Dissertationen zum Thema „Polymers based materials“
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Sakahara, Rogério Massanori. „Estudo da formação da fase cristalina beta nos compósitos de polipropileno contendo anidrido maléico e carbono de cálcio“. Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-04072013-153850/.
This study aimed at improving the comprehension of the influence of calcium carbonate (CaCO3) in the formation of the beta crystalline phase of polypropylene (PP), as well as the changes in the mechanical properties of this polymer. A preliminary analysis of the grafting of the maleic anhydride in the polypropylene was carried out in order to produce specimens for the study, owing to the fact that this grafted polypropylene (PP-g-MA) contributes substantially to change the polarity of the polymer and therefore, enhance the superficial adhesion between PP and CaCO3. Two grafting methods using organic peroxide were studied. The grafted copolymers were analyzed by DSC, TGA, SEM, EDS, and FTIR. Two series of PP composites containing CaCO3 were produced by intensive melt mixing (Drais mixer), one of them having MA-g-PP. Four types of CaCO3 were used, which diameters were 0.9 µm, 2.5 µm and 3 µm, though the CaCO3 0.9 µm was surface-treated and non-treated. The concentration of CaCO3 was maintained at 5% and PP-g-MA at 5 % also, when present. The composites were tested for tensile strength, flexural modulus and impact strength (at two temperatures). Samples containing smaller particle sized CaCO3 and PP-g-MA showed synergistic improvement in the mechanical strength, and increases in the impact resistance and flexural strength were observed. Analysis of the beta crystal phase in these samples was performed using DSC and x-ray diffractometry. The influence of superficial adhesion between CaCO3 and PP was also analyzed, higher concentration of the beta crystalline phase was observed for better surface adhesion and smaller CaCO3 particle size, which contributed to the synergy between all the mechanical properties evaluated in this work.
Deans, Taneisha. „Using Nature as a way to Flame Retard Synthetic Materials“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case149154227971565.
Brenn, William Alexander. „Stimuli-responsive Materials From Thiol-based Networks“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case149192088155293.
Fan, Weizheng. „Development of Photoresponsive Polymers and Polymer/Inorganic Composite Materials Based on the Coumarin Chromophore“. University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1366903513.
Tangvijitsakul, Pattarasai. „Methoxy Poly (Ethylene Glycol) Methacrylate- Based Copolymers on the Applications of Concrete Admixtures, Mesoporous Materials, and Rheology Modifiers“. University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1442440564.
Beltran, Osuna Angela Aurora. „Evaluation of Antifouling Materials Based on Silica Gels“. University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1323359814.
Luo, Yun. „Lanthanide-based coodination polymers : new ligands for new materials ?“ Rennes, INSA, 2012. http://www.theses.fr/2012ISAR0004.
This doctoral subject aims to synthesize and characterize new porous or luminescent coordination polymers based on lanthanides ions. There are two kinds of samples used in this work : single crystals and microcrystalline powders. The former ones are synthesized for structural analysis on the basis of X-ray diffraction data. The later ones characterized by X-ray powder diffraction (XRPD) are prepared for analyzing thermal stability, luminescence properties and porosity. In this work, five systems were explored involving five multi-carboxylate ligands: H2ATPT (2-aminoterephthalic acid), H2AIP (5-aminoisophthalic acid), H2OBA (4,4’-oxybis(benzoates) acid), H4BTEC (1,2,4,5-benzenetetracarboxylic acid) and H2BPDC (4,4’-biphenyldicarboxylic acid). As a result, 15 series of single crystals were obtained by slow diffusions in U-shaped tubes through physical or chemical gels, by slow diffusions in H-shaped tubes through distilled water or by evaporation of the filtrate obtained after the synthesis of the microcrystalline powders. The microcrystalline powders were synthesized at 2°C, room temperature, 40°C and 90°C. All the powders were classified in different families according to their XRPD diagrams. Their thermal stabilities were evaluated by thermo-gravimetric analysis (TGA) and temperature depending X-ray diffraction (TDXD). Their luminescent properties were studied by solid-state luminescent measurements. Their porosities were estimated by a computational method developed in our laboratory
Phillips, Daniel J. „Biochemically adaptive materials based on (iso)thermally-responsive polymers“. Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/67603/.
