Thuringian Institute for Textile and Plastics Research

Rudolstadt, Germany

Thuringian Institute for Textile and Plastics Research

Rudolstadt, Germany
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Vu-Manh H.,University of Innsbruck | Vu-Manh H.,Hanoi University of Science and Technology | Wendler F.,Thuringian Institute for Textile and Plastics Research | Ozturk H.B.,University of Innsbruck | Bechtold T.,University of Innsbruck
Carbohydrate Polymers | Year: 2012

Dynamic rheology, UV/VIS spectrometry with temperature programming cuvette and reaction calorimetry were conducted on cellulose pulp/FeTNa (NaOH solution containing ferric tartaric acid complex) solutions to investigate their thermostability and spinnability. Color of cellulose/FeTNa solutions changed above 90 °C due to the decomposition of the complex. Thermal activity of cellulose/FeTNa solution started above 130 °C induced by water vapor evolution and complex decomposition. Regeneration of cellulose/FeTNa solutions in a non-solvent (acetic acid and Na-gluconate mixture) resulted in transition from cellulose I into cellulose II structure as revealed by WAXS measurements. Wet-spinning attempts of cellulose/FeTNa solutions yielded fiber-like shaped bodies with a brittle structure. © 2011 Elsevier Ltd. All Rights Reserved.


Wendler F.,Thuringian Institute for Textile and Plastics Research | Persin Z.,University of Maribor | Stana-Kleinschek K.,University of Maribor | Reischl M.,University of Graz | And 4 more authors.
Cellulose | Year: 2011

The aim of this study was to find newly structured biopolymer blends bearing those adjustable features able to produce innovative materials. Apart from cellulose derivatives (cellulose carbamate and carboxymethyl cellulose), mannans (guar gum, locust bean gum, and tragacanth gum), xylan, starch (cationized), ι-carrageenan, and xanthan were chosen as blend polysaccharides for cellulose as matrix. In order to study their integration into the cellulose skeleton, fibers were shaped from three different solvents: NaOH by a special wet-spinning process, as well as N-methylmorpholine-N-oxide (NMMO) and 1-ethyl-3-methylimidazolium acetate (EMIMac) via Lyocell technology. The structure and morphologies of the fibers were analyzed by X-ray wide-angle scattering and atomic force microscopy. Hydrophilic/hydrophobic properties were determined by means of a contact angle, as well as moisture content and water retention values, while the surface properties throughout zeta-potential measurements. Being very different processes, the wet spinning in NaOH solution and the dry-wet spinning are deeply impacted by the types of solvent and polysaccharide. The X-ray results for NMMO fibers revealed the highest orientation compared with EMIMac having the lowest orientation of NaOH fibrous types. AFM images also show the lowest surface roughnesses for NMMO and EMIMac fibers. The moisture content and water retention values support these trends, while the water contact angle results show insignificant differences between the samples from EMIMac and NaOH, even though the values calculated for NMMO fibers were the lowest. © 2011 Springer Science+Business Media B.V.


Lepri F.G.,Federal University of Santa Catarina | Borges D.L.G.,Federal University of Santa Catarina | Araujo R.G.O.,Federal University of Santa Catarina | Araujo R.G.O.,Federal University of Sergipe | And 5 more authors.
Talanta | Year: 2010

Reactivity and concentration of additives, especially activated charcoal, employed for the Lyocell process, enhance the complexity of reactions in cellulose/N-methylmorpholine-N-oxide monohydrate solutions. Analytical control of the starting materials is a basic requirement to know the concentration of heavy metals, which are potential initiators of autocatalytic reactions. Seven activated charcoal and two carbon black samples have been analyzed regarding their content of seven elements, Cr, Cu, Fe, Mn, Mo, Ni and V using direct solid sampling high-resolution continuum source graphite furnace AAS (SS-HR-CS GF AAS) and inductively coupled plasma optical emission spectrometry (ICP OES) after microwave-assisted acidic digestion as a reference method. The limits of detection of the former technique are 1-2 orders of magnitude lower than those of ICP OES and comparable to those of more sophisticated techniques. For iron the working range of HR-CS GF AAS has been expanded by simultaneous measurement at two secondary absorption lines (344,099 nm and 344,399 nm). Partial least-squares regression between measured and calculated temperatures for beginning exothermicity (Ton) has been used to investigate the prediction capability of the investigated techniques. Whereas the ICP OES measurements for seven elements resulted in an error of prediction of 3.67%, the results obtained by SS-HR-CS GF AAS exhibited a correlation coefficient of 0.99 and an error of prediction of only 0.68%. Acceptable correlation has been obtained with the latter technique measuring only three to four elements. © 2010 Elsevier B.V. All rights reserved.


