecular weights of the homopolymers were increased.
Nanocomposites of the copolymers were prepared by incorporating 1% of oxidized single walled carbon nanotubes (SWNTs) within the aPS-PDMS-aPS matrices via coagulation precipitation. Differential scanning calorimetry (DSC) thermal analysis shows the SWNT interacting with both aPS and PDMS constituting blocks. SWNTs interaction with aPS block either increases the polymer glass transition temperature (Tg) by restricting its segmental motion or decreases the Tg by a plasticization effect. Within the PDMS block the SWNTs act as nucleating sites accelerating the crystallization rate of the polymer. This is evident by the appearance of single and double melting endotherms in the DSC thermograms.
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Del, Nin Jeffrey W. "The nitroxide-mediated polymerization of styrene and isoprene." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq20625.pdf.
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Xie, Min. "Nitroxide-mediated living radical styrene polymerization in miniemulsion." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0020/MQ54494.pdf.
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Marc, Katya. "Thermo-chemical recovery of styrene from polystyrene waste." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61312.
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Styrene was recovered from polystyrene by thermo-chemical treatment in a nitrogen atmosphere carried out at 330$ sp circ$C to 410$ sp circ$C, for 30 to 60 minutes. Up to 70% of the polystyrene was converted to styrene at a reaction temperature of 406$ sp circ$C and reaction time of 45 minutes. The styrene yield increased with temperature. At the lower temperatures, the molecular weight of the polystyrene was reduced from 138 000 to 8 900. At the higher temperatures, the polystyrene residue obtained consisted mainly of styrene dimer and trimer. The use of catalysts was evaluated. The catalysts were mixed with the polystyrene in 10% by weight mixtures. They were: silica-alumina, poly($ alpha$-methylstyrene), an antioxidant (2,2$ sp prime$-Methylenebis(4-methyl-6-tert-butyl phenol)), and zeolite. The above catalysts were found to have no effect on the thermal degradation of polystyrene under the conditions of the present study. The initial rate of thermal degradation of polystyrene was found to fit a first order model. The activation energy obtained was 181 kJ/mol, which is in accordance with literature values.
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Hird, Bryn. "Structure-morphology-property relations in random styrene ionomers." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70303.
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It is generally accepted that in random styrene ionomers the ion-pairs tend to associate to form small aggregates termed multiplets which are embedded in the polymer and act as crosslinks. At sufficiently high ion-contents, ion-rich regions termed clusters are believed to phase-separate from the polymer matrix. In this study, the dynamic mechanical properties of random styrene ionomers containing various concentrations of alkali-metal methacrylate groups were measured over a range of temperatures at several different frequencies. Two peaks are evident in the loss tangent (tan $ delta)$ vs. temperature curves, indicating that the materials are phase-separated, with each tan $ delta$ peak resulting from the glass transition (T$ sb{ rm g})$ of a separate phase. This hypothesis is supported by the magnitudes of the apparent activation energies determined in this study for each transition. The relative heights and areas of the tan $ delta$ peaks indicate that the cluster phase becomes dominant at ion contents above ca. 6 mol %, and that complete phase inversion occurs at relatively low ion-contents. This finding, together with the results of small-angle X-ray studies performed elsewhere, led to the development of a new model for the morphology of random styrene ionomers. The model is based on aggregation of ion-pairs to form multiplets. Each ion-pair in a multiplet effectively anchors the polymer chain to which it is attached, thereby forming a layer of polymer with restricted mobility surrounding the multiplet. Isolated multiplets act as large crosslinks, thus increasing the glass transition temperature of the material. As the ion content is increased, the regions of restricted mobility surrounding each multiplet overlap to form larger contiguous regions of restricted mobility. When these regions become sufficiently large, they exhibit phase-separated behaviour and are termed clusters. The model is in good agreement with a very wide range of experimentally observed p
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Raja, T. M. "Modelling and control of the polymerisation of styrene." Thesis, University of Bradford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503689.