Modi, Sunny J. „A novel use of bio-based natural fibers, polymers, and rubbers for composite materials“. The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1403205265.
Eder, Grace M. „Dye Molecule-Based Porous Organic Materials“. The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1530012900215452.
Yue, Kan. „Design, Synthesis and Self-Assembly of Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxane-Polymer Conjugates“. University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1384817970.
Bo, Ni. „Design, Synthesis and Self-assembly of Polyhedral Oligomeric Silsesquioxane (POSS) Based Hybrid Materials“. University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron152130982499385.
Miranda, Michael Angelo. „Bio Based Active Barrier Materials and Package Development“. University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1483450387453053.
Wang, Liang. „Aerogels based on biodegradable polymers and clay“. Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/336971.
En esta Tesis se han preparado diversos aerogeles usando polímeros biodegradables como matriz y arcilla como refuerzo, a través de un proceso de fabricación amigable con el medio ambiente. Los polímeros empleados han sido tanto de origen natural (goma árabiga, agar-agar, goma xantana, almidón) o sintéticos como la carboximetilcelulosa (CMC) o el alcohol polivinílico. Los compuestos formados se han caracterizado a través de diferentes técnicas con el objeto de relacionar las morfologías generadas con las propiedades térmicas y mecánicas resultantes. La gran mayoría de los aerogeles polímero/arcilla exhiben una estructura porosa y laminar que se forma a raíz de la liofilización. Sin embargo, se ha apreciado que altas viscosidades en la solución precursora puede romper la arquitectura laminar al retardar el crecimiento de los cristales de hielo (ej. Solución acuosa de 2.5 % peso de agar). La estructura y las propiedades de los aerogeles están asimismo y en general influenciados por la relación polímero/arcilla. En estos sistemas, las moléculas de polímero actúan a manera de pegamento uniendo las partículas de arcilla, incrementando de esa manera notablemente la capacidad mecánica de los aerogeles. Por otro lado la arcilla actúa entre otras formas, como barrera térmica incrementando la resistencia térmica y al fuego de las espumas formadas. Dentro de este trabajo se han empleado fibras de celulosa recicladas de residuos de papel en un intento de preparar bio-aerogeles a partir de material de desecho. La unión de estas fibras con CMC permitió obtener aerogeles con propiedades mejoradas y la posibilidad de emplear estos residuos en un segundo uso. Además del mezclado físico, en algunos casos se ha realizado una reacción de entrecruzamiento para ajustar las propiedades finales, como en el caso de los aerogeles goma xantana/arcilla o almidón/arcilla. La mezcla de agar con goma xantana en solución acuosa resultó en un notable aumento de propiedades con respecto a las composiciones que contenían un único polímero, debido al cambio morfológico inducido, pasando de una estructura laminar a una de tipo panal de abeja (honeycomb). De esta forma y a través de la relación entre estos dos polímeros naturales ha sido posible balancear y definir las propiedades finales deseadas para el aerogel. En los sistemas almidón/arcilla el entrecruzamiento se ha conseguido a través de un agente externo como el glutaraldehido. Atendiendo a su posible uso final, unas de las propiedades más relevantes en los aerogeles que se ha estudiado ha sido la estabilidad térmica y la resistencia al fuego. En este sentido, se han preparado sistemas basados en Polivinilalcohol/arcilla modificados con diferentes retardantes de llama. De los diversos aditivos probados la combinación con hidróxido de aluminio ha mostrado un efecto sinérgico incrementando tanto de la resistencia a fuego como las propiedades mecánicas. En los sistemas basados en celulosa la presencia de polifosfato de amonio y arcilla ha demostrado así mismo un efecto potenciador de la estabilidad térmica y en el retardo de llama.
Huang, Jiahao. „Design, Synthesis, and Self-Assembly of Nano-Sized Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxane and Perylene Bisimides“. University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1603670714151325.
Cheung, Kai-yin, und 張啓賢. „Metallopolyyne polymers based bulk heterojunction (BHJ) solar cells“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841719.
Al, Khalyfeh Khaled. „Ferrocene-Based Monomers, Oligomers and Polymers as Electro-Active Materials“. Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-216647.
