Refine
Document Type
- Journal article (27) (remove)
Is part of the Bibliography
- yes (27)
Institute
- Texoversum (27)
Publisher
- dfv Mediengruppe (10)
- Deutscher Fachverlag (4)
- Elsevier (3)
- MDPI (3)
- IBP, Internat. Business Press Publisher (2)
- American Chemical Society (1)
- Royal Society of Chemistry (1)
- SAGE Publications Ltd (1)
- Springer (1)
- Verlag Textilplus AG (1)
Several ionic liquids are excellent solvents for cellulose. Starting from that finishing of PET fabrics with cellulose dissolved in ionic liquids like 1-ethyl 3-methyl imidazolium acetate, diethylphosphate and chloride, or the chloride of butyl-methyl imidazolium has been investigated. Finishing has been carried out from solutions of different concentrations, using microcrystalline cellulose or cotton and by employing different cross-linkers. Viscosity of solutions has been investigated for different ionic liquids,concentrations, cellulose sources, linkers and temperatures. Since ionic liquids exhibit no vapor pressure,simple pad-dry-cure processes are excluded. Before drying the ionic liquid has to be removed by a rinsing step. Accordingly rinsing with fresh ionic liquid followed by water or the direct rinsing with waterhave been tested. The amount of cellulose deposited has been investigated by gravimetry, zinc chlorideiodine test as well as reactive dyeing. Results concerning wettability, water up-take, surface resistance,wear-resistance or washing stability are presented.
Three established test methods employed for evaluating the abrasion or wear resistance of textile materials were compared to gain deeper insight into the specific damaging mechanisms to better understand a possible comparability of the results of the different tests. The knowledge of these mechanisms is necessary for a systematic development of finishing agents improving the wear resistance of textiles. Martindale, Schopper, and Einlehner tests were used to analyze two different fabrics made of natural (cotton) or synthetic (polyethylene terephthalate) fibers, respectively. Samples were investigated by digital microscopy and scanning electron microscopy to visualize the damage. Damage symptoms are compared and discussed with respect to differences in the damaging mechanisms.
The wet chemical deposition of solution processed transparent conducting oxides (TCO) provides an alternative low cost and economical deposition technique to realize large-areas of conducting films. Since the price for the most common TCO Indium Tin Oxide rises enormously, Aluminum Zinc Oxide (AZO) as alternative TCO reaches more and more interest. The optoelectronical properties of nanoparticle coatings strongly depend beneath the porosity of the coating on the shape and size of the used particles. By using bigger or rod-shaped particles it is possible to minimize the amount of grain boundaries resulting in an improvement of the electrical properties, whereas particles bigger than 100 nm should not be used if highly transparent coatings are necessary as these big particles scatter the visible light and lower the transmittance of the coatings. In this work we present a simple method to synthesize AZO particles with different shape and size, but comparable electronical properties. We use a simple, well reproducible polyol method for synthesis and influence the shape and size of the particles by adding different amounts of water to the precursor solution. We can show that the addition of aluminum as dopant strongly hinders the crystal growth but the addition of water counteracts this, so that both, spherical and rod-shaped particles can be obtained.
Polyester fibers are widely employed in a multitude of sectors and applications from the technical textiles to everyday life thanks to their durability, strength, and flexibility. Despite these advantages, polyester lacks in dyeability, adhesion of coating, hydrophilicity, and it is characterized by a low wettability respect to natural fibers. On this regard, beyond the harmful hydrophobic textile finishings of polyester fabrics containing fluorine-compounds, and in order to avoid pre-treatments, such as laser irradiation to improve their surface properties, research is moving towards the development of fluorine-free and safer coatings. In this work, the (3-glycidyloxypropyl)trimethoxysilane (GPTMS) and various long alkyl-chain alkoxysilanes were employed for the fabrication in the presence of a catalyst of a water-based superhydrophobic finishing for polyester fabrics with a simple sol-gel, non-fluorinated, sustainable approach and the dip-pad-dry-cure method. The finished polyester fabrics surface properties were investigated by static and dynamic water repellency tests. Additionally, the resistance to common water-based liquids, abrasion resistance, moisture adsorption, and air permeability measurements were performed. Scanning electron microscopy was employed to examine the micro- and nano-morphology of the functionalized polyester fabrics surfaces. The obtained superhydrophobic finishings displayed high water-based stain resistance as well as good hydrophobicity after different cycles of abrasion.
The textile-finishing industry, is one of the main sources of persistent organic pollutants in water; in this regard, it is necessary to develop and employ new sustainable approaches for fabric finishing and treatment. This research study shows the development of an efficient and eco-friendly procedure to form highly hydrophobic surfaces on cotton fabrics using different modified silica sols. In particular, the formation of highly hydrophobic surfaces on cotton fabrics was studied by using a two-step treatment procedure, i.e., first applying a hybrid silica sol obtained by hydrolysis and subsequent condensation of (3-Glycidyloxypropyl) trimethoxy silane with different alkyl(trialkoxy) silane under acid conditions, and then applying hydrolyzed hexadecyltrimethoxysilane on the treated fabrics to further improve the fabrics’ hydrophobicity. The treated cotton fabrics showed excellent water repellency with a water contact angle above 150◦ under optimum treatment conditions. The cooperative action of rough surface structure due to the silica sol nanoparticles and the low surface energy caused by long-chain alkyl(trialkoxy)silane in the nanocomposite coating, combined with the expected roughness on microscale due to the fabrics and fiber structure, provided the treated cotton fabrics with excellent, almost super, hydrophobicity and water-based stain resistance in an eco-sustainable way.
Im Zuge von REACH wurden gängige hocheffektive halogenierte Flammschutzmittel verboten, da diese unter dem Verdach stehen, kanzerogen, mutagen und teratogen zu sein. Zur Zeit fehlen entsprechende Alternativen. Daher werden am DTNW neue umweltfreundliche und halogenfreie Flammschutzmittel auf der Basis von Phosphor- und Stickstoffverbindungen entwickelt, um einen entsprechenden Flammschutz zu gewährleisten. Neue Möglichkeiten werden im Rahmen dieses Artikels vorgestellt.
Thin, flat textile roofing offers negligible heat insulation. In warm areas, such roofing membranes are therefore equipped with metallized surfaces to reflect solar heat radiation, thus reducing the warming inside a textile building. Heat reflection effects achieved by metallic coatings are always accompanied by shading effects as the metals are non-transparent for visible light (VIS). Transparent conductive oxides (TCOs) are transparent for VIS and are able to reflect heat radiation in the infrared. TCOs are, e.g., widely used in the display industry. To achieve the perfect coatings needed for electronic devices, these are commonly applied using costly vacuum processes at high temperatures. Vacuum processes, on account of the high costs involved and high processing temperatures, are obstructive for an application involving textiles. Accepting that heat-reflecting textile membranes demand less perfect coatings, a wet chemical approach has been followed here when producing transparent heat-reflecting coatings. Commercially available TCOs were employed as colloidal dispersions or nanopowders to prepare sol-gel-based coating systems. Such coatings were applied to textile membranes as used for architectural textiles using simple coating techniques and at moderate curing temperatures not exceeding 130 °C. The coatings achieved about 90% transmission in the VIS spectrum and reduced near-infrared transmission (at about 2.5 µm) to nearly zero while reflecting up to 25% of that radiation. Up to 35% reflection has been realized in the