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Gassicke, Le N. "Studies on polymers containing styrene and 4-vinylpyridine." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504461.
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Qureshi, M. S. "A study of styrene-ethylene oxide diblock copolymers." Thesis, University of Strathclyde, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292269.
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Kleman, Angela M. "Asymmetric Hydroformylation of Styrene in Supercritical Carbon Dioxide." University of Toledo / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1116292003.
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Schinazi, Gustavo. "Bio-Based Flame Retardation of Acrylonitrile-Butadiene-Styrene." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1605795004534958.
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Baldassarri, Chiara. "Hydroxylamine-based inhibitors of auto-initiated styrene polymerization." Thesis, University of York, 2014. http://etheses.whiterose.ac.uk/8443/.
Full textAbstract:
The object of this thesis was to investigate the inhibition mechanism of N,N-dibenzylhydroxylamine (DBHA) and 2,5-di-tert-butyl-1,4-benzoquinone (2,5-DTBBQ) mixture towards auto-initiated styrene polymerisation. This non-toxic composition represents a valid alternative to the quite efficient, but harmful 2,4-di-nitro-6-sec-butyl phenol. A dilatometry study revealed that DBHA/2,5-DTBBQ mixture shows synergism, therefore in order to decipher its mechanism of inhibition, the inhibitors were first investigated individually and then together. DBHA is a good inhibitor only in oxygenated systems. The main mechanism of inhibition of DBHA is the quenching of peroxyl radicals at the end of the propagating chains by hydrogen abstraction. In the presence of oxygen N,N-dibenzylnitroxide also contributes to the inhibition to some extent. During the inhibition of styrene with DBHA/2,5-DTBBQ, 2,5-DTBBQ is reduced to 2,5-di-tert-butyl-hydroquinone (2,5-DTBHQ). Dilatometry study revealed that the 2,5-DTBHQ/2,5-DTBBQ mixture shows a limited retardation towards the styrene polymerisation. The ability of these compounds to stop propagation radicals by addition reactions was ruled out, since no addition products were detected. Product analysis of the inhibition of styrene polymerization in the presence of DBHA and 2,5-DTBBQ allowed the detection of a few compounds, which were tested by dilatometry either singularly or as a mixture. This approach provides a way to rule out several molecules as responsible for the synergism of DBHA-2,5-DTBBQ. N,N-Dibenzylnitroxide is formed during the inhibition, and a combination of dilatometry and EPR analyses revealed a correlation between its concentration in the mixture and inhibition time. N,N-Dibenzylnitroxide is likely to be involved in the inhibition but not in the retardation. UV-Vis study confirmed that DBHA and 2,5-DTBBQ form a charge transfer complex, and its role in the inhibition and retardation cannot be excluded.
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Perevosnik, Kathleen A. "Investigation of the Mechanical and Thermal Properties of Poly(styrene-block-isobutylene-styrene) (SIBS) and its Blends with Thymine-Functionalized Polystyrene." Akron, OH : University of Akron, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1226647131.
Full textAbstract:
Thesis (M.S.)--University of Akron, Dept. of Polymer Science, 2008."December, 2008." Title from electronic thesis title page (viewed 01/13/2010) Advisor, Judit E. Puskas; Faculty Reader, Gary R. Hamed; Department Chair, Ali Dhinojwala; Dean of the College, Stephen Z. D. Cheng; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Simmons, Alexandra Hedy. "Physical properties of styrene and ethyl acrylate-based ionomers and their blends with poly(ethylenimine)." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63818.
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Lee, Won Jae. "Ethylbenzene dehydrogenation into styrene: kinetic modeling and reactor simulation." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4847.
Full textAbstract:
A fundamental kinetic model based upon the Hougen-Watson formalism was
derived as a basis not only for a better understanding of the reaction behavior but also
for the design and simulation of industrial reactors.