Die vorliegende Doktorarbeit beschäftigt sich mit Synthese und Charakterisierung von funktionalisierten Ferrocenen mit bis zu vier Aldehyd- und Vinylgruppen und ihrer Verwendung als Monomere für neuartige ferrocenbasierte Oligomere mit konjugiertem Rückgrat unter ADMET (acyclic diene metathesis) und HWE- (Horner-Wadsworth-Emmons) Reaktionsbedingungen. Zusätzlich wurden ferrocenhaltige Polymere mit einem aliphatischen Rückgrat durch Polymerisation mit und ohne Lösemittel hergestellt und ihr elektrochemisches Verhalten untersucht. Das Hauptaugenmerk dieser Arbeit liegt in der Optimierung der elektrochemischen Eigenschaften der ferrocenbasierten Materialien (Oligomere oder Polymere) durch Variation des Polymerrückgrats, welche zahlreiche funktionelle Gruppen für die vernetzte Polymerisation und die Co-Polymerisation liefert. Durch diesen Prozess wird das molekulare Gewicht erhöht. Zusätzlich wird die Verwendung als elektroaktive Materialien insbesondere für die Energiespeichertechnik diskutiert. Durch lösungsmittelfreie Reaktionsbedingungen wurden ein hoher Monomerumsatz, relativ hohe molare Massen und zugleich längere Polymerketten erzielt. Elektrochemische Messungen (CV) zeigten, dass Ferrocenmoleküle mit mehr als zwei Formylgruppen die Elektronendichte an der Ferrocenyleinheit verringern und bei Oxidation leicht zersetzt werden. Erniedrigung der Messtemperatur und die Verwendung des nur schwach koordinierenden Leitsalzes [NnBu4][B(C6F5)4] führten zu aussagekräftigen Ergebnissen. Weiterhin konnte ein linearer Zusammenhang zwischen dem Redoxpotential und der Anzahl der Formyleinheiten aufgezeigt werden. Mutlizyklische Messungen bestätigten, dass das Ferrocen / Ferrocenium-Redoxpaar mindestens 100 Zyklen stabil ist. Mittels spektroelectrochemisches Messungen konnte gezeigt werden, dass konjungierte (oligomere) Verbindungen eine elektronische Wechselwirkung (IVCT) aufweisen, während aliphatische Rückgrade eine Wechselwirkung zwischen Ferrocen / Ferrocenium (polyvinylferrocenbasierte Materialien) verhindern und nur ein LMCT Übergang (Ligand zu Metall Charge-Transfer) beobachtet werden kann
Castellucci, Matt. „Resistive heating for self-healing materials based on ionomeric polymers“. Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/33920.
Master of Science
Lu, Junyong. „Micro fingerprint sensor based on piezoresistive nanocomposite polymers /“. View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?MECH%202008%20LU.
Wei, Chunding. „HIGH-PERFORMANCE ASYMMETRIC SUPERCAPACITORS MAINLY BASED ON METAL CHALCOGENIDE COMPOUNDS ELECTRODE MATERIALS“. University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1495205811288013.
Garge, Swapnil. „Development of an inference based control scheme for reactive extrusion processes“. Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 236 p, 2007. http://proquest.umi.com/pqdweb?did=1362532031&sid=11&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Zhang, Xuan. „Dithienopyrrole-based conjugated materials for organic electronics“. Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/37207.
Mehra, Nitin. „Thermal Conduction in Polymer Based Materials by Engineering Intermolecular Interactions“. University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1578202939238852.
Rose, Ian James. „Triptycene-based polymers of intrinsic microporosity for membrane applications“. Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25440.
Yuan, Bingxin. „Acenaphthylene Based CP-PAH Materials for Organic Semiconductors“. OpenSIUC, 2016. https://opensiuc.lib.siu.edu/dissertations/1233.
Bhardwaj, Rahul. „Modification of polylactide bioplastic using hyperbranched polymer based nanostructures“. Diss., Connect to online resource - MSU authorized users, 2008.
Lee, Hai Xiang Dennis. „Self-sealing of cracks in cement-based materials using superabsorbent polymers“. Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534960.
Gcilitshana, Oko Unathi. „Supercapacitor electrode materials based on nanostructured conducting polymers and metal oxides“. Thesis, University of the Western Cape, 2013. http://hdl.handle.net/11394/3532.
