TY - CONF A1 - Unger, Brita T1 - Sol-gel-Chemie und Werkstoffverbunde T2 - Abteilungsseminar, Abteilung VI, BAM T2 - Abteilungsseminar, Abteilung VI, BAM CY - Berlin, Germany DA - 2003-09-04 PY - 2003 AN - OPUS4-5413 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unger, Brita A1 - Rurack, Knut A1 - Müller, Ralf A1 - Jancke, Harald A1 - Resch-Genger, Ute T1 - Microscopic vs. macroscopic structural evolution of SiO2 sols and gels employing a tailor-made fluorescent reporter dye JF - Journal of materials chemistry N2 - The short- and long-term structural evolution and aging of sol–gel materials prepared under mild conditions are studied by fluorometry, dynamic light scattering (DLS), 29Si NMR and gravimetry. In combination with the first, a newly developed donor–acceptor-substituted fluorescent probe with two acidophilic sites of different strength and topology is introduced. Its performance in detecting changes in parameters such as polarity, proticity, and pore volume on the microscopic scale is compared to two other dyes and to the macroscopic changes revealed by DLS, NMR and gravimetry. At early stages of the sol–gel process, fluorometry, DLS and NMR reveal similar changes which are typical of the structural evolution of SiO2 sols having different synthesis parameters. During later times of sol aging, DLS and NMR reflect the growth of the network and indicate that all sols approach similar structural equilibria. Fluorometry supports these findings by signalling a gradual decrease in mobile species with high proton activity. The formation of the spanning cluster upon gelation is strongly evident only from DLS results while the local environment of the fluorophore remains largely unchanged. However, the fluorescent dye is able to report microscopic changes even during long-term aging. Drying of the gels with a pronounced contraction of solvated pores is readily observable by fluorometry and gravimetry. During the late reaction stages, the fluorescence properties of the tailor-made dye are still sensitive toward the environment. PY - 2005 DO - https://doi.org/10.1039/b501622c SN - 0959-9428 SN - 1364-5501 VL - 15 IS - 30 SP - 3069 EP - 3083 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-10378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Brita A1 - Jancke, Harald A1 - Müller, Bernd R. A1 - Unger, Wolfgang A1 - Reinsch, Stefan A1 - Nofz, Marianne T1 - Strukturbildungsprozesse in Gelglässern T2 - XXV. Tagung des Arbeitskreises "Nichtkristalline und partiellkristalline Strukturen" der Deutschen Gesellschaft für Kristallographie T2 - XXV. Tagung des Arbeitskreises "Nichtkristalline und partiellkristalline Strukturen" der Deutschen Gesellschaft für Kristallographie CY - Wolfersdorf, Germany DA - 2004-09-27 PY - 2004 AN - OPUS4-6241 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Böcker, Wolfgang D. G. A1 - Bücker, Michael A1 - Reinsch, Stefan A1 - Unger, Brita T1 - Abschlussbericht zum Vorhaben Verbundwerkstoff - Mineralisiertes Holz - FKZ: 033 9829 - Förderschwerpunkt "Integrierter Umweltschutz im Bereich der Holzwirtschaft" des Bundesministeriums für Bildung, Wissenschaft, Forschung und Technologie, BMBF - Projektlaufzeit: 1.10.2000-30.9.2003 KW - Mineralisiertes Holz KW - Sol-Gel KW - Holz KW - Vakuumtränkung KW - Holzschutz KW - Biozide PY - 2004 SP - 1 EP - 94 CY - Berlin AN - OPUS4-12055 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Brita A1 - Rurack, Knut A1 - Müller, Ralf A1 - Jancke, Harald T1 - Untersuchungen zur Alterung von Kieselsolen und -gelen T2 - XXIV. (11.) Arbeitstagung führte der Arbeitskreis Nichtkristalline und Partiellkristalline Strukturen T2 - XXIV. (11.) Arbeitstagung führte der Arbeitskreis Nichtkristalline und Partiellkristalline Strukturen CY - Wolfersdorf, Germany DA - 2003-09-08 PY - 2003 AN - OPUS4-5352 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bücker, Michael A1 - Böcker, Wolfgang D. G. A1 - Reinsch, Stefan A1 - Unger, Brita T1 - Holzmodifikation durch Tränkung mit Nanopartikeln T2 - Tagungsband "Rosenheimer Fenstertage 2004" T2 - Tagung "Rosenheimer Fenstertage 2004" CY - Rosenheim, Deutschland DA - 2004-01-01 KW - Holzmodifikation KW - Sol-Gel KW - Tränkverfahren KW - Holzschutz PY - 2004 SP - 23 EP - 26 PB - Institut für Fenstertechnik CY - Rosenheim AN - OPUS4-4487 