Kinetic experiments were carried out using a commercial potassium-promoted
iron catalyst in a tubular reactor under atmospheric pressure. Typical reaction conditions
were temperature = 620oC, steam to ethylbenzene mole ratio = 11, and partial pressure
of N2 diluent = 0.432 bar. Experimental data were obtained for different operating
conditions, i.e., temperature, feed molar ratio of steam to ethylbenzene, styrene to
ethylbenzene, and hydrogen to ethylbenzene and space time. The effluent of the reactor
was analyzed on-line using two GCs.
Kinetic experiments for the formation of minor by-products, i.e. phenylacetylene,
ñ-methylstyrene, ò-methylstyrene, etc, were conducted as well. The reaction conditions
were: temperature = 600oC ~ 640oC, a molar ratio of steam to ethylbenzene = 6.5, and partial pressure of N2 diluent = 0.43 bar and 0.64 bar. The products were analyzed by
off-line GC.
The mathematical model developed for the ethylbenzene dehydrogenation
consists of nonlinear simultaneous differential equations in multiple dependent variables.
The parameters were estimated from the minimization of the multiresponse objective
function which was performed by means of the Marquardt algorithm. All the estimated
parameters satisfied the statistical tests and physicochemical criteria. The kinetic model
yielded an excellent fit of the experimental data.
The intrinsic kinetic parameters were used with the heterogeneous fixed bed
reactor model which is explicitly accounting for the diffusional limitations inside the
porous catalyst. Multi-bed industrial adiabatic reactors with axial flow and radial flow
were simulated and the effect of the operating conditions on the reactor performance was
investigated.
The dynamic equilibrium coke content was calculated using detailed kinetic
model for coke formation and gasification, which was coupled to the kinetic model for
the main reactions. The calculation of the dynamic equilibrium coke content provided a
crucial guideline for the selection of the steam to ethylbenzene ratio leading to optimum
operating conditions.
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Yeates, Charl Alan. "Biocatalytic resolution of substituted styrene oxides / Charl Alan Yeates." Thesis, Potchefstroom University for Christian Higher Education, 2001. http://hdl.handle.net/10394/1489.
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Hirst, R. D. "The preparartion and characterisation of cellulose-g.co-styrene systems." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234890.
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Hassan, S. A. "Particle nucleation and growth in emulsion polymerisation of styrene." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377034.
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Zeynali, Mohammad Ebrahim. "Effect of catalyst pore size on styrene production rate." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-186454.
Full textAbstract:
In this study the diffusion coefficients for reaction components were determined for unimodal and bimodal pore size distribution and assuming transitional diffusion regime using a more realistic, Stewart-Johnson, method. It was found that determination of diffusion coefficient using the average pore size results in underestimated values. A comparison was made between the effects of
unimodal and bimodal pore size distribution on diffusion coefficients. The governing differential equation for a single pellet for styrene production was solved by orthogonal collocation method. The effectiveness factor which is a key parameter in reactor design was determined for the reaction in practical range of pore size. It was found that the production rate and effectiveness factor are sensitive to pore size and pore size distribution and with certain pore size distribution a considerable improvement in production rate can be achieved.
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Mpitso, Khotso. "Synthesis and characterization of styrene – maleic anhydride copolymer derivatives." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1972.