Kashfipour, Marjan Alsadat. „Thermal Conductivity Enhancement Of Polymer Based Materials“. University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron156415885613422.
SASSI, MAURO. „Heterocycle-based redox active, electrochromic organic materials“. Doctoral thesis, Università degli Studi di Milano-Bicocca, 2011. http://hdl.handle.net/10281/25393.
Abou, Diwan Charbel. „NOS-based Biopolymers; Towards Novel Thromboresistant No-Release Materials“. Cleveland, Ohio : Cleveland State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1246374684.
Abstract. Title from PDF t.p. (viewed on July 22, 2009). Includes bibliographical references (p. 159-160). Available online via the OhioLINK ETD Center and also available in print.
Challoner, Nicholas Ian. „Novel oligomeric and polymeric materials based upon the dibenzotetraaza[14]annulenes“. Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19439/.
Liang, Wenfeng. „Metal Organic Composites Derived Tin Dioxide/C Nanoparticles For Sodium-Ion Battery“. University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460304081.
Shun, Li. „Studies on 4D printing Thermo-responsive PNIPAM-based materials“. University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron161969592363207.
PIRANI, FEDERICA. „Bio-oriented Micro- and Nano- Structures Based on Stimuli-responsive Polymers“. Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2706874.
Carroli, Marco. „Novel materials for direct X-ray detectors based on semiconducting organic polymers“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9345/.
Jiang, Hongwei. „Functionalized siloxane based polymers and network materials for second-order nonlinear optics“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0020/NQ50071.pdf.
Jiang, Hongwei 1962. „Functionalized siloxane based polymers and network materials for second-order nonlinear optics“. Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35842.
Rabindranath, Aravinda Raman. „New DPP- and fluorene based conjugated polymers as sensor and emitter materials“. Aachen Shaker, 2008. http://d-nb.info/994882491/04.
Meng, Nan. „Processing, structure and ferroelectric properties of PVDF-based ferroelectric polymers“. Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/25910.
Wilken, Celeste. „Poly(N-Vinylpyrrolidone) based biomimetic hydrogels“. Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20004.
ENGLISH ABSTRACT: In the modern, fast moving society of today, there is a strong focus in research placed on the elimination of lengthy invasive medical procedures. Target specific, and chemo selective treatments are of great interest. Various advantages of this include patient comfort and over and above all cost reduction of invasive procedures. This project focused on the development of an injectable gel system with the use of biocompatible polymers. A system is regarded as injectable if the functional polymers are in solution before administration, but gels when added together. In order to design this system, one has to make use of polymers with complimentary functional groups. Telechelic amino-functionalized PVP with narrow molecular weight distribution was synthesized via RAFT-mediated polymerization. The polymer was thoroughly characterized and cross-linked with Poly(styrene-alt-maleic anhydride) to form a three dimensional polymeric network capable of absorbing and retaining large amounts of water and or biological fluid. Unfortunately the cross-linking needed to be performed in non-aqueous solution due to hydrolysis of maleic anhydride as a competing reaction in water. The gel was used in two model studies. The first model study focused on the attachment of a synthetic polypeptide onto the gel. The second model study evaluated the cytotoxicity effects of these gels when placed in direct contact with rodent cardiac myoblast and myocyte cells. These studies rendered promising results for future biological applications.
AFRIKAANSE OPSOMMING: In die moderne, vinnig bewegende samelewing van vandag, word daar in navorsing, 'n sterk fokus geplaas op die uitskakeling van lang indringende mediese prosedures. Doel spesifieke, en chemo selektiewe behandelings is van groot belang. Verskeie voordele van hierdie is die toename in gemak van die pasiënt en die verlaging van kostes verbonde aan hierdie indringende prosedures. Hierdie projek het gefokus op die ontwikkeling van 'n inspuitbare gel stelsel deur gebruik te maak van biologiese aanvaarbare polimere. ‘n Stelsel word beskou as inspuitbaar, indien die funksionele polimere in oplossing is voor toediening, maar wel kan gel wanneer bymekaar gevoeg word. Om hierdie tipe stelsel te kan ontwerp moet daar gebruik gemaak word van polimere met beskikbare funksionele groepe. Telecheliese amino-funksionele Poly(N-vinielpirollideen) met 'n smal molekulêre gewig verspreiding is gesintetiseer deur middel van RAFT-bemiddelde polimerisasie. Die polimeer is deeglik gekarakteriseer en daarna gekruis-koppel met P(STY-alt-MAnh) om 'n driedimensionele polimeriese netwerk te vorm. Hierdie netwerk is dan ook in staat om groot hoeveelhede water en/of biologiese vloeistof te absorbeer en te behou. Ongelukkig was hierdie reaksie uitgevoer in ʼn nie-waterige oplossing as gevolg van die hidrolise van Maleïne anhydride as 'n mededingende reaksie in water. Die gel is in twee model studies gebruik. Die eerste model-studie het gefokus op die beslaglegging van 'n sintetiese polipeptied op die gel. Die tweede model studie het die sitotoksiese uitwerking van hierdie gels in direkte kontak met knaagdier hart myoblast en lymfocyten selle geëvalueer. Hierdie studies het dan ook belowende resultate vir toekomstige biologiese toepassings gelewer.
