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1
Shenton, Martyn James. "Investigations of polysiloxane materials." Thesis, University of York, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284120.
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Watts, Andrew M. "Polysiloxane supported metal catalysts." Thesis, University of Bath, 1986. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370993.
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Dalla, Palma Matteo. "Polysiloxane based neutron detectors." Doctoral thesis, Università degli studi di Trento, 2016. https://hdl.handle.net/11572/368462.
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In the last decade, neutron detection has been attracting the attention of the scientific community for different reasons. On one side, the increase in the price of 3He, employed in the most efficient and the most widely used neutron detectors. On the other side, the harmfulness of traditional xylene based liquid scintillators, used in extremely large volumes for the detection of fast neutrons. Finally, the demand for most compact and rough systems pushed by the increased popularity of neutron imaging, neutron scattering and neutron diffraction techniques.
Polysiloxanes could help addressing some of the existing issues regarding neutron detection thanks to their unique properties. For this reason, in this work, polysiloxane scintillators have been developed and characterized, with a special attention to their optical properties and their time response. In particular, this thesis describes the investigation of the scintillation performances of several different polysiloxane liquids. The results have been connected with the optical properties of the material, in turns linked to its molecular structure, allowing to select the most suitable polysiloxane solvent for liquid scintillators. The timing properties of scintillating mixtures employing the best performing polysiloxane solvent were consequently analyzed as a function of the primary dye concentration, with a special focus to the pulse shape discrimination (PSD) capability of the material. PSD is indeed one of the most important characteristic of liquid scintillators, and one of the factors determining their large use. Beside polysiloxane liquids, time response of polysiloxane plastic scintillators was also investigated with the aim of studying their PSD capability. At the moment, indeed, only few examples of plastic scintillators capable of PSD exist, and also in those cases some criticalities emerged connected with stability issues and efficiency. Production of red emitting polysiloxane plastic scintillators is also described in this work, analyzing the energy transfer process between dyes in order to optimize the readout with an avalanche photodiode. This would allow overcoming some issues connected with the use of photomultiplier tubes, in more compact and rugged systems.
Finally some preliminary results about the HYDE experiment are presented. This project aims at the development of a hybrid detector for neutrons, combining a 3D silicon diode with a suitable neutron converter, in order to produce a compact efficient neutron detector with good spatial resolution. With this goal different types of converters for fast and thermal neutrons were tested and the performances of 3D and planar devices were compared.
4
Dalla, Palma Matteo. "Polysiloxane based neutron detectors." Doctoral thesis, University of Trento, 2016. http://eprints-phd.biblio.unitn.it/1713/1/PhDThesis_Dalla_Palma_image.pdf.
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In the last decade, neutron detection has been attracting the attention of the scientific community for different reasons. On one side, the increase in the price of 3He, employed in the most efficient and the most widely used neutron detectors. On the other side, the harmfulness of traditional xylene based liquid scintillators, used in extremely large volumes for the detection of fast neutrons. Finally, the demand for most compact and rough systems pushed by the increased popularity of neutron imaging, neutron scattering and neutron diffraction techniques.
Polysiloxanes could help addressing some of the existing issues regarding neutron detection thanks to their unique properties. For this reason, in this work, polysiloxane scintillators have been developed and characterized, with a special attention to their optical properties and their time response. In particular, this thesis describes the investigation of the scintillation performances of several different polysiloxane liquids. The results have been connected with the optical properties of the material, in turns linked to its molecular structure, allowing to select the most suitable polysiloxane solvent for liquid scintillators. The timing properties of scintillating mixtures employing the best performing polysiloxane solvent were consequently analyzed as a function of the primary dye concentration, with a special focus to the pulse shape discrimination (PSD) capability of the material. PSD is indeed one of the most important characteristic of liquid scintillators, and one of the factors determining their large use. Beside polysiloxane liquids, time response of polysiloxane plastic scintillators was also investigated with the aim of studying their PSD capability. At the moment, indeed, only few examples of plastic scintillators capable of PSD exist, and also in those cases some criticalities emerged connected with stability issues and efficiency. Production of red emitting polysiloxane plastic scintillators is also described in this work, analyzing the energy transfer process between dyes in order to optimize the readout with an avalanche photodiode. This would allow overcoming some issues connected with the use of photomultiplier tubes, in more compact and rugged systems.
Finally some preliminary results about the HYDE experiment are presented. This project aims at the development of a hybrid detector for neutrons, combining a 3D silicon diode with a suitable neutron converter, in order to produce a compact efficient neutron detector with good spatial resolution. With this goal different types of converters for fast and thermal neutrons were tested and the performances of 3D and planar devices were compared.
5
Thoss, Henner. "Hydrophile Polysiloxane als waschbeständige Textilhilfsmittel." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=983646309.
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Hollingshurst, Julien. "Equilibria and dynamics in polysiloxane systems." Thesis, University of York, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306281.
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Dastjerdi, R., F. A. Sadrabadi, and S. Bahrizadeh. "Polysiloxane Sheltered Nanoparticle-Containing Intercalated Nanolayers." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35374.
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In previous researches, we have reported using cross-linkable polysiloxane (XPs) as a guideline for the
design of a novel technique to stabilize different nanostructures on the textile surfaces. This followed by
creating multiple-size nano-roughness on the textile surfaces using oppositely charged inorganic nanoparticles
and cross-linkable polysiloxane resin to develop durable multifunctional textiles. In present study,
creating multiple-size nano-roughness on the textile surfaces has been targeted via using nano-layers accompanied
with nanoparticles for the textile modifications. A colloidal solution of nanoparticle-containing
intercalated nanolayers has been prepared via pre-mixing of nanoparticles and nanolayers under ultrasound
irradiation. Then, fabrics have been treated with the colloidal solution via the ultrasound–assistant
exhaustion process. To compare the effect of combining nanoparticles and nanolayers, some samples were
also produced in the absence of each component. Then, cross-linkable polysiloxane resin has been applied
as a post-treatment on the nano-functionalized fabrics. The hydrophobic features of modified fabrics have
been examined. According to the results, water droplet absorption time and contact angle of water droplets
have been significantly increased via using the nanoparticle-containing intercalated nanolayers.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35374
8
Phillipps, Roy G. "Metal containing polysiloxane derivatives as catalysts." Thesis, University of Bath, 1988. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381898.
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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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Brown, Michael Edward. "APPROACHES TO MOLECULAR IMPRINTING ON POLYSILOXANE SCAFFOLDS." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_theses/469.