Full textAbstract:
Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: In this study, a functional styrene – maleic anhydride copolymer (SMA) was synthesized via reversible addition-fragmentation chain transfer mediated polymerization (RAFT). The obtained copolymer had an alternating structure with well controlled molecular weight. The structure of the copolymer was found to alternating when characterized by NMR and MALDI-Tof-MS. SMA copolymer is functional polymer due to the presence of reactive maleic anhydride moiety in its backbone. The SMA copolymer was used as a starting material for synthesis of other three copolymers with potential anti-viral activity. These three copolymers are referred to as SMA copolymer derivatives because they were synthesized by reacting either maleic anhydride or styrene moieties with certain chemical compounds. The three derived copolymers are; styrene-maleimde copolymer (SMI), styrene sulfonate-maleic anhydride copolymer (SSMA) and styrene sulfonate– maleimide copolymer (SSMI). SMI was synthesized by reacting 4-aminomethylbenzene sulfonamide compound with maleic anhydride moieties on the backbone of SMA copolymer. The reaction proceeded in the presence of co-catalysts triethylamine and dimethylamino pyridine to from amide linkages. The copolymer was characterized by NMR spectroscopy, SEC and FTIR spectroscopy. SSMA copolymer was successfully synthesized by reacting styrene moieties of the SMA copolymers with chlorosulfonic acid. The SSMA copolymer was further reacted with amine compound to synthesize SSMI copolymer. The synthesis of SSMI was achieved by reacting the maleic anhydride moieties in the backbone of the SSMA copolymer with N1,N1- dimethylpropane-1,3-diamine. Both copolymers were successfully characterized by FTIR spectroscopy.
AFRIKAANSE OPSOMMING: 'n Funksionele stireen-maleïensuuranhidried (SMA) kopolimeer is berei d.m.v. omkeerbare addisie-fragmentasie ketting-oordrag-beheerde (OAFO) polimerisasie. Die polimere het 'n wissellende struktuur en goed beheerde molekulêre massa gehad. Die wisselende struktuur is bevestig d.m.v. KMR en MALDI-ToF analise. Die SMA kopolimeer is funksioneel a.g.v. die teenwoordigheid van reaktiewe anhidriedgroepe in die polimeerrugraat. Hierdie SMA kopolimeer is gebruik as uitgangstof vir die bereiding van drie ander kopolimere met potensiele teenvirale-aktiwiteit: stireenmaleïimied kopolimeer (SMI), stireensulfonaat-maleïensuuranhidried kopolimeer (SSMA) en stireensulfonaat-maleïimied kopolimeer (SSMI). Hiedie kopolimere staan bekend as SMA-kopolimeerderivate omdat hulle berei is deur d.m.v. die reaksie van of maleïensuuranhidried of stireengroepe. SMI is suksesvol berei d.m.v. die reaksie van 4-aminobenseensulfonamied met maleïensuuranhidriedeenhede op die polimeerruggraat in die teenwoordigheid van die kokataliste trietielamien of dimetielaminopiridien, om sodoende amiedbindings te vorm. Die kopolimere is gekarakteriseer m.b.v. grootte-uitsluitings-chromatografie (SEC), KMR en FTIR. Die SMMA kopolimeer is suksesvol gesintetiseer d.m.v. die reaksie van die stireeneenhede van die SMMA kopolimeer met chlorosulfoonsuur. Die SSMA kopolimeer is verder gereageer met amienverbindings om die SSMI kopolimeer te lewer. SMMI kopolimere is berei d.m.v. die reaksie van die maleïensuuranhidriedgroepe in die ruggraat van die SSMA kopolimeer met N',N'-dimetielpropaan-1,3-diamien. Albei kopolimere is suksesvol gekarakteriseer m.b.v. KMR en FTIR.