Liao, Jessica Huien 1979. „Particle sensors based on amplified quenching of conjugated polymers for biosensing applications“. Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39482.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Vita.
Includes bibliographical references.
Conjugated polymers (CP)s display unique material properties that allow for implementation as sensors. For sensors to operate in complex biological environments, it is important to address the issues of sensitivity and specificity. To develop these attributes in a biosensor design, CPbased core-shell particles have been investigated as potential material platforms to detect protease activity. CP-based particles have greater sensitivity versus CPs in solution due to interchain and intrachain interactions afforded in the solid state. The CP core of the particle can be made using layer-by-layer assembly, a versatile technique that forms uniform polymeric films through non-covalent interactions. To measure the response of CP core particles in aqueous environments, a quantitative ratiometric approach was developed to account for system fluctuations encountered with particle dispersions. This method can help assess the molecular design of polymers and quenchers in a systematic approach. CP core particles, because of their electrostatic charge, suffer from nonspecific interactions with other charged species, and thus encapsulating CP particles with a hydrogel shell should create sensor materials with higher specificity.
(cont.) To illustrate this concept, CP-particle containing hydrogel films were created to permit selective interactions with designed quenchers. The encapsulation of the individual CPcore particles was accomplished through atom transfer radical polymerization (ATRP) of functional monomers from the surface, and the choice of reactive group on the monomer allows for bioconjugation on the particle shell. Future core-shell materials can also be developed with ATRP, and give prospects to new schemes for CP-based biosensing.
by Jessica Huien Liao.
Ph.D.
Ateh, Davidson Day. „Study of epithelial cells on polypyrrole based conducting polymers using electrochemical impedance spectroscopy“. Thesis, Queen Mary, University of London, 2005. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1749.
Gunbas, Gorkem E. „Novel Donor-acceptor Type Polymers Towards Excellent Neutral State Green Polymeric Materials For Realization Of Rgb Based Electrochromic Device Applications“. Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12609002/index.pdf.
Murima, Douglas. „Novel barrier coatings based on nanoclay-polymer composites“. Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96994.
ENGLISH ABSTRACT: The investigation of the barrier properties of highly filled polymer-clay hybrid latex films is described. Montmorillonite (MMT) clay contents ranging from 10–30 wt.% were effectively incorporated into polystyrene-butyl acrylate (PSBA) random copolymers, via miniemulsion polymerization. The optical properties of the films were evaluated using UV-Vis spectroscopy. Compared to the neat films, the PSBA nanocomposites retained remarkable visual properties. The light transmittance for PSBA films with styrene/n-butyl acrylate (S/BA) comonomer contents of 40:60 and 50:50 (mol.%) only decreased from 70% in the neat films to 50% in the nanocomposite films containing 30 wt.% clay. The best optical properties were observed in the films with S/BA comonomer contents of 30:70 (mol.%), the light transmittance only decreased from 85% (neat film) to 60% in the nanocomposite films containing 30 wt.% clay. The improved optical properties for the PSBA-30:70 films (compared to the PSBA-40:60 and PSBA-50:50 counterparts) were attributed to an increase in the low UV-absorbing butyl acrylate component of the copolymer, which at the same time has a low Tg that probably facilitated dispersion of the rigid MMT platelets in the matrix. In this study, the overall water vapour transport behaviour was governed by the MMT clay presence and less affected by the copolymer composition variation. The lower diffusion coefficients in the polymer clay nanocomposites (PCNs) were a result of the impermeable clay platelets which forced the water vapour molecules to follow longer and more tortuous paths to diffuse through the nanocomposite films. The irregular shape in the PSBA-40:60 and PSBA-30:70 neat latex particles was lost in the hybrid particles and well defined, dumb-bell shaped particles were observed. This was because of the faceting effect of the rigid MMT clay platelets. The MMT clay platelets were predominantly adhered to the surface of the PSBA latex particles because MMT clay particles have a larger size than the effective size of the copolymer particles. The stable overall transport coefficients in the PSBA-30:70-MMT films were attributed to the morphological organization of clay platelets in the matrix. The storage modulus of the materials decreased with an increase in clay content. This was attributed to the dual role played by the organoclay, firstly as nanofiller and reinforcing agent leading to the increase in storage modulus, and secondly as a plasticizer leading to a decrease of storage modulus.