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Brita A1 - Jancke, Harald A1 - Müller, Bernd R. A1 - Müller, Ralf A1 - Unger, Wolfgang A1 - Reinsch, Stefan A1 - Nofz, Marianne T1 - Strukturbildungsprozesse in Solen und Gelen T2 - XXV. Tagung des Arbeitskreises "Nichtkristalline und partiellkristalline Strukturen" der Deutschen Gesellschaft für Kristallographie T2 - XXV. Tagung des Arbeitskreises "Nichtkristalline und partiellkristalline Strukturen" der Deutschen Gesellschaft für Kristallographie CY - Wolfersdorf, Germany DA - 2004-09-27 PY - 2004 AN - OPUS4-5619 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Raedel, Martina A1 - Sabel, Martin A1 - Bücker, Michael A1 - Unger, Brita ED - Meeks, N. ED - Cartwright, C. ED - Meek, A. ED - Mongiatti, A. T1 - ESEM-EDX analyses for the characterisation and reproduction of nineteenth-century gold tesserae T2 - Historical technology, materials and conservation - SEM and microanalysis N2 - Environmental scanning electron microscopy with energy dispersive X-ray analysis (ESEM-EDX) is a versatile working tool for the examination of gold tesserae as well as for the selection of suitable materials for their reproduction. In this paper, the ESEM-EDX analyses of original gold tesserae and their damage types are presented. These analytical results form the basis for further calculations of glass properties and experiments. These calculated values enable the determination of the relevant glass properties and allow us to choose the appropriate type of modern glass for further experiments. Subsequent experiments convert this knowledge into practice. By comparing the analytical results from the original glasses and the replicas the accuracy and precision will be shown. KW - Gold mosaics KW - Tesserae KW - ESEM-EDX KW - Glass analyses KW - Damage mechanism PY - 2012 SN - 978-1-904982-65-4 SP - 107 EP - 113 PB - Archetype publications Ltd. AN - OPUS4-27641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unger, Brita A1 - Bücker, Michael A1 - Reinsch, Stefan A1 - Hübert, Thomas T1 - Chemical aspects of wood modification by sol-gel-derived silica JF - Wood science and technology N2 - It has been shown that tetraethoxysilane-derived precursors are suitable solutions for impregnating pine sapwood to improve its dimensional stability. Tailored sol–gel syntheses result in precursors with nano-scaled silica species which are able to penetrate into the cell walls of wood. The physical fixation of those species inside the cell walls was verified by ESEM/EDX investigations. There is evidence that the silica species are chemically bonded to wood components. Nonreacted alkoxy groups can exist in the wood composites after impregnation. The amount of these organic residues depends on the composition of the precursors, especially their condensation degree and reactivity. Treatments for finishing the composites after the impregnation step to get clean products and stable properties are discussed in this context. An explanation of the complex relationship between solids content in the impregnation solutions and percentage weight gain and bulking of the composites is given. It can be demonstrated that high WPG values (>20 %) are pre-conditions for an effective protection of the resulting composites but they only guarantee efficient improvements if connected with the incorporation of the inorganic component inside the cell walls. Therefore, the sol–gel syntheses have to be carried out in such a manner that very small (<2 nm) as well as reactive species are sufficiently available. This demands syntheses using sub-stoichiometric water contents (H2O/TEOS <4, better <2). KW - Silica-wood composites KW - Sol-gel derived precursors KW - Curing KW - Fixation of silica KW - Dimensional stability PY - 2013 DO - https://doi.org/10.1007/s00226-012-0486-7 SN - 0043-7719 SN - 1432-5225 VL - 47 IS - 1 SP - 83 EP - 104 PB - Springer CY - Berlin AN - OPUS4-26258 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bücker, Michael A1 - Böcker, Wolfgang D. G. A1 - Reinsch, Stefan A1 - Unger, Brita T1 - Alternativer Holzschutz JF - Bauelemente Bau KW - Holzschutz KW - Kieselsol KW - Biozide KW - Sol-Gel-Prozess PY - 2004 SN - 1435-1854 IS - 11 SP - 77 EP - 80 PB - Verl. f. Fachpublizistik CY - Stuttgart AN - OPUS4-6333 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Brita