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Liu, Cheng-Wei, and 劉正偉. "Styrene Microemulsion / Microemulsion Polymerization of Styrene - Effect of Cosurfactants." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/71656007687402973847.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
87
This study produced transparent oil in water styrene microemulsions comprising water, styrene, sodium dodecyl sulfater, and cosurfactant (1-pentanol, 1-butanol, 1-hexanol, C4E1, C4E2, C6E1, C6E2, HEMA, or HPMA). The pseudo-phase diagram indicates the followings : 1. By increasing the concentration of more hydrophobic cosurfactant (such as 1-pentanol, 1-hexanol, C6E1, or C6E2), emulsion experienced three phases, that is, from milky, to transparent and then to gel-like. The longer the length of the carbon chain of cosurfactant, the narrower is the region of microemulsion. When Microemulsion changed from transparent to gel-like, the viscosity of the sample increased and conducitvity dropped suddenly. 2. By increasing the concentration of more hydrophilic cosurfactant (such as 1-butanol, C4E1, C4E2, HEMA, or HPMA), emulsion changed from milky to transparent, but lamellar structure was not observed. The longer the EO group of cosurfactant, the broader is the region of microemulsion. When the concentration of cosurfactant increased, the viscosity of sample only decreased slightly as well as the conductivity. By adding water—soluble persulfate initiator to microemulsion at 70 ℃, microemulsion polymerization starts. When increasing the concentration of cosurfactant, the particle size of the microlatex increased slightly, but polymer molecular weight decreased. By using more hydrophilic cosurfactant such as C4E1, or C4E2, polymer molecular weight became smaller. On the other hand, polymer molecular weight became larger by using more hydrophobic cosurfactant such as 1-butanol. When the concentration of styrene increased, both the particle size of the microlatex and polymer molecular weight increased. Although HEMA and HPMA could produce stable and transparent microemulsions, stable latexes were not produced.
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Tung, Kevin. "Oxygen scavenging styrene-butadiene-styrene block copolymer films for barrier applications." 2013. http://hdl.handle.net/2152/21164.
Full textAbstract:
This dissertation discusses the oxidation behavior of reactive membranes that were produced by solution casting and by melt extrusion. These films, containing styrene-butadiene-styrene (SBS) block copolymer that undergoes catalytic oxidation, are of potential use as an oxygen scavenging polymer (OSP) for barrier applications. A thin film kinetic model was developed to ascertain reaction parameters that were used to describe thick film oxidation behavior. Ultimately complex structures containing these scavengers need to be produced via melt-extrusion. Therefore, processing conditions were established to ensure that melt-processed films have the same oxidation kinetics and capacity as those prepared by solution casting. Blends containing a non-reactive styrene phase and an oxygen-scavenging SBS phase were extruded and, by uptake and permeation experiments, their oxidation behaviors were monitored. The flux behavior and time lag extension as a function of oxygen pressure, film thickness, SBS scavenger and photoinitator contents were measured and compared to the theoretical model. The permeation behavior of the reactive blend films containing SBS showed that time lags can be extended via an oxidative mechanism and barrier properties be improved compared to traditional packaging membrane of native polystyrene.text
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Liu, Tzu Chi, and 劉子琦. "Separation of styrene from the mixture of styrene and mixed xylenes." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/55437782819237635658.
Full textAbstract:
碩士長庚大學
化工與材料工程研究所
96
A new separation technique, called distillative freezing (DF), is introduced in this work to purify styrene (ST) from the mixture consisting of styrene (ST), ethylbenzene (EB), p-xylene (PX), m-xylene (MX) and o-xylene (OX). In principle, DF is operated at a triple point condition, in which the liquid mixture is simultaneously vaporized and crystallized due to the three phase equilibrium. Thus, DF is a distillative crystallization technology, which combines distillation and crystallization to produce pure crystals. The DF experiments show that the purity of ST can only be purified from 0.85 to 0.953, from 0.90 to 0.960, or from 0.95 to 0.972 in the binary mixture of ST and EB. On the other hand, the DF experiments show that the purity of ST can be purified from 0.85 to 0.98 or from 0.90 to 0.99 in the mixture consisting of ST, EB, PX, MX and OX. Thus, DF provides an efficient separation method to separate ST from the mixture consisting of ST and the mixed xylenes.
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TSAI, SHIH CHANG, and 蔡世璋. "Properties of styrene-butadiene-styrene triblock copolymer membranes prepared by epoxidation method." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/07389363733748052452.