AFRIKAANSE OPSOMMING: Die versperringseienskappe van hoogsgevulde polimeer-klei saamgestelde latekslae is beskryf. „n 10–30 wt % Montmorilloniet (MMT) klei inhoud is inkorporeer in polistireenbutielakrilaat (PSBA) onreëlmatige kopolimere, via miniemulsie polimerisasie. Die optiese eienskappe van die lae is bepaal m.b.v. UV-Vis spektroskopie. In vergelyking met die lae sonder klei (sogenaamde „neat films‟), het die PSBA nanosamestellings interressante visuele eienskappe getoon. Die ligtransmissie van die PSBA lae met „n stireeen/n-butielakrilaat (S/BA) komonomeerinhoud van 40:60 en 50:50 (mol %) het slegs afgeneem vanaf 70% in die „neat films‟ tot 50% in the nanosaamgestelde lae wat 30% klei bevat het. Die beste optiese eienskappe is waargeneem vir die lae wat „n 30:70 (mol %) S/BA komonomeerinhoud bevat het; die transmissie het slegs afgeneem vanaf 85% in die „neat films‟ to 60% in the nanosaamgestelde lae wat 30% klei bevat het. Die verbeterde optiese eienskappe van die PSBA-30:70 films (in vergelyking met die -40:60 and -50:50 films) is toegeskryf aan „n toename in die lae UV-absorberende butielakrilaat komponent van die kopolimeer. Terselfdetyd het laasgenoemde „n lae Tg-waarde, wat dispersie van die onbuigbare MMT kleiplaatjies in die matriks gefasiliteer het. In hierdie studie is die algehele waterdampvervoer deur die teenwoordigheid van die MMT klei beheer; dit is minder geaffekteer deur variasie in die samestelling van die kopolimeer. Die lae diffusiekoëffisiënte in die polimeer-klei nanosamestellings is as gevolg van die ondeurdringbare kleiplaatjies, wat die waterdampmolekules dwing om langs langer en meer gekronkelde paaie te diffundeer deur die nanosaamgestelde lae. Die onreëlmatige vorm wat gesien is in die PSBA-40:60 and PSBA-30:70 latekspartikels (sonder klei) het geleidelik verdwyn in die saamgestelde partikels, en goed-gedefineerde partikels met die vorm van handgewigte is waargeneem (in TEM beelde). Die rede hiervoor is die sogenaamde „faceting‟ effek, wat deur die onbuigbare MMT kleiplaatjies veroorsaak is. Die MMT kleiplaatjies sit hoofsaaklik aan die oppervlaktes van die PSBA latekspartikels. Die rede hiervoor is dat die MMT kleipartikels groter is as die effektiewe grootte van die kopolimeerpartikels. Die stabiele vervoerkoëffisiënte in die PSBA-30:70-MMT films is aan die unieke morfologiese eienskappe toegeskryf. Die bergingsmodulus van die materiale het monotonies afgeneem met „n toename in klei-inhoud. Dit is toegeskryf aan die tweedelige rol wat die organoklei speel – eerstens as 'n nanovuller en versterkingsmiddel, wat „n toename in bergingsmodulus tot gevolg het, en tweedens as „n plastiseerder, wat „n afname in bergingsmodulus tot gevolg het.