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Molecular imprinting, a common method used in separations and chromatography to isolate specific molecules via surface binding, has been adapted for applications in biomaterials and related sciences. The objective of this study was to determine the effectiveness of different approaches to molecular imprinting by testing for preferential binding of protein on polysiloxane scaffold surfaces. To test preferential rebinding, the scaffolds were exposed to a mixture of the template protein and a competitor protein with similar size but different chemistry. Lysozyme-imprinted polymers rebound 8.13 0.99% of lysozyme without any competition and 5.1 0.3% of the protein during competition. Lysozyme C peptide was imprinted into polysiloxane scaffolds to investigate the epitope approach to molecular imprinting. Without competition, 8.95 11.53% of the lysozyme preferentially bound to the scaffolds, while under competition 1.85 9.47% bound to the scaffolds. Lastly, bone morphogenetic protein 2 (BMP-2) was imprinted into the polymer scaffolds. Results revealed that BMP-2 imprinted scaffolds bound 10.09 6.625% under noncompetitive conditions and a very small 0.65 4.55% during competition. Trends of preferential binding via peptide imprinting and BMP-2 imprinting can be seen, and show promise in future tissue engineering material applications and biomaterial compatibility.
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Mecham, Sue Jewel. "Gas permeability of polyimide/polysiloxane block copolymers." Thesis, Virginia Tech, 1994. http://hdl.handle.net/10919/43136.
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A series of perfectly alternating polyimide/ poly(dimethylsiloxane) microphase separated block copolymers ranging from 0-50 wgt. % poly(dimethylsiloxane) have been measured for permeability characteristics. The polyimide segment of the copolymers was based on oxydiphthalicdianhydride (ODPA) and 1,4-Bis(4-amino-1,1- dimethylbenzyl)benzene (Bis P). The polysiloxane was an aminopropyl terminated poly(dimethylsiloxane). Randomly segmented block copolymers of =20 wet. % poly(dimethylsiloxane) with different segment lengths were also studied, based on the same materials for the sake of comparison with the perfectly alternating versions of the same block copolymers. Permeability measurements were performed on tough, microphase separated, transparent films with O₂, N₂, CH₄, and CO₂ gases in that order. The effects of the chemical composition and block lengths on permeability coefficients and selectivity values were evaluated. The permeability of copolymer films to gases was found to be highly sensitive to the morphology of the copolymer. The morphology was found to be controlled by varying the amount and the segment length of each component and this allowed for fine control of the permeability characteristics. Conversely, the measurement of permeability characteristics can lead to more information about the morphology of complicated microphase separated block copolymers.Master of Science
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Alrashed, Maher M. "Polyurethane/Polysiloxane Ceramer Coating for Aircraft Applications." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1386679739.
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Brandt, Patricia J. Andolino. "Polysiloxane-polyarylester block copolymers: synthesis and characterization." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/49991.
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Passive damping has been defined as a key element in vibration control. It is believed that the approach to passive damping could be addressed through the use of carefully designed viscoelastic polymeric materials. This dissertation describes the synthesis and characterization of multiphase, transparent block copolymers that are potential candidates for passive damping applications in large space structures.
Relatively high molecular weight polysiloxane-polyarylester block copolymers were prepared by two different synthetic routes. A solution technique was used to synthesize well-defined, perfectly alternating block copolymers by reacting a difunctional silylamine—terminated siloxane oligomer with a difunctional hydroxyl-terminated polyarylester oligomer. A second approach involved the preparation of a segmented (or random) block copolymer by an interfacial, phase—transfer technique in which various polyarylester block lengths are formed during the copolymerization by reacting bisphenol-A, terephthaloyl chloride, and isophthaloyl chloride with a difunctional aminopropyl-terminated siloxane oligomer. To vary the miscibility of the siloxane and ester phases, and in turn the physical properties of the block copolymers, the block molecular weights and the siloxane block compositions (dimethyl, dimethyl-diphenyl, or dimethyl-trifluoropropylmethyl) were controlled.
Structure analysis by NMR (proton and silicon) and FTIR verified that the desired starting oligomers and block copolymers were successfully prepared. Intrinsic viscosity measurements, size exclusion chromatography, and the fact that tough transparent films could be solution cast and compression molded indicated that relatively high molecular weight materials were prepared.
Due to the high degree of incompatibility of the "soft" siloxane segments and the "hard" ester segments in the block polymers, a two-phase microstructure developed at relatively low block molecular weights. In addition to microphase separation, partial phase mixing was apparent from thermal, mechanical, and microscopic characterization techniques. Compared to a polyarylester homopolymer, the siloxane modified polyarylester block polymers displayed improved resistance to atomic oxygen degradation as seen from x-ray photoelectron spectroscopy and scanning electron microscopy. All physical properties were found to be dependent upon siloxane block composition and copolymer block molecular weights.
In conclusion, new siloxane-ester block copolymers were prepared and characterized. They are believed to be potentially useful materials for passive damping applications in the space environment.Ph. D.
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Mecham, Sue J. "Gas permeability of polyimide/polysiloxane block copolymers /." This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06112009-063219/.
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Arslan, Ahu. "Immobilization Of Tyrosinase In Polysiloxane/polypyrrole Copolymer Matrices." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12606988/index.pdf.
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Immobilization of tyrosinase in conducting copolymer matrices of pyrrole functionalized polydimethylsiloxane/polypyrrole (PDMS/PPy) were achieved by electrochemical polymerization. The polysiloxane/polypyrrole/tyrosinase electrode was constructed by the entrapment of enzyme in conducting matrices during electrochemical copolymerization. Maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were investigated for immobilized enzyme. Enzyme electrodes were prepared in two different electrolyte/solvent systems. The effect of supporting electrolytes, p-toluene sulfonic acid and sodium dodecyl sulfate on the enzyme activity and film morphology were determined. Temperature and pH optimization, operational stability and shelf-life of enzyme electrodes were also examined. Phenolic contents of green and black tea were determined by using enzyme electrodes.
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ZHANG, CHENG. "PIGMENTED POLYURETHANE/POLYSILOXANE HYBRID COATINGS FOR CORROSION PROTECTION." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1495381409246105.
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Zanazzi, Enrico. "Organic and hybrid polysiloxane-based scintillators and passive dosimeters." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/268426.
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The growing interest towards polysiloxane-based radiation detection systems is related with the several advantages that polysiloxanes offer in comparison with other state-of-the-art plastic materials used in scintillation, like polyvinyltoluene and polystyrene. In this respect, polysiloxane elastomers offer higher thermal stability, flexibility and radiation hardness than the traditional plastic counterpart. For this reason, the study of polysiloxane-based systems for the detection of several types of radiation such as neutrons, high-energy photons and charged particles has recently received increasing attention by the scientific community. In this thesis, we report the current advances on both organic and hybrid polysiloxane-based radiation detection systems for scintillation and passive dosimetry applications. In this framework, we will start from the recent advances on organic polysiloxane-based scintillators for the detection of fast neutrons, with particular emphasis on their pulse-shape discrimination capabilities, allowing for the distinction of neutrons from the γ-ray background. The other and main part of the thesis will be then dedicated to hybrid nanostructured polysiloxane-based radiation detection systems. In this context, latest progress on polysiloxane scintillators embedding 6LiF nanocrystals for thermal neutron detection will be presented, with particular focus on the role of the nanocrystal size and dispersion in the detection performances. Subsequently, polysiloxane/quantum dots nanocomposites will be investigated for their possible use in both scintillation and passive dosimetry. In this latter application, the optical properties of the samples are analyzed after irradiation, with the aim to correlate the radiation-induced effects with the radiation dose. Lastly, the role of the polymer matrix in the post-irradiation optical response of the nanocrystals will be investigated.