A1 - Jancke, Harald A1 - Müller, Renate A1 - Peplinski, Burkhard A1 - Hähnert, Manfred ED - Rüssel, C. T1 - Sol-gel derived precursors for cordierite glass-ceramics T2 - Proceedings of the 5th International Otto Schott Colloquium T2 - 5th International Otto Schott Colloquium ; 5. Internationales Otto-Schott-Kolloquium CY - Jena, Germany DA - 1994-07-10 PY - 1994 SN - 0946-7475 N1 - Serientitel: Glass science and technology – Series title: Glass science and technology IS - 67 SP - 448 EP - 451 PB - Verl. Dt. Glastechn. Ges. CY - Frankfurt/Main AN - OPUS4-12598 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Brita A1 - Müller, R. A1 - Peplinski, Burkhard A1 - Hähnert, Manfred T1 - Sintering and crystallization of amorphous cordierite powders prepared by sol-gel technique T2 - 11th Conference on Glass and Ceramics T2 - 11th Conference on Glass and Ceramics CY - Varna, Bulgaria DA - 1993-10-21 PY - 1993 AN - OPUS4-12616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Brita A1 - Jancke, Harald A1 - Müller, R. A1 - Peplinski, Burkhard A1 - Hähnert, Manfred T1 - Sol-Gel derived precursors for cordierite glass-ceramics T2 - 5th International Otto-Schott-Colloquium T2 - 5th International Otto-Schott-Colloquium CY - Jena, Germany DA - 1994-07-11 PY - 1994 AN - OPUS4-12620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bücker, Michael A1 - Unger, Brita A1 - Böcker, Wolfgang D. G. T1 - Holzmodifikation durch Tränkung mit Nanopartikeln T2 - Ausstellung: "Versteinertes Arboretum - Versteinertes Holz", Naturkundemuseum T2 - Ausstellung: "Versteinertes Arboretum - Versteinertes Holz", Naturkundemuseum CY - Gera, Germany DA - 2007-04-25 PY - 2007 AN - OPUS4-14841 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Raedel, Martina A1 - Unger, Brita A1 - Feldmann, Ines A1 - Bücker, Michael ED - Hauptmann, Andreas ED - Heike Stege, T1 - Untersuchung historischer Goldmosaike Herstellungstechnologie und charakteristische Schadensbilder JF - Metalla KW - Historische Goldmosaike KW - Herstellungstechnologie KW - Schadensbilder KW - Glasanalyse PY - 2009 SN - 0947-6229 SP - 127 EP - 130 PB - Deutsches Bergbau-Museum CY - Bochum AN - OPUS4-19789 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Brita A1 - Shabir Mahr, Muhammad A1 - Sabel, Martin A1 - Pfeifer, Dietmar A1 - Hübert, Thomas T1 - Imprägnierung von Holz mit SiO2- und/oder SiO2-Solen: Fixierung der anorganischen Komponente im Holz T2 - XXXI. Tagung des Arbeitskreises "Nichtkristalline und partiellkristalline Strukturen" der DGK T2 - XXXI. Tagung des Arbeitskreises "Nichtkristalline und partiellkristalline Strukturen" der DGK CY - Wolfersdorf (Berga), Germany DA - 2010-10-11 PY - 2010 AN - OPUS4-22327 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Raedel, Martina A1 - Bücker, Michael A1 - Unger, Brita T1 - Historische und moderne Goldmosaike im Vergleich JF - Metalla / Sonderheft KW - Historische und moderne Goldmosaike KW - Aufbau KW - Besonderheiten KW - Herstellungstechnik KW - Glaszusammensetzung KW - EDX-Analyse KW - Viskositäts-Temperatur-Verhalten KW - Ausdehnungskoeffizient PY - 2010 SN - 0947-6229 IS - 3 SP - 184 EP - 185 PB - Dt. Bergbau-Museum CY - Bochum AN - OPUS4-22707 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hübert, Thomas A1 - Unger, Brita A1 - Bücker, Michael T1 - Sol-gel derived TiO2 wood composites JF - Journal of sol gel science and technology N2 - The sol–gel process was applied to enhance properties of pine sapwood. For this purpose wood prisms were soaked in nanoscaled precursor solutions prepared from titanium(IV) n-butoxide and titanium(IV) iso-propoxide, respectively, using vacuum impregnation technique. The wet composites were cured by special program with final heat treatment at 103 °C. Weight percent gains (WPG) of the wood specimen in the range of 19-25% were obtained due to these procedures. SEM investigations show that precursor solutions penetrate into the whole wood body and the titania formed after heat treatment in the composites is deposited in the pores (lumen) and partly in the cell walls of the wooden matrix. The moisture sorption was investigated in long term tests for a period of some months by storage at 20-23 °C in humid air (relative humidity of 99%) and ambient atmosphere (relative humidity 40-60%), respectively. For