Silva, Kodikara Manjula Dilkushi. „Environmentally friendly packaging materials from renewable resources as alternatives for oil-based polymers“. Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6453.
Guigo, Nathanaël. „Biomass based materials : polymers, composites and nano-hybrids from furfuryl alcohol and lignin“. Nice, 2008. http://www.theses.fr/2008NICE4062.
This doctoral project has been conducted within the Ecobinders project which aims to develop new binders based on renewable resources such as furfuryl alcohol and/or lignin. Model-free kinetic and chemorheological analysis of furfuryl alcohol polymerisation have highlighted the different rate determing steps and the phase transitions (gelation, vitrification). The VOC’s released during polymerization have been identified. The influence of lignin incorporation on FA polymerization has been studied and oxidized or plasticized lignins have shown improved reactivity. Lab-scale polyfurfuryl alcohol or polyfurfuryl alcohol / lignin resins and thermoset have been elaborated on the basis of kinetic predictions. Evaluation of thermal instability, relaxation behaviour and morphological aspects of these lab-scale thermosets has highlighted a good compatibility between lignin and furanic network. Moreover, a polyfurfuryl alcohol / silica hybrid synthesized via sol-gel process has shown improved thermal performances as the consequence of nanoscales dispersion of silica particles. The quality control on new Ecobinders prototypes has been established. Dynamic aspects of lignin glass transition have been analyzed with multifrequency DSC together with other techniques. The influence of water sorption, thermal annealing, plasticization and fractionation has been considered. New layered silicate nanocomposite has been elaborated with lignin / natural fibres and improved thermal resistance has been shown
DANESH, CAMERON DEAN. „SURFACTANT FORMULATIONS FOR WATER-BASED PROCESSING OF A POLYTHIOPHENE DERIVATIVE“. DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1058.
Giammanco, Giuseppe E. „Photochemistry of Fe(III)-carboxylates in polysaccharide-based materials with tunable mechanical properties“. Bowling Green State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1478602282499732.
Fan, Weizheng. „Development of multifunctional polymeric single-chain nanoparticles based on stimuli-responsive polymers“. Thèse, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10991.
Abstract : With interests on nanoscience and nanotechnology for many applications, there is a demand for development of fabrication technology of ultra-small nano-size objects that allow for precise size control and tailored functionality. Recently, a new technology called ‘single-chain technology’, which manipulates a single polymer chain, becomes a rapidly-growing research topic. This technology provides a facile method to prepare polymer single-chain nanoparticles (SCNPs) with a typical size of 1.5-20 nm. Due to the ultra-small size-enabled unique properties, SCNPs have wide range of applications, including sensor, catalytic system, low viscosity coating, nanoreactor and biomedical applications. Through the contributions by many scientists in the past decade, the synthetic methodologies to fabricate SCNPs have been reported using various chemistries and been getting mature. However, there are still several unsolved problems in the field of SCNPs including functions and application. Stimuli-responsive polymers, as a class of smart materials whose properties can be changed by responding to external stimuli, have been widely used in energy and biomedical applications. Since their chemical and physical properties can be changed easily and efficiently via environmental control, stimuli-responsive polymers provide a potential pathway to preparing functional SCNPs. In this thesis, we are focusing on developing functional SCNPs, especially systems with multi-functions, and expanding their applications. To achieve this target, various stimuli-responsive polymers were prepared as polymer precursors and their stimuli-responsive properties were introduced into the SCNP systems by rational design of their chemical structures. The core of this thesis is comprised of three projects which deal with three classes of SCNPs from stimuli-responsive polymers. These stimuli-responsive SCNPs perform multi-functions and undergo certain change either in structure or morphology and properties. In addition, according to their variety of functions, each class of multi-functional SCNPs has diverse potential applications. In the first study presented in the thesis (Chapter 1), we prepared a class of sub-10 nm photodegradable