Full textAbstract:
碩士長庚大學
化工與材料工程研究所
96
Epoxy group modified the surface of styrene-butadiene-styrene triblock copolymer membrane (ESBS) could be created by utilizing performic acid (HCOOOH) to break C=C of styrene-butadiene-styrene. The physiochemical characteristics of the ESBS membranes were determined by FTIR, TGA, DSC, contact angle, and water content. Furthermore, protein adsorption and cell culture tests were performed to determine the biocompatibility of ESBS. According to the results of FTIR, it was found the epoxy group on membrane surface increased with increasing epoxidation time. In addition to, the thermal properties of ESBS would reduce when the eposidation time was increased. The results determined by contact angle and water content also showed that the membranes became more hydrophilic when the epoxidation time was increased. The fibrinogen adsorption on ESBS membrane surface showed that protein adsorption increased due to the increment of epoxy group on membrane surface. When 3T3 fibroblasts were cultured on these membranes, it was found the number of cells adhering initially on the membrane surface would reduce when the content of epoxy groups increased, but the growth rate increase.
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許佃榕. "Styrene emulsion polymerization kinetics." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/34144582283121044303.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
87
Batch emulsion polymerizations of styrene in a well mixed stirred tank were carried out at 400 rpm, with sodium persulfate as the initiator and sodium dodecyl sulfate (SDS) and nonylphenol polyethoxylate with 40 ethylene oxide units per molecule (NP40) as the surfactant. The effects of temperature, the NP40 concentration and the composition of the mixed SDS/NP40 surfactants were investigated in this work. The experimental results show that: (1) Both the polymerization rate (Rp) and number of latex particles generated (Np) increases with increasing temperature (T = 50 → 80℃), whereas both the weight-average particle size (dw) and average number of free radicals per particle (□ ) decrease with increasing T. (2) At 60℃, both Rp and Np increase with increasing NP40 concentration ([NP40]) and Np ~ [NP40]2.36. In this series of experiments, dw decreases with an increase in [NP40]. It is also interesting to note that a small population of tiny monomer droplets is still present in the reaction system. (3) At constant temperature (60 ℃) and concentration of micelles, the values of Rp and Np obtained from the polymerization with NP40 as the surfactant are much smaller than the SDS counterpart. (4) At 60 ℃, the values of Rp and Np seem to be insensitive to changes in the ratio of SDS to NP40 (SDS/NP40 =3/1, 1/1, and 1/2). The population of monomer droplets disappear when the monomer conversion is above 88%.
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LI, SHENG-FENG, and 李勝豐. "Microemulsion polymerization of styrene." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/73319618513824311815.
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WANG, BAOYU. "PROPERTIES OF STYRENE-DIMETHYLSILOXANE BLOCK COPOLYMERS AND STYRENE-DIMETHYLSILOXANE DIBLOCK COPOLYMER/POLYSTYRENE HOMOPOLYMER BLENDS." Thesis, 1987. http://hdl.handle.net/1911/16122.
Full textAbstract:
Styrene-dimethylsiloxane (S-DMS) di- and triblock copolymers, whose overall molecular weight ranged from 3,800 to 4.7 $\times$ 10$\sp5$, and styrene contents from 4 to 96%, were studied using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy. Blends of the S-DMS diblock copolymer and PS homopolymer with PS weight fraction ranging from 0.04 to 0.96 for two different PS to S block molecular weight ratios, 30:1 and 1:50, were also studied by DSC.
Comparisons of calculated and the experimental specific heat, C$\sb{\rm p}$, were made to estimate the relative error in C$\sb{\rm p}$ measurements and the percent mixing of block chains in their opposite microphase.
The occurrence of DMS microphase crystallization depends on the DMS block molecular weight, but the degree of crystallinity depends both on weight percent of DMS and on the cooling rate. The critical DMS block molecular weight at which the DMS microphase crystallize under the experimental conditions used in this work is between 3,800 and 15,400.
The glass transition temperature, T$\sb{\rm g}$, of fully amorphous DMS microphases is influenced by the overall composition of each sample. The T$\sb{\rm g}$ of semicrystalline DMS microphases is affected by the degree of crystallinity of the DMS microphases. The variation in DMS microphase T$\sb{\rm g}$ were attributed to a thermal stress effect.