untreated reference samples the moisture sorption results in increasing of mass and volume according to saturation values of 24 and 13%, respectively, after about 15 days. The incorporation of titania reduces the saturation values of the moisture sorption by up to 12% in mass and by up to 5% in volume at a relative humidity of 99%. Thus, an enhancement of the dimensional stability of about 60% is obtained at best. The results demonstrate that modification of wood with sol-gel derived precursors can enhance its dimensional stability, which prevents the formation of cracks. Because of that reduced moisture sorption biological attacks should be delimited. Additionally, thermal analyses show a retarded combustion of the wood matrix due to titania infiltration. KW - Titania KW - Sol-gel KW - Nanocomposites KW - Wood protection KW - Water sorption PY - 2010 DO - https://doi.org/10.1007/s10971-009-2107-y SN - 0928-0707 SN - 1573-4846 VL - 53 IS - 2 SP - 384 EP - 389 PB - Kluwer Academic Publ. CY - Dordrecht AN - OPUS4-20892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Raedel, Martina A1 - Unger, Brita A1 - Bücker, Michael A1 - Sabel, Martin A1 - Feldmann, Ines T1 - Gold mosaics - material composites and glass-chemical characteristics T2 - GLASSAC 11 - 3rd GLASSAC Conference 'Glass science in art and conservation' N2 - In this study gold mosaics front the past 130 years are reviewed and analysed. Characteristic glass properties and technological specifics are observed and provide important Information on the production process. The insights gained are used for replicas with improved glass properties. T2 - GLASSAC 11 - 3rd GLASSAC Conference 'Glass science in art and conservation' CY - Wertheim, Bronnbach Monastery, Germany DA - 01.05.2011 KW - Erfassung von Goldmosaiken der letzten 130 Jahre mit Aufbau einer Datenbank KW - Herstellungstechnik und Besonderheiten KW - Schichtaufbau mit Glaszusammensetzung und EDX-analysen KW - Glas-chemische Charakteristika verschiedener Goldmosaiktypen KW - Reproduktion PY - 2011 SN - 978-3-8396-0255-3 SP - 51 EP - 54 PB - Fraunhofer Verlag AN - OPUS4-23842 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bücker, Michael A1 - Jäger, Christian A1 - Pfeifer, Dietmar A1 - Unger, Brita T1 - Evidence of Si-O-C bonds in cellulosic materials modified by sol-gel-derived silica JF - Wood science and technology N2 - The present study contributes to the controversial discussion in the literature whether Si–O–C bonds in wood–silica–gel composites exist. 13C NMR is a suitable method to proof such bonds. Because of the low concentration of 13C isotopes in natural wood, 13C cellulose was used as 13C-enriched substitute. A tailored sol for the impregnation of that cellulose was chosen by liquid 29Si NMR pre-investigations of various sols whose reactivity and stability were time-dependently analysed. It is based on a sub-stoichiometric hydrolysis of tetraethoxysilane (TEOS) with 1 mol water per mol TEOS. Thermal analyses were performed to show a comparability of the thermal behaviour of wood–silica–gel and cellulose–silica–gel composites. There are two strong hints of the existence of stable Si–O–C bonds: (1) by thermal analysis, a shift in the fire behaviour of 100 K can be observed with a change in pyrolysis behaviour of the composite and (2) the proof by REDOR NMR that a dipolar coupling between 1329Si and 13C nuclei exists. KW - Silica-cellulosic composites KW - Sol-gel derived silica KW - Si-O-C bonds KW - 13C NMR KW - 29Si NMR PY - 2014 UR - http://link.springer.com/article/10.1007/s00226-014-0657-9/fulltext.html DO - https://doi.org/10.1007/s00226-014-0657-9 SN - 0043-7719 SN - 1432-5225 VL - 48 IS - 5 SP - 1033 EP - 1047 PB - Springer CY - Berlin AN - OPUS4-31223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinsch, Stefan A1 - Böcker, Wolfgang D. G. A1 - Bücker, Michael A1 - Seeger, Stefan A1 - Unger, Brita ED - Specht, K. T1 - Development of wood-inorganic composites with enhanced properties and environmental stability T2 - 4th International Wood and Natural Fibre Composites Symposium T2 - 4th International Wood and Natural Fibre Composites Symposium CY - Kassel, Germany DA - 2002-04-10 PY - 2002 VL - 4 SP - 50-1-50-6 CY - Kassel AN - OPUS4-1365 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -