1. Carbon foams via ring-opening metathesis polymerization of emulsion templates : a facile method to make carbon current collectors for battery applicationsSebastijan Kovačič, Bettina Schafzahl, Nadejda B. Matsko, Katharina Gruber, Martin Schmuck, Stefan Koller, Stefan A. Freunberger, Christian Slugovc, 2022, original scientific article Keywords: emulsion templating, carbonization, ROMP, polyHIPEs, porous cathode
Published in DKUM: 10.04.2024; Views: 213; Downloads: 19
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2. Porozni organogeli: sinteza in absorpcijaStanko Kramer, 2017, undergraduate thesis Abstract: Geli so v kapljevino namočena mreža polimernih molekul, t.i. gelska mreža, katere agregatno stanje lahko uvrstimo med trdno in kapljevinasto, kar pomeni, da so poltrdi sistem. Glede na topilo jih delimo na organogele (absorbirajo nepolarna (organska) topila) in hidrogele (absorbirajo vodo). Organogeli predstavljajo obetajoče absorpcijske materiale za čiščenje oljnih razlitij, saj imajo visoko specifično površino pod pogoji nabrekanja in so sposobni vpiti večje količine apolarnih tekočin.
V diplomskem delu smo pripravili organogele na osnovi norbornena in njegovih derivatov. Z uporabo emulzij z visokim deležem notranje faze smo pripravili visoko porozne t.i. poliHIPE organogele. S polimerizacijo v raztopini smo pripravili neporozne t.i. bulk organogele.
Sintezo smo izvedli z uporabo metatezne polimerizacije z odpiranjem obroča (ang. Ring Opening Metathesis Polymerisation, ROMP). Nastale organogele iz diciklopentadiena (DCPD), 2-norbornena (NOR) in ciklooktadiena (COD) smo ustrezno karakterizirali, nato smo izvedli test absorpcije organskih topil in dveh različnih naftnih derivatov. Preučili smo kako na absorpcijo vplivajo struktura organogela (porozen oz. neporozen) in stopnja zamreženja polimernega ogrodja.
Porozno morfologijo skeleta smo preučili z elektronsko vrstično mikroskopijo (SEM), medtem ko smo test absorpcije izvedli gravimetrično. S SEM analizo smo dokazali, da so dobljeni organogeli imeli poliHIPE strukturo. Z absorpcijo smo dokazali, da je količina absorbiranih topil pri poliHIPE organogelih večja od bulk organogelov in v nekaterih primerih monoliti absorbirajo več kot 9-kratnik svoje suhe mase.
V primeru absorpcije naftnih derivatov so organogeli bili sposobni absorbirati 7-kratnik svoje suhe mase, medtem ko ponovna uporaba organogelov ni bila tako uspešna, saj je bila največja količina absorbiranega naftnega derivata le nekoliko večja kot masa samega monolita.
Keywords: Metatezna polimerizacija z odprtjem obroča (ROMP), poliHIPE, absorpcija, diciklopentadien, norbornen, ciklooktadien
Published in DKUM: 14.09.2017; Views: 1671; Downloads: 179
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3. Nanocomposite foams from iron oxide stabilized dicyclopentadiene high internal phase emulsions : preparation and brominationSebastijan Kovačič, Christian Slugovc, Gregor Ferk, Nadejda B. Matsko, 2014, professional article Abstract: Nanocomposite polyHIPE foams with open-cellular morphology were obtained using nanoparticles ($γFe_2O_3/Fe_3O_4$), surfactant (Pluronic L121) or nanoparticle/surfactant stabilized dicyclopentadiene high internal phase emulsions (DCPD HIPEs). Upon curing, cavity sizes were found to vary drastically between 950 ± 360 µm down to 7 ±3 µm de- pending on the HIPE formulations. As-obtained nanocomposite polyHIPE foams were functionalized using elemental bromine in THF. Upon bromination the nanoparticles are moved from the cavities surfaces into the bulk phase of the polymer scaffold, which affects the inductive-heating capability of the magnetic nanocomposite foams decreasing it by the factor of 2.
Keywords: chemical technology, nanocomposites, bromination, microstructure, pickering HIPEs, $γFe_2O_3/Fe_3O_4$ nanoparticles, Ring Opening Metathesis Polymerization (ROMP), dicyclopentadiene, inductive heating
Published in DKUM: 24.08.2017; Views: 1237; Downloads: 143
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4. Ring opening metathesis polymerisation (ROMP) as a tool for polyhipes with extraordinary mechanical propertiesSebastijan Kovačič, 2013, professional article Abstract: PolyHIPE materials have been prepared by Ring Opening Metathesis Polymerisation (ROMP) of dicyclopentadiene. Two characteristic features for successful stabilization of high internal phase emulsions (HIPEs) were tuned in order to achieve improvements regarding mechanical properties of polyHIPEs.Mechanical properties of the new materials were related to variations of the surfactant concentration and the volume ratio of the internal phase in HIPEs. Values for Youngʼs moduli were about a hundred times higher than in standard polyHIPE materials with the same level of porosity, which represents a major improvement for highly porous cellular polymeric materials. Moreover, fully interconnected macroporous morphology was found forpolyHIPEs, where respective HIPEs were stabilized with only 0.25 v% of surfactant.
Keywords: emulsion templating, ring opening metathesis polymerization, dicyclopentadiene, ROMP, mechanical characteristics, polyHIPEs
Published in DKUM: 21.12.2015; Views: 2518; Downloads: 104
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5. HYBRID PolyHIPE MATERIALSSebastijan Kovačič, 2011, dissertation Abstract: A new class of polyHIPE materials has been prepared using high internal phase emulsions (HIPEs) with monomers in both phases. Resulting materials, namely hybrid polyHIPE materials, are obtained consisting of hydrophobic matrix (consisted of styrene cross-linked with DVB or dicyclopentadiene) filled with hydrophilic polymer gel (polyacrylic acid or polyNIPAM) and exhibit morphology changes according to pH and temperature of the surrounding medium. Our focus with regards to the production of hybrid polyHIPE materials was the responsiveness of such materials used for flow control. This property is beneficial for controlling the flow of the solution through the monolithic polymers. Furthermore, polyHIPE materials have also been prepared by using ring opening metathesis polymerisation of monomers, such as dicyclopentadiene and norbornene. Obtained materials have Young’s moduli in the range of hundred times higher than standard polyHIPE materials with the same level of porosity which represents a very important improvement in the development of highly porous cellular polymeric materials.
Keywords: emulsions, high internal phase emulsions, polymers, polyHIPEs, hybrid, hybrid polyHIPE materials, ROMP, flow-through, styrene, DVB, acrylic acid, NIPAM
Published in DKUM: 04.05.2011; Views: 3490; Downloads: 328
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