and size-tunable SCNPs based on photo-responsive main-chain coumarin-based polyesters Poly{[7-(hydroxypropoxy)-4-(hydroxymethyl)coumarin adipate]-co- (polypropylene glycol adipate)} (CAPPG) through copolymerization of coumarin diol, adipic acid and polypropylene glycol (PPG). By incorporating coumarin moieties into the chain backbone of a polyester, dual photo-responsive reaction, i.e. photo-dimerization (>320 nm) and photo-induced chain scission (254 nm), occur under two different wavelengths of UV irradiation, enabling the preparation of sub-10 nm SCNPs and their photo-degradation property. The photo-degradability of SCNPs is evidenced under 254 nm UV irradiation for 3 h, which molecular weight of SCNPs decreasing from 13220 g/mol to 1385 g/mol. Moreover, the size of SCNPs can be tunable from 5.3 nm to 3 nm (hydrodynamic diameter) by varying the dimerization degree of coumarin moieties, that is simply controlled by the UV irradiation time. These results demonstrate a facile method to control the size of SCNPs without the need for synthesizing different polymer precursors. Finally, due to the biocompatible and biodegradable nature of polyester as polymer precursor, the SCNPs with photo-degradability and size-tunability have the potential to be exploited for biomedical applications. In the second study realized in this thesis (Chapter 2), we prepared a new type of multi-functional SCNPs from a side-chain liquid crystalline polymer (SCLCP), namely poly{6-[4-(4-methoxyphenylazo) phenoxy]hexylmethacrylate-co-4-methyl-[7-(methacr-yloyl) oxy-ethyl-oxy]coumarin} (PAzoMACMA). The polymer’s side groups comprise photo-isomerizable azobenzene in majority and photo-dimerizable coumarin in minority, with the former as mesogens and the latter for intra-chain photo-crosslinking. Despite the sub-15 nm size, confinement and crosslinking, the liquid crystalline (LC) phases of bulk PAzoMACMA persist in SCLCPs. Such LC-SCNPs exhibit a number of interesting and peculiar properties. While their dispersion in THF is non-fluorescent, when dispersed in chloroform, the nanoparticles appear to agglomerate to certain degree and display significant fluorescence that is different for SCNPs rich in the trans or cis isomer of azobenzene. The azobenzene LC-SCNPs also undergo photo-induced deformation, similar to azobenzene micro- or colloidal particles. However, the elongational deformation of the nanoparticles is dependent upon the linearly polarized excitation wavelength. While under polarized 365 nm UV irradiation the SCNP stretching direction is perpendicular to the light polarization, under polarized 400-500 nm visible light irradiation, the stretching takes place along the light polarization direction. Finally, an all-polymer nanocomposite was prepared by dispersing the LC-SCNPs in poly(methyl methacrylate) (PMMA), and mechanically stretching-induced orientation of azobenzene mesogens developed along the strain direction. The interesting properties of LC-SCNPs unveiled in this study suggest new possibilities for applications including bio-imaging and LC materials. As the third study in this thesis (Chapter 3), we studied a class of CO2-responsive SCNPs and their self-assembled micellar aggregates. On one hand, SCNPs are prepared from a random copolymer of poly{(N,N-dimethylaminoethyl methacrylate)-co-4-methyl-[7-(methacryloyl)oxyethyl-oxy]coumarin} (P(DMAEMA-co-CMA)). When dispersed in aqueous solution, individual nanoparticles can undergo reversible swelling/shrinking under alternating CO2/N2 stimulation as a result of the reversible protonation/deprotonation of tertiary amine groups. On the other hand, tadpole-like single-chain ‘Janus’ nanoparticles (SCJNPs) are prepared using an amphiphilic diblock copolymer of PS-b-P(DMAEMA-co-CMA) (PS is hydrophobic polystyrene). This type of SCJNPs can self-assemble into core-shell micellar aggregates in aqueous solution. Under CO2/N2 stimulation, the collective swelling/shrinking of SCJNPs within the micelle results in large, reversible volume change. In addition, both P(DMAEMA-co-CMA) SCNPs and PS-b-P(DMAEMA-co-CMA) SCJNP micelles are explored as gas-tunable nanoreactors for gold nanoparticles (AuNPs). The rate of AuNP formation increases under CO2 stimulation and decreases upon N2 bubbling, which makes it possible to tune the reaction rate up and down (on/off switching) by using the two gases. Moreover, using the micelles of SCJNPs, whose volume can be controlled over a wide range by adjusting the CO2 stimulation strength, variable-size AuNPs and their aggregates are obtained with continuous redshift of the surface plasmon resonance (SPR) into the long wavelength visible light region.