The number of styrene T$\sb{\rm g}$'s in each blend was used to characterize the mixing of PS and the S blocks. The weight fraction of styrene segments in each styrene phase was calculated from the heat capacity change at T$\sb{\rm g}$. In styrene phase separated blends, the weight fraction of each styrene phase varied with the annealing temperature. A phase diagram was constructed for the blends with 30:1 PS to S block molecular weight ratio.
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WANG, BING-HAO, and 王秉豪. "Study of the Mechanical Properties of Polystyrene/Barium sulfate/Styrene-butadiene-styrene Copolymer Blends." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/4tmc38.
Full textAbstract:
碩士萬能科技大學
材料科學與工程研究所在職專班
105
In this study, Polystyrene (PS) / barium sulfate (BaSO4) / styrene-butadiene-styrene copolymer (SBS) composites were prepared by melt compounding and mixed with barium sulphate in different content.The mixture was kneaded at a temperature of 180-260 ℃ through a twin-screw extruder. The samples were prepared by injection molding and tested according to ASTM standards. We examined mechanical and physical properties of different compounding. We discussed melt index analysis, tensile property test, flexural strength test, impact strength, the results revealed the use of barium sulfate (BaSO4) can the processing required flow index can be adjusted by the ratio. Adjustment of BaSO4 / SBS proportions can obtain different mechanical properties of the materials. In accordance with different needs, such as the tensile properties of good circumstances can choose PS / SBS 5% of its BaSO4 addition of 10-20%, bending strength of good circumstances can choose PS / BaSO4 / SBS ratio of 45/50 / 5, good impact strength can be used in the case of PS / SBS 10% of its BaSO4 can choose to add 10-30%, so the compounding can be adjusted according to different requirements in response to the need of material industry.
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熊明恕. "The Order－Disorder Transition Of Poly(styrene -block- ethylene / butylene -block- styrene) / Polystyrene Blends." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/74007639007469703942.
Full textAbstract:
碩士逢甲大學
紡織工程學系
89
The order-disorder transition of block copolymer SEBS and it’s homopolymer PS blends was investigated in this study. The KRATON G, produced by Shell Company, and PS was made into the thin film in the experiment. The differential scanning calorimetry (DSC) and the dynamic mechanical analysis (DMA) was used to find out the order-disorder transition temperature (TODT) of the SEBS/PS blend. The experiment results shown that macrophase separation occurs when the SEBS/PS blend ratio was more than 70/30. In the DSC plots, we find the TODT would be increasing as the PS increasing. In this paper we heve shown that plots of dynamic storage modulus (E¢) versus temperature (T), frequencies (ω), or dynamic loss modulus (E²) are effective in determining the TODT. And the TODT also increased when the PS ratio increased in the SEBS/PS blend system.
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Wang, Bo Yan, and 王博彥. "Sulphonated poly(styrene-ethylene/butylene-styrene) (sSEBS) solid electrolytes for direct methanol fuel cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/10163295170516226632.
Full textAbstract:
碩士長庚大學
化工與材料工程學系
100
In this study, using sulfonated SEBS poly (styrene-b-ethylene-butylene-b-styrene) used in direct methanol fuel cell (DMFC) proton exchange membrane, and compared cross-linking agents (EG (Ethylene glycol), PVA (Polyvinyl alcohol), G (glycerol)) effect the DMFC performance. In this study we found that when the feed concentration of 1M methanol 60 ° C using PVA cross-linked (PVA-sSEBS) has the maximum power of 94.5 mW cm−2, higher than of Nafion® 117 performance 33.8%, and when the voltage is 0.3V operating current is also increased by 29.6%; the other hand, using a commercially available cross-linked by Silane to filled the thin film of porous Teflon (Polytetrafluoroethylene (PTFE)) apply in the DMFC, when the feed concentration with 1M methanol and 60C the maximum power is 79.5 mW cm−2 was better than Nafion®115 4.6%. In other hand, based on Kulikovsky model, to simulate the Nafion®117 and compare experimental data curves with the temperature was 60°C the error is 1%; the simulation attempts to simulate the other membranes, such as, sPPEK (Sulfonated poly (phthalazinone ether ketone)) 2M methanol and 80°C the experimental values and prediction errors of the maximum power was 3.6%, sPEEK (Sulfonated poly (ether, ether, ketone)) prediction error was 22.9%, the PTFE/si-sSEBS prediction error is 8.8%, so after modified simulation formula was more closer to the experimental data.