Gericke M.,Åbo Akademi University | Gericke M.,Thuringian Institute for Textile and Plastics Research | Schaller J.,Thuringian Institute for Textile and Plastics Research | Liebert T.,Friedrich - Schiller University of Jena | And 5 more authors.
Carbohydrate Polymers | Year: 2012

The tosylation of cellulose in ionic liquids (ILs) was studied. Due to the beneficial effect of different co-solvents, the reaction could be performed at 25 °C without the need of heating (in order to reduce viscosity) or cooling (in order to prevent side reactions). The effects of reaction parameters, such as time, molar ratio, and type of base, on the degree of substitution (DS) with tosyl- and chloro-deoxy groups as well as on the molecular weight were evaluated. Products with a DS tosyl ≤ 1.14 and DS Cl ≤ 0.16 were obtained and characterized by means of NMR- and FT-IR spectroscopy in order to evaluate their purity and distribution of functional groups within the modified anhydroglucose unit (AGU). Tosylation of cellulose in mixtures of IL and a co-solvent was found to result in predominant substitution at the primary hydroxyl group. Size exclusion chromatography (SEC) revealed only a moderate degradation of the polymer backbone at a reaction time of 4-8 h. Finally, the nucleophilic displacement (S N) of tosyl- and chloro-deoxy groups by azide as well as recycling of the ILs was studied. © 2012 Elsevier Ltd. All rights reserved.


Hesse-Ertelt S.,Thuringian Institute for Textile and Plastics Research | Hesse-Ertelt S.,Friedrich - Schiller University of Jena | Heinze T.,Thuringian Institute for Textile and Plastics Research | Heinze T.,Friedrich - Schiller University of Jena | And 3 more authors.
Macromolecular Symposia | Year: 2010

The interactions of ionic liquids (IL) with solvents usually used in liquid-state nuclear magnetic resonance (NMR) spectroscopy are studied. The 1H-and 13C-NMR chemical shift values of 1-n-butyl-3-methyl (BM)-and 1-ethyl-3-methyl (EM)-substituted imidazolium (IM)-chlorides (Cl) and-acetates (Ac) are determined before and after diluting with deuterated solvents (DMSO-d6, D2O, CD3OD, and CDCl3). The dilution offers structural modifications of the IL due to the solvents capacity to ionization. For further investigation of highly viscous cellulose dopes made of imidazolium-based IL, solid-state NMR spectroscopy enables the reproducibility of liquid-state NMR data of pure IL. The correlation of liquid-and solid-state NMR is shown on EMIM-Ac and cellulose/EMIM-Ac dope (10 wt %). Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Cheng F.,University of Hull | Betts J.W.,University of Hull | Kelly S.M.,University of Hull | Schaller J.,Thuringian Institute for Textile and Plastics Research | Heinze T.,Friedrich - Schiller University of Jena
Green Chemistry | Year: 2013

A simple, environmentally friendly and cost-effective synthetic method has been developed to prepare highly stable aqueous colloidal solutions of small (2-14 nm) silver nanoparticles using aminocellulose (AMC) as a combined reducing and capping reagent. The effects of temperature, reaction time, the concentration of silver nitrate and AMC are systematically investigated and the reaction conditions optimised. The AMC-stabilized silver nanoparticles can be deposited on the surfaces of cotton fibres and microporous cellulose acetate (CA) filters, without affecting the permeability of the filters. The AMC-stabilized aqueous silver colloidal solutions and silver nanoparticle coated CA filters and cotton fibres all show significant antibacterial action against all the bacterial isolates tested, with the antibacterial levels between "Sufficient" and "Good", although some of solutions have been stored at room temperature for 18 months. © 2013 The Royal Society of Chemistry.