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Zanazzi, Enrico. "Organic and hybrid polysiloxane-based scintillators and passive dosimeters." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/268426.
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The growing interest towards polysiloxane-based radiation detection systems is related with the several advantages that polysiloxanes offer in comparison with other state-of-the-art plastic materials used in scintillation, like polyvinyltoluene and polystyrene. In this respect, polysiloxane elastomers offer higher thermal stability, flexibility and radiation hardness than the traditional plastic counterpart. For this reason, the study of polysiloxane-based systems for the detection of several types of radiation such as neutrons, high-energy photons and charged particles has recently received increasing attention by the scientific community. In this thesis, we report the current advances on both organic and hybrid polysiloxane-based radiation detection systems for scintillation and passive dosimetry applications. In this framework, we will start from the recent advances on organic polysiloxane-based scintillators for the detection of fast neutrons, with particular emphasis on their pulse-shape discrimination capabilities, allowing for the distinction of neutrons from the γ-ray background. The other and main part of the thesis will be then dedicated to hybrid nanostructured polysiloxane-based radiation detection systems. In this context, latest progress on polysiloxane scintillators embedding 6LiF nanocrystals for thermal neutron detection will be presented, with particular focus on the role of the nanocrystal size and dispersion in the detection performances. Subsequently, polysiloxane/quantum dots nanocomposites will be investigated for their possible use in both scintillation and passive dosimetry. In this latter application, the optical properties of the samples are analyzed after irradiation, with the aim to correlate the radiation-induced effects with the radiation dose. Lastly, the role of the polymer matrix in the post-irradiation optical response of the nanocrystals will be investigated.
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Zhou, Tingting. "Mechanical Analysis of Polycarbonate/Polysiloxane Block Copolymers and Blends." Thesis, North Dakota State University, 2013. https://hdl.handle.net/10365/26869.
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Polydimethylsiloxane (PDMS) can be used to react with polycarbonate (PC) to generate PC-PDMS multiblock copolymers and PC/PC-PDMS-PC triblock blends to overcome the notch sensitivity of PC while maintaining its transparency. It was found in this study that PDMS can act as a rubber particle to absorb energy and promote multicrazing. As a result, the incorporation of PDMS can increase PC's toughness. Meanwhile, high optical clarity can be observed even at 62 wt% PDMS in the multiblock copolymers with uniform morphology. However, PC/PC-PDMS-PC triblock blends damage PC's transparency and become opaque due to the phase separation. Furthermore, compared to compression molding, injection molding introduces shear due to the decrease of the area at the nozzle, which leads to the orientation of polymer chains and, subsequently, better properties of specimens.
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Yixiao, Feng. "ZINC ALUMINUM PHOSPHATE PIGMENTED POLYURETHANE/POLYSILOXANE COATINGS FOR ANTICORROSION." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1525950059586312.
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TOURAUD, FRANCK. "Synthese et caracterisation de copolymeres a bloc polyamide-polysiloxane." Paris 6, 1992. http://www.theses.fr/1992PA066351.
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Ce travail decrit la synthese d'un nouvel elastomere thermoplastique par couplage de blocs polyamide a extremites diamine et de blocs polydimethylsiloxane a terminaisons di(propyloxy-4 benzaldehyde). Ce copolymere est prepare selon deux procedes: par polycondensation en masse; par polycondensation en solution dans le dimethylsulfoxyde. La reaction de couplage est tres rapide et permet la compatibilisation macroscopique des deux blocs initialement immiscibles. Par differentes modelisations, nous avons mis en evidence la participation de reactions secondaires au-dela d'une duree seuil de polycondensation: reactions d'echange a l'interieur des chaines siloxane et amide, et au niveau des jonctions imine. Ces reactions augmentent la dispersite du milieu reactionnel; reticulation par polycondensation en masse; degradation par polycondensation en solution. Les caracteres thermoplastique et elastomere pourront etre modules en agissant sur la longueur relative des deux blocs
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Beigbeder, Alexandre. "Élaboration et caractérisation de matériaux nanocomposites à matrice polysiloxane." Lorient, 2005. http://www.theses.fr/2005LORIS048.
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Masai, Hirokazu. "Studies on the organically-modified polysiloxane low-melting glasses." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144529.
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Supian, Faridah Lisa. "Sensing interactions within nanoscale calixarene and polysiloxane Langmuir-Blodgett films." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538002.
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Majid, Wan Haliza Abd. "Pyroelectric activity in cyclic and linear polysiloxane Langmuir-Blodgett films." Thesis, University of Sheffield, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320062.
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Feng, Linqian. "Synthesis and Characterization of Polyimide Copolymers Containing Ladder-Like Polysiloxane." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406819476.
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Lee, Kyoungmi. "DEVELOPMENT OF PROTEIN-IMPRINTED POLYSILOXANE BIOMATERIALS: PROTEIN SELECTIVITY AND CELLULAR RESPONSES." Lexington, Ky. : [University of Kentucky Libraries], 2005. http://lib.uky.edu/ETD/ukybien2005t00373/Thesis.pdf.
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Thesis (M.S.)--University of Kentucky, 2005.Title from document title page (viewed on January 19, 2006). Document formatted into pages; contains: viii, 59 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 53-58).
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Dalgakiran, Sibel. "Design and electrochemical characterizaton of novel functionalized polythiophene and polysiloxane derivatives." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42226.
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Metal-containing conducting polymers are a new and interesting class of materials that
combine some of the redox properties of the conducting polymers and metal ions. In metal-containing
conjugated polymers, there are several possible arrangements of the metal group
relative to the backbone. This research focuses on the development of novel thiophene
derivatives, with various side groups using different synthetic approaches and electrochemical
polymerization. The resulting polymers could be excellent candidates for chemical sensors, solar
cells, photoactive molecular devices and capacitors.
Thiophene-based polymers containing η⁶-(haloarene)-η⁵-cyclopentadienyliron(II)
hexafluorophosphate or ferrocene moieties were synthesized. Thiophene monomers which
contained organoiron complexes were successfully polymerized using condensation
polymerization and electropolymerization. The monomers and their precursors were
characterized through nuclear magnetic resonance spectroscopy, infrared spectroscopy, cyclic
voltammetry and electrochemical impedance spectroscopy. The thermal properties were studied
with thermogravimetric analysis and differential scanning calorimetry.
A novel series of functionalized thiophenes incorporating naphthol, coumarin and pyrene
pendants were synthesized by Steglich esterification in the presence of DCC/DMAP and the
synthesized monomers were electrochemically deposited onto glassy carbon and carbon fibre
microelectrodes as active electrode materials. Another series was prepared with thiophenes using
pendant terpyridine groups of varying functionality. The electrochemical impedance
measurements were performed on surface-modified electrodes. Variation of capacitance values
was explained according to the different fluorophore groups attached to the thiophene as well as
the different substrates. The fluorescence behaviours and the surface morphological analysis
were explained in detail.
Additionally, using organoiron-mediated nucleophilic aromatic substitution, a number of
allylamine-containing organoiron complexes were prepared. These materials were further
hydrosilated with methyldiethoxyhydrosilane to generate cationic organoiron siloxanes and
ferrocene-containing siloxane complexes. In situ cleavage of the ethoxy groups followed by the
addition of H₂SO₄ resulted in the formation of polymeric materials. The synthesized polymers
were individually blended with PAN/DMF matrix to form composite thin films. The films
indicated porous surface morphology, increasing the surface activity.
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Holder, Simon James. "The synthesis and evaluation of cyclic and linear polysiloxane Langmuir-Blodgett materials." Thesis, University of Hull, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318703.
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McAfee, LaRuth C. (LaRuth CaSandra). "Polysiloxane-based liquid crystal block copolymers for piezoelectric and mechano-optical applications." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32321.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2005.Includes bibliographical references.
Liquid crystal research has gained interest in a wide range of applications that go beyond displays. Some of these applications include memory devices, sensors, and variable light valves. Currently, liquid crystals in the form of small molecules are capable of exhibiting fast response times; however, there are many advantages to using block copolymers in these applications, such as the surface stabilization caused by the block copolymer morphology, and recent research has increased in the area of LC block copolymers. In this group, LC block copolymer research has focused on diblock copolymers with one amorphous block and one side-chain LC block, and examined fundamental phase behavior of these complex systems, and the interplay between liquid crystal and block copolymer ordering. This research seeks to examine the potential use of ferroelectric and nematic LC block copolymer elastomers as actuators. These devices can be used as artificial muscles, in microrobotics, in micromachinery, in MEMS, and in other applications that require gates or valves. Artificial muscles have previously been prepared using multilayer composites of conducting polymers and non-conducting materials that may or may not be polymers. Similar functionality could also be accomplished by preparing an amorphous-LC block copolymer with cylindrical morphology. The proposed polymers for this research offer unique processing, mechanical, and electrical advantages over the current technologies because they are both block copolymers and elastomers.
(cont.) The main issues that need to be examined when designing such a material are the response time after an electrical pulse has been applied, the amount of strain achievable, and, if used in biological applications, the biocompatibility of the materials. This project specifically studies the first two issues. In order to do this, block copolymers with side-chain liquid crystal mesogens have been synthesized and their properties are currently being studied. Initially, a polystyrene-b-polyvinylmethylsiloxane diblock copolymer backbone with side-chain LC mesogens was studied. Diblock studies are useful as model systems and have potential for electro-optic applications. However, studies on PS-b-PVMS-b-PS triblock copolymers allow us to make a true elastomer. The mesogens were chosen such that the nematic or smectic C* phase will be present at the desired operating temperature and electromechanical actuation can be obtained. Mesogens were attached to homopolymer and BCP backbones. DSC indicated that there was phase mixing in all BCP samples because the PS ... is lowered or absent upon attachment of the mesogen. Nematic mesogens with long alkyl spacers exhibited significant phase mixing and no PS ... unless the polymer backbone was initially more than 50wt% PS. SAXS data showed strong smectic LC order (...), but weak (...) or no BCP order in films at room temperature. TEM and AFM indicated poorly ordered segregated morphologies in samples, which agreed well with the SAXS data. Mesogens with short spacers strengthened BCP phase segregation, as indicated by well-defined block copolymer peaks in SAXS and well-defined interfaces in TEM images.
(cont.) At room temperature, some samples did not exhibit liquid crystalline textures or birefringence until sheared or stretched when viewed in the polarized optical microscope, indicating mechano-optical properties. Initial attempts to orient the liquid crystal mesogens have been successful using mechanical stretching in the DMA. Also, a new setup has been developed and preliminary studies have begun to measure the electromechanical properties of these materials.
by LaRuth C. McAfee.
Ph.D.
31
Sung, Cynthia. "A study of polyethylene oxide-polysiloxane networks as biomaterials for drug release." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14501.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Harvard-MIT Division of Health Sciences and Technology Program in Medical Engineering and Medical Physics, 1989.Includes bibliographical references.
by Cynthia Sung.
Ph.D.
32
SABA, AHMED. "Sur la tenue dielectrique aux temps courts de couches minces de polysiloxane." Toulouse 3, 1989. http://www.theses.fr/1989TOU30082.
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Le travail presente concerne l'etude du phenomene de rupture dielectrique a court terme dans des couches minces de polysiloxane elaborees par polymerisation en phase gazeuse. L'utilisation de strcutures dites autocicatrisantes metal-polymere-metal permet de collecter un grand nombre de donnees sur le meme echantillon. L'application du modele statistique de weibull generalise a la distribution des tensions de rupture lorsque les echantillons sont soumis a des rampes de tension permet la definition du champ nominal go et du champ de seuil gs. Dans le cas de creneaux de tension, le traitement statistique des temps de retard et l'etude de leur dependance en fonction du champ conduit a la determination du champ de rupture specifique gc. Ces divers criteres (go, gs, gc) ont ete utilises afin d'etudier l'influence de la temperature de recuit des couches sur leur tenue dielectrique. Le point majeur de l'etude concerne la question de l'independance statistique des donnees collectees au cours de l'application d'une sollicitation electrique stationnaire. Dans le cas d'echantillons de polysiloxane et a la temperature ambiante, les claquages ne sont jamais distribues aleatoirement dans le temps. L'auteur a effectivement mis en evidence l'existence d'une population de claquages a caracteristiques particulieres, dite population de points faibles. Les effets de charge d'espace entrainent d'autre part, une diminution de la probabilite de claquages dans le temps. Finalement, l'auteur donne une interpretation sur l'origine du mecanisme de rupture dielectrique des couches minces de polysiloxane qui est d'origine thermique impulsionnel
33
Loftus, Lauren M. "An AFM Study of Photoaddressable Topography in Ruthenium Sulfoxide-Doped Polysiloxane Copolymers." Ohio University Art and Sciences Honors Theses / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ouashonors1399042949.
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LALAM, NAWEL. "Synthese d'une nouvelle famille de polymeres azomethine-polysiloxane. Etude de leur cyclisation." Paris 6, 2001. http://www.theses.fr/2001PA066322.
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Nos travaux ont consiste en la synthese d'une nouvelle famille de macrocycles azomethine-siloxane par cyclisation de leurs polymeres lineaires respectifs. Ces polymeres sont obtenus par reaction de polyhydrosilylation de precurseurs azomethine. La premiere partie de notre memoire a ete consacree a la synthese de monomeres reactifs ,-diallyloxy presentant sur leur noyau central un chainon alkoxy comportant 2 a 6 carbones. Leur etude thermique a montre qu'ils etaient tous thermotropes et qu'ils developpaient des mesophases nematiques. Dans la deuxieme partie de nos travaux, la reaction de polyhydrosilylation realisee entre les precurseurs ,-diallyloxy susynthetises et le 1,1,3,3,5,5-hexamethyltrisiloxane a ete etudiee. Elle a conduit a des oligomeres qui presentent une stabilite thermique et chimique faible et ne presentent aucun caractere cristal liquide. Enfin, dans la derniere etape de notre etude, nous avons etudie la cyclisation de tous les polymeres et montre qu'elle etait possible quelle que soit la longueur du greffon alkoxy. Le macrocycle dimere aux chainons diethoxy (note coc 2) a pu etre isole par precipitation. Celui-ci est thermotrope et developpe une structure nematique. Les autres macrocycles, possedant des chainons alkoxy plus longs, presentait une solubilite equivalente aux polymeres lineaires correspondants ce qui empeche leur separation. Une etude structurale complete de tous les composes synthetises (monomeres, modeles moleculaires, polymeres et dimere cyclique) a ete effectuee par rmn 1h et 1 3c. De plus, la spectrometrie de masse maldi-tof a ete un outil indispensable pour s'assurer de la structure exacte du dimere cyclique coc 2. Par notre travail, nous avons apporte une contribution a l'etude du phenomene de cyclisation et avons montre que la synthese de dimeres cycliques possedant des substituants alkoxy comportant 2 a 6 carbones etait possible.
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Kiefer, Laura A. "Synthesis and characterizaton of novel polyester/polysiloxane and polyester/arylphosphine oxide copolymers." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-07122007-103944/.
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Ciobotarescu, Simona. "Synthesis, molecular modeling and photochromic behaviour of polysiloxanes containing azo-groups with different geometries." Thesis, Angers, 2020. http://bu.univ-angers.fr/Contact.
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La présente thèse représente une étude complexe des azopolysiloxanes photosensibles et rejoint les techniques théoriques et expérimentales. Le thème tourne autour du phénomène de transport de masse des azopolymères induit par la photoisomérisation des azobenzènes. La conversion transt – cis de l'azobenzène et de ses dérivés est un processus réversible actionné par la lumière, qui permet le réarrangement de la matière environnante au niveau nano et micro. Cette propriété est exploitée pour fabriquer des réseaux de relief de surface (SRG) avec caractéristiques géométriques specifiques. Les présentes études visent à comprendre ce mécanisme complexe, sujet à une grande controverse parmi les différents groupes de recherche. Les paramètres qui contrôlent le processus sont traités et analysés. L'étude expérimentale comprend la synthèse et la caractérisation de quatre azopolysiloxanes qui sont ensuite analysés pour leur capacité d'obtenir des SRG. Le comportement photochromique est évalué par des expériments d'irradiation à différentes intensités lumineuses, en présence ou l'absence d'une lumière d'assistance qui devrait intensifier l'isomérisation. La simulation informatique se concentre sur la diffusion des molécules dans le système: une molécule de type azobenzène (moteur moléculaire) diluée dans le milieu hôte. Des calculs de modélisation moléculaire sont effectués pour des moteurs de différentes longueurs et avec différents temps d'isomérisation (isomérisation rapide ou lente) afin de définir la relation entre ces paramètres et la diffusion. Fournir des informations expérimentales et théoriques sur les azopolymères, est trop important pour comprendre la formation de SRGThe herein thesis represents a complex study of photosensitive azopolysiloxanes and rejoins both theoretical and experimental techniques. The theme revolves around the azopolymer’s mass transport phenomenon induced by the photoisomerization of azobenzenes. Trans- to cis conversion of azobenzene and its derivatives is a reversible light actuated process that enables the rearrangement of surrounding matter at nano and micro level. This property is exploited to fabricate surface relief gratings (SRG) with certain geometrical features. The present studies are directed to comprehension of this complex mechanism, subject to great controversial among different research groups. The parameters that control the process are addressed and analyzed. Experimental study comprises the synthesis and characterization of four azopolysiloxanes which are then analyzed for the capacity to obtain SRG. Photochromic behaviour is evaluated through irradiation experiments at different light intensity, in the presence or absence of an assistance light that supposedly intensifies isomerization. Computer simulation focuses on diffusion of the molecules in the system: one azobenzene – like molecule (molecular motor) diluted in the host medium. Molecular modeling calculations are performed for motors with different lengths and with various isomerization times (fast or slow isomerization) in order to define the relation between these parameters and diffusion. Providing experimental and theoretical info on azopolymers is part of the SRG formation insight
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PERES, RICHARD. "Synthese et caracterisation de copolymeres thermotropes lineaires de type polyimine aromatique-bloc-polysiloxane." Paris 6, 1990. http://www.theses.fr/1990PA066269.
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L'essentiel de ce travail concerne la synthese de nouveaux copolymeres thermotropes lineaires de type polyimine aromatique-bloc-polysiloxane. Deux procedes de synthese ont ete mis au point et optimises, la polyhydrosilylation et la polyimination. Leur caracterisation a d'abord fait l'objet d'une analyse structurale complete. Leur polymorphisme a ete mis en evidence par dsc, observations au microscope polarisant et diffraction x. Dans le cadre de cette etude, nous avons mis en evidence l'influence: 1) de la masse moleculaire, 2) de la longueur et de la polymolecularite de la sequence siloxane, 3) de la nature de la structure mesogene sur le comportement thermotrope des polymeres. Par ailleurs, nous avons montre qu'au cours de leur synthese, des macrocycles thermotropes pouvaient se former. Leur formation s'opere par interimination en solution a partir des chaines polymeres. Differents macrocycles ont ete isoles et caracterises. Leur caractere thermotropes a ete etabli par dsc, microscopie polarisante et diffraction x
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Nelson, Tiffany S. "Synthesis and Characterization of Crosslinked Polysiloxane-Clay Nanocomposites for Uses in Skin Care Products." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1154620091.
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Vadala, Michael Lawrence. "Preparation and Functionalization of Macromolecule-Metal and Metal Oxide Nanocomplexes for Biomedical Applications." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27098.
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Copolymer-cobalt complexes have been formed by thermolysis of dicobalt octacarbonyl in solutions of copolysiloxanes. The copolysiloxane-cobalt complexes formed from toluene solutions of PDMS-b-[PMVS-co-PMTMS] block copolymers were annealed at 600-700 °C under nitrogen to form protective siliceous shells around the nanoparticles. Magnetic measurements after aging for several months in both air and in water suggest that the ceramic coatings do protect the cobalt against oxidation. However, after mechanical grinding, oxidation occurs. The specific saturation magnetization of the siliceous-cobalt nanoparticles increased substantially as a function of annealing temperature, and they have high magnetic moments for particles of this size of 60 emu g-1 Co after heat-treatment at temperatures above 600 °C. The siliceous-cobalt nanoparticles can be re-functionalized with aminopropyltrimethoxysilane by condensing the coupling agent onto the nanoparticle surfaces in anhydrous, refluxing toluene. The concentration of primary amine obtained on the surfaces is in reasonable agreement with the charged concentrations. The surface amine groups can initiate L-lactide and the biodegradable polymer, poly(L-lactide), can be polymerized directly from the surface. The protected cobalt surface can also be re-functionalized with poly(dimethylsiloxane) and poly(ethylene oxide-co-propylene oxide) providing increased versatility for reacting polymers and functional groups onto the siliceous-cobalt nanoparticles.Phthalonitrile containing graft copolysiloxanes were synthesized and investigated as enhanced oxygen impermeable shell precursors for cobalt nanoparticles. The siloxane provided a silica precursor whereas the phthalonitrile provided a graphitic precursor. After pyrolysis, the surfaces were silicon rich and the complexes exhibited a substantial increase in Ms. Early aging data suggests that these complexes are oxidatively stable in air after mechanical grinding. Aqueous dispersions of macromolecule-magnetite complexes are desirable for biomedical applications. A series of vinylsilylpropanol initiators, where the vinyl groups vary from one to three, were prepared and utilized for the synthesis of heterobifunctional poly(ethylene oxide) oligomers with a free hydroxy group on one end and one to three vinylsilyl groups on the other end. The oligomers were further modified with carboxylic acids via ene-thiol addition reactions while preserving the hydroxyl functionality at the opposite terminus. The resulting carboxylic acid heterobifunctional PEO are currently being investigated as possible dispersion stabilizers for magnetite in aqueous media.Ph. D.
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Vadala, Michael Lawrence. "Complexation of Block Copolysiloxanes with Cobalt Nanoparticles." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31841.
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Poly(dimethylsiloxane-b-methylvinylsiloxane) (PDMS-b-PMVS) diblock copolymers were synthesized via anionic living polymerization with controlled molecular weights and narrow molecular weight distributions. Targeted molecular weights agreed well with experimental values determined by 1H NMR, 29Si NMR, and GPC. Morphologies were investigated by DSC to analyze glass transition temperatures. Only one Tg was observed for each PDMS-b-PMVS block copolymer suggesting that the blocks were miscible in bulk. Tg¡¯s ranged from approximately -126 to -128 ¡ãC and were between the Tg¡¯s of the PDMS (-123 ¡ãC) and PMVS (-137 ¡ãC) homopolymers.
The PMVS blocks were functionalized with trimethoxysilethyl or triethoxysilethyl pendent groups via hydrosilations to yield poly(dimethylsiloxane-b-[poly(methylvinyl)-co-(methyl-(2-trimethoxysilethyl)siloxane)] (PDMS-b-[PMVS-co-PMTMS]) or poly(dimethylsiloxane-b-[poly(methylvinyl)-co-(methyl-(2-triethoxysilethyl)siloxane)] (PDMS-b-[PMVS-co-PMTES]) copolymers, respectively. The PMVS blocks were either derivatized with the functional groups or half of the repeat units were functionalized. The fully hydrosilated materials were diblock copolymers, and the materials that were 50% hydrosilated had a random sequence of methylvinylsiloxy units and methyl-(trialkoxysilethyl)siloxy units. The PDMS-b-[PMVS-co-PMTES] block copolymers had Tg¡¯s ranging from -124 to -126 ¡ãC and only one Tg was observed. Surface tension measurements suggested that PDMS-b-[PMVS-co-PMTES] copolymers formed aggregates in toluene.
Stable suspensions of superparamagnetic cobalt nanoparticles were prepared in toluene in the presence of PDMS-b-[PMVS-co-PMTMS] or PDMS-b-[PMVS-co-PMTES] copolymers via thermolysis of Co2(CO)8. It is hypothesized that the block copolymers functioned as micellar templates for the cobalt nanoparticles. TEM micrographs showed non-aggregated cobalt nanoparticles coated with copolymers that had mean particle diameters ranging from ¡à 10-15 nm. Specific saturation magnetizations of these cobalt-copolymer complexes ranged from 90-110 emu g-1 Co, comparable to literature values for this particle size.Master of Science
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Ragheb, Ragy. "Synthesis and Characterization of Polylactide-siloxane Block Copolymers as Magnetite Nanoparticle Dispersion Stabilizers." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/31687.
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Polylactide-siloxane triblock copolymers with pendent carboxylic acid functional groups have been designed and synthesized for study as magnetite nanoparticle dispersion stabilizers. Magnetic nanoparticles are of interest in a variety of biomedical applications, including magnetic field-directed drug delivery and magnetic cell separations. Small magnetite nanoparticles are desirable due to their established biocompatibility and superparamagnetic (lack of magnetic hysteresis) behavior. For in-vivo applications it is important that the magnetic material be coated with biocompatible organic materials to afford dispersion characteristics or to further modify the surfaces of the complexes with biospecific moieties.
The synthesis of the triblock copolymers is comprised of three reactions. Difunctional, controlled molecular weight polymethylvinylsiloxane oligomers with either aminopropyl or hydroxybutyl endgroups were prepared in ring-opening redistribution reactions. These oligomers were utilized as macroinitiators for ring-opening L-lactide to provide triblock materials with polymethylvinylsiloxane central blocks and poly(L-lactide) endblocks. The molecular weights of the poly(L-lactide) endblocks were controlled by the mass of L-lactide relative to the moles of macroinitiator. The vinyl groups on the polysiloxane center block were further functionalized with carboxylic acid groups by adding mercaptoacetic acid across the pendent double bonds in an ene-thiol free radical reaction. The carboxylic acid functional siloxane central block was designed to bind to the surfaces of magnetite nanoparticles, while the poly(L-lactide)s served as tailblocks to provide dispersion stabilization in solvents for the poly(L-lactide). The copolymers were complexed with magnetite nanoparticles by electrostatic adsorption of the carboxylates onto the iron oxide surfaces and these complexes were dispersible in dichloromethane. The poly(L-lactide) tailblocks extended into the dichloromethane and provided steric repulsion between the magnetite-polymer complexes.