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Lee, Heng-Hsien, and 李恒賢. "STUDIES ON MODIFICATION OF STYRENE-BUTADIENE-STYRENE BLOCK COPOLYMER AND THEIR USE IN TRANSDERMAL PATCHES." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/64398706459964196916.
Full textAbstract:
碩士大同大學
化學工程研究所
90
Graft polymerization of acrylic acid (AA) onto styrene-butadiene-styrene (SBS) using benzoyl peroxide as initiator was studied. The influence of various factors of grafting reaction on grafting percentage of acrylic acid onto SBS-g-AA was also discussed in the study. Experimental results showed that the formation of SBS-g-AA increased with increasing in the concentration of AA. The maximum grafting percentage of SBS-g-AA was observed when the molar ratio of AA to butadiene was 2.5. An interesting observation was that an excess of AA caused a poor grafting reaction. In addition, the increasing reaction time enhanced the formation of SBS-g-AA; the maximum grafting percentage was observed at 3h reaction. Next, graft polymerization of hydrophilic monomers onto SBS by UV-irradiation was studied. Characterization of grafted membranes and the influence of various factors of grafting reaction on grafting percentage were studied. XPS and SEM results confirm the photografting by UV-irradiation was performed successfully. Experimental results showed that formation of grafting copolymer enhanced as monomers increased except for AA series. The decrease in grafting percentage at higher AA concentration may be due to the high reactive of the AA monomer, resulting in the excess formation of the homopolymer. Increasing reaction time also enhanced formation of grafting copolymer. Wettability of modified SBS membrane has been improved. The main propose of this study is to introduce different hydrophilic polymers, such as super absorbent polymer (SAP) and grafted copolymer (SBS-g-AA) into transdermal film to enhance its drug release and improve its peel strength. The results showed that the drug release amount of transdermal film containing grafted copolymer had been apparently improved (from 198μg/cm2 to 352μg/cm2). And its drug release mechanism tended to non-Fickian diffusion. The drug release behaviors of matrices added SAP was not better than those added with grafted copolymer. The matrices containing more amount of the model drug (Indomethacin), the more amount of drug was released. Moreover, the thickness of transdermal films also influenced drug release behavior. The thicker transdermal film contained more drug and released more. But the relative release percentage of thicker matrix was not higher than thinner one. In the other way, the transdermal films, introducing into SAP improved their peel strength.
50
Lin, kuhsi, and 林谷錫. "Syndiospecific copolymerization of styrene with methylstyrene-terminated styrene macromonomer by Cp*Ti(OMe)3-MAO catalyst." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/61818844138094675941.
Full textAbstract:
碩士國立中正大學
化學工程研究所
89
Syndiotactic polystyrene( sPS ) has many good properties such as high melting point (Tm=270℃)、high glass transfer temperature (Tg=100℃)、high degree of crystallinity、good hardness and fast rate of crystallization. However, the high crystallinity of sPs causes brittleness and tends to break easily upon stress. Because the crystallinity varies with the synthesis conditions, sPS can be a better material with greater use if containing anther polymer in its molecular structure. Therefore this study, anion polymerization was proceeded to construct this uniform length atactic functionalized polystyrene with uniform length, followed by the use of Metallocene catalyst to do its syndiotactic copolymerization with styrene. The resulting molecule is a syndiotactic polystyrene grafted with atactic polystyrene side chains.