PubMed | Åbo Akademi University, Thuringian Institute for Textile and Plastics Research and Friedrich - Schiller University of Jena
Type: Journal Article | Journal: Carbohydrate polymers | Year: 2014

The tosylation of cellulose in ionic liquids (ILs) was studied. Due to the beneficial effect of different co-solvents, the reaction could be performed at 25C without the need of heating (in order to reduce viscosity) or cooling (in order to prevent side reactions). The effects of reaction parameters, such as time, molar ratio, and type of base, on the degree of substitution (DS) with tosyl- and chloro-deoxy groups as well as on the molecular weight were evaluated. Products with a DStosyl1.14 and DSCl0.16 were obtained and characterized by means of NMR- and FT-IR spectroscopy in order to evaluate their purity and distribution of functional groups within the modified anhydroglucose unit (AGU). Tosylation of cellulose in mixtures of IL and a co-solvent was found to result in predominant substitution at the primary hydroxyl group. Size exclusion chromatography (SEC) revealed only a moderate degradation of the polymer backbone at a reaction time of 4-8h. Finally, the nucleophilic displacement (SN) of tosyl- and chloro-deoxy groups by azide as well as recycling of the ILs was studied.


Doebel C.,Thuringian Institute for Textile and Plastics Research | Ament C.,TU Ilmenau
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2014

An adaptive, optimizing device management system for households called ENKOS is developed that is based on learning classifier systems (LCS). Established methods and algorithms are extended, and psychology methods are introduced to solve specific generalization and adoption problems. The two aims of ENKOS are firstly to minimize the electrical energy consumption within the household by interpreting the user's wishes as servable and controlling the devices in that kind, and secondly to maximize the consumer comfort by predicting the wishes of them by learning. This paper shows both the feasibility to meet the aims by using learning classifier systems with extensions as new methods, and the influence of several parameters towards the value of the learning rate of the objective function. © IFAC.


Eisenhawer B.,Institute of Photonic Technology | Sensfuss S.,Thuringian Institute for Textile and Plastics Research | Sivakov V.,Institute of Photonic Technology | Pietsch M.,Institute of Photonic Technology | And 3 more authors.
Nanotechnology | Year: 2011

Silicon nanowires have been introduced into P3HT:[60]PCBM solar cells, resulting in hybrid organic/inorganic solar cells. A cell efficiency of 4.2% has been achieved, which is a relative improvement of 10% compared to a reference cell produced without nanowires. This increase in cell performance is possibly due to an enhancement of the electron transport properties imposed by the silicon nanowires. In this paper, we present a novel approach for introducing the nanowires by mixing them into the polymer blend and subsequently coating the polymer/nanowire blend onto a substrate. This new onset may represent a viable pathway to producing nanowire-enhanced polymer solar cells in a reel to reel process. © 2011 IOP Publishing Ltd.


Wendler F.,Thuringian Institute for Textile and Plastics Research | Todi L.-N.,Thuringian Institute for Textile and Plastics Research | Meister F.,Thuringian Institute for Textile and Plastics Research
Thermochimica Acta | Year: 2012

Ionic liquids (ILs) exhibit a far lower degradation potential compared to the established direct cellulose solvent N-methylmorpholine-N-oxide monohydrate used in the Lyocell process. Safety parameters such as onset temperature, pressure rise and heat release during exothermicity were measured in imidazolium ILs and solutions of cellulose in ILs by means of DSC, dynamic reaction calorimetry and UV/VIS spectroscopy with a special designed cuvette. Onset temperatures were determined using pressure rise measurement at a threshold value. Initial thermal activities in ILs occurred at much lower temperatures compared to DSC measurements and TGA literature data. For 1-ethyl-3- methylimidazolium acetate (EMIMAc) and 1-butyl-3-methylimidazolium acetate (BMIMAc) the onset temperatures 181 and 179°C, respectively, were stated first time. Endothermic decomposition of pure EMIMAc is turned to an exothermic event by addition of cellulose accompanied by increased slope of pressure. © 2011 Elsevier B.V. All rights reserved.

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