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Klonczynski, Alexander [Verfasser]. "Herstellung und Charakterisierung hochtemperaturstabiler Si(B)OC Keramiken auf Basis kommerzieller Polysiloxane / Alexander Klonczynski." Aachen : Shaker, 2007. http://d-nb.info/1164341464/34.
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Montalan, Dominique. "Etude in-situ des propriétés électriques des films de polysiloxane déposés par plasma froid." Toulouse 3, 1986. http://www.theses.fr/1986TOU30015.
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Reiller, Catherine. "Synthèse, caractérisation et propriétés de copolymères érodables polysiloxane-poly(acide lactique) à hydrophile contrôlée." Paris 13, 1998. http://www.theses.fr/1998PA132003.
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Des copolymeres greffes polysiloxane-g-poly(acide l-lactique) dont le tronc polysiloxane porte des fonctions arylsulfonate, destinees a rendre le materiau plus hydrophile et donc plus sensible a la degradation hydrolytique, ont ete synthetises et compares a des copolymeres triblocs plla-b-pdms-b-plla et multiblocs (plla-pdms)#n precedemment etudies au laboratoire. La synthese est realisee a partir d'un poly(hydrogenomethylsiloxane-co-dimethylsiloxane) a extremites bloquees, obtenu par polymerisation cationique de d#4 et de d#h#4 en presence d'hexamethyldisiloxane. L'hydrosilylation de l'allylglycidylether par ce copolymere conduit a un polysiloxane epoxyde dont les fonctions epoxyde peuvent ensuite etre ouvertes par l'hydroxybenzene sulfonate de sodium, mais l'amine catalysant la reaction provoque des coupures de chaine. La derniere etape consiste a greffer du poly(acide l-lactique) sur ce polysiloxane fonctionnalise. On peut soit amorcer la polymerisation du l-lactide par les fonctions alcool secondaire resultant de l'ouverture des fonctions epoxyde, soit faire reagir sur les fonctions epoxyde un poly(acide l-lactique) a extremites acide carboxylique et alcool obtenu par polycondensation de l'acide l-lactique. Cette deuxieme voie presente plusieurs avantages. Ces copolymeres greffes presentent une aptitude a la cristallisation et a la formation de stereocomplexe (par melange avec du pdla) comparable a celle des copolymeres triblocs et meilleure que celle des copolymeres multiblocs. Leur sensibilite a l'hydrolyse est 1000 fois superieure a celle des copolymeres triblocs a ph = 13 et n'est diminuee que d'un facteur 8 par la stereocomplexation. L'introduction de groupements arylsulfonate apparait donc comme un moyen efficace de moduler la degradabilite hydrolytique sans trop perturber les proprietes thermiques. Inversement, la stereocomplexation permet de moduler les proprietes thermomecaniques sans trop diminuer la degradabilite.
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Martin, Julie. "Design and direct synthesis of peptide-branched polysiloxane. Towards new generation of hybrid biomaterials." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS093.
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Les travaux de recherches de cette thèse concernent la conception et la synthèse de nouveaux matériaux hybrides basés sur un squelette polysiloxane. Pour cela, plusieurs molécules ont été silylées dans le but d’être incorporées dans une chaine de silicone multifonctionnel. En effet, au contraire des approches de post-greffages, nous avons mis au point une copolymérisation directe de ces macromonomères hybrides présentant une fonction methyldihydroxysilane avec du dichlorodimethylsilane (DCDMS). Plusieurs types de biomolécules ont été silylées : peptides, médicaments, sondes pour l’imagerie, chacune de ces molécules apportant des propriétés particulières au matériau final. Trois principales applications sont présentées : (i) la synthèse directe de film de silicone réticulés bioactifs, (ii) la préparation de nanoparticules (NPs) de silicone multifunctionnel (iii) ou des polyplexes. Des films de PDMS bioactifs (antibactériens ou promouvant l’adhésion cellulaire) réticulés ont été obtenus par copolymérisation de macromonomères hybrides peptidiques avec du DCMS et des monomères silane ou vinyl silane permettant une réticulation par hydrosilylation. Les NPs de silicone hybride sont issues de l’introduction de plusieurs macromonomères hydrophiles de 0.5 à 1mol% par rapport au DCDMS. Des ligands peptidiques ciblant les cellules cancéreuses, du PEG et du méthotrexate, tous trois silylés, ont été préparés et copolymérisés. Enfin, nous présentons les résultats préliminaires obtenus pour la préparation de polyplexes de siRNA basés sur la polymérisation in situ de peptides hybrides possédant des séquences riches en histidine et lysineThe purpose of this PhD work was the design and synthesis of new hybrid biomaterials based on a polysiloxane backbone. To do so, several biomolecules were silylated, in order to be incorporated in a multifunctional silicone backbone by a bottom-up strategy. Indeed, in contrast to post-grafting approaches, we set up the direct copolymerization of hybrid biomolecule macromonomers presenting a methyldihydroxysilyl moiety, with the dichlorodimethylsilane (DCDMS). Different types of biomolecules have been silylated: peptides, drugs and imaging probes, each of them affording specific properties to the final bioorganic silicone material. Three main applications are described: (i) the design and synthesis of bioactive PDMS cross-linked materials, (ii) silicone-based nanoparticules (NPs) and (iii) silicone-based polyplexes. PDMS materials with biological properties, either antimicrobial or cell adhesion, were obtained by copolymerization of hybrid peptide macromonomer with DCDMS, vinyl and silane reagents followed by hydrosilylation. Silicone-based NPs resulted from the introduction of several hydrophilic macromonomers at 0.5 to 1 mol% compared to DCDMS. Hybrid peptide ligands targeting cancer cell receptors, PEG and a drug model (Methotrexate) were prepared and copolymerized. At last, we investigated the preparation of siRNA polyplexes involving LysHis-based hybrid peptide macromonomers by an in situ polymerization method
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Beouch, Layla. "Synthèse et étude des propriétés de surface de copolymères alternés polysiloxane / bisphénol A modifiés." Cergy-Pontoise, 2002. http://www.theses.fr/2002CERG0152.
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La synthèse de copolymères organosiliciés ayant des motifs bisphénol A régulièrement répartis le long de la chaîne et porteurs de fonctions réactives a été réalisée selon différentes méthodes. La polycondensation par hydrosilylation à partir du 2,2'-diallylbisphénol A (dBPA) et d'oligosiloxanes ,-(diSiH) de masses molaires variables suivie de modifications chimiques des groupes phénol a tout d'abord été examinée. La cinétique de la réaction d'hydrosilylation a été étudiée par RMN 1H. La principale réaction secondaire est l'isomérisation des fonctions allyle en fonctions propényle qui ne peuvent être hydrosilylées, ce qui provoque un arrêt de la croissance des chaînes Les autres réactions secondaires telles que l'O-silylation et l'addition n'ont pas été détectées. Les modifications chimiques des fonctions OH du BPA ont ensuite été effectuées par réactions de substitution nucléophile ou d'estérification. Des polycondensats portant des greffons terminés par des groupements Br, époxyde, allyle, alcool aliphatique, polyoxyde d'éthylène, acide carboxylique et imide ont été préparés. D'autre part, la fonctionnalisation par un groupement amorceur de polymérisation radicalaire contrôlée (ATRP) a permis le greffage de divers types de polymères méthacryliques sur ces copolymères modifiés. Une autre stratégie qui consiste à modifier le dBPA avant d'effectuer la polycondensation par hydrosilylation donne des copolymères parfaitement définis, sans motifs BPA résiduels. L'ensemble de ces polymères a été caractérisé par RMN 1H, IR, SEC etDSC. Les propriétés de surface de certains de ces copolymères ont ensuite été étudiées par la technique de Langmuir-Blodgett (LB). Les résultats indiquent que quelques couches de polymère suffisent à rendre hydrophobes la plupart des substrats étudiés. L'étude de la tension de surface des dépôts en fonction de la nature des greffons ainsi que l'examen de la stabilité des dépôts au cours du temps montrent qu'il est préférable d'utiliser des chaînes siloxane courtes dans ces copolymères. Ces copolymères alternés, synthétisés pour la première fois, possèdent une structure soigneusement contrôlée et des propriétés modulables. De telles structures pourraient conduire à des applications comme promoteurs d'adhésion ou en cosmétologieOrganosilicon based copolymers with reactive groups were prepared by polycondensation using hydrosilylation of 2,2'diallylBPA (dBPA) with hydride terminated polydimethylsiloxanes of various lengths, followed by chemical modifications of the phenol groups. Isomerization of the allyl groups into propenyl groups acting as limiting agents (because they cannot undergo hydrosilylation), is the major side reaction which occurs during hydrosilylation, as shown by 1H NMR. Nucleophilic substitution as well as esterification reactions on the OH groups of BPA moieties lead to polycondensates bearing grafts with Br, epoxy, allyl, aliphatic OH, polyethylene oxide, carboxylic acid, and imide end groups. The same polymers were obtained by hydrosilylation of appropriately modified dBPA precursors with hydride terminated polysiloxanes leading to well-defined copolymers without remaining unmodified BPA groups. Moreover, functionalization of the OH groups of BPA units by an ATRP initiator allows the grafting of several polymethacrylates from the polysiloxane backbone. All these polymers were characterized by 1H NMR, FTIR, SEC, and DSC. Surface properties of some of those copolymers were studied according to the Langmuir Blodgett technique. Only a few polymer layers are enough to make most of the substrates hydrophobic. Surface tension measurements of modified substrates according to graft nature as well as studies of the stability of such layers with time showed that the best results are obtained with short polysiloxane segments in the main chain. Such new alternating copolymers having a well-defined structure and the properties of which can be tuned, could find adhesive and personal care applications
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DeClue, Michael Scott. "Functionalized polymers : synthesis of photorefractive polymers and solid phase asymmetric dihydroxylation ligands on polysiloxane /." Diss., Connect to a 24 p. preview or request complete full text in PDF formate. Access restricted to UC campuses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3071006.
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Wang, Shanshan. "Development of solid polymer electrolytes of polyurethane and polyether-modified polysiloxane blends with lithium salts." Akron, OH : University of Akron, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1196139638.
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Dissertation (Ph. D.)--University of Akron, Dept. of Polymer Engineering, 2007."December, 2007." Title from electronic dissertation title page (viewed 01/30/2008) Advisor, Kyonsuku Min; Committee members, Mark Soucek, Kevin A. Cavicchi, Gary R. Hamed, Michael H. Cheung; Department Chair, Sadhan C. Jana; Dean of the College, Stephen Z. D. Cheng; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Seyfried, Mona [Verfasser], and Gerhard [Akademischer Betreuer] Sextl. "Neuartige Sulfonsäure-funktionalisierte Polysiloxane für die Anwendung als selbstätzendes Dentaladhäsiv / Mona Seyfried. Betreuer: Gerhard Sextl." Würzburg : Universitätsbibliothek der Universität Würzburg, 2013. http://d-nb.info/1030475512/34.
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Chou, H. L., and 周惠隆. "Polysiloxane Modified Epoxy." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/25731625923277916931.
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碩士義守大學
材料科學與工程學系
87
Encapsulation is one of the important steps in IC packaging processes. The yield is highly affected by the residual stress in the packages, which results from the chemical shrinkage due to crosslinking and physical shrinkage during cooling. In this work, a low stress matrix resin is synthesized by adding dimethylvinyl polysiloxane into the o-cresol-formaldehyde novolac epoxy resin (CNE) to form a simultaneous interpenetrating network (SIN). The rate of reaction of CNE is controlled by varying the amount of triphenyl phosphine (TPP), and that of polysiloxane controlled by using the cross-linking agent of dicumyl peroxide. The effects of TPP and DCP in each system can be obtained from the relation between heat of reaction and glass transition temperature, Tg. Differential scanning calorimetry is employed to investigate the reaction kinetics, which reveal that the Arrhenius and Kamal’s reaction schemes successfully model the polysiloxane and epoxy systems, respectively. The prepolymers are prepared according to the kinetic calculations. The method of synthesis can be either through direct blending or through a grafting reaction. The mechanical properties of CNE, SIN, and both CNE and SIN with silica filler are tested. As compared with CNE, the SIN has lower Young’s modulus and tensile strength, and the CNE with silica filler has slightly higher values of both properties. It has observed that, for the CNE with silica filler after having been formed as SIN, its modulus and tensile strength are lowered, and its strain at break increased. Tests of dynamic mechanical properties have been conducted to establish the relationship between storage modulus and temperature, and found that the storage modulus of CNE is lowered after forming into SIN. A thermal gravimetric analyzer is utilized to study properties of coefficient of thermal expansion above or below Tg of various epoxy resins with and without silica filler, which enables us to gain insight into the behaviors of cross-liking shrinkage during encapsulation. Tests of moisture absorption are conducted to study the effects of Tg and SIN on the moisture absorptivity. Measurements of viscosity are made to assist in predicting optimal encapsulation temperature and filling time. As for resistance of flammability, the SIN made exhibits higher pyrolysis temperature without gain of its residual weight. Facing ever-stringent requirements of IC encapsulation it has been found that the polysiloxane-CNE SIN is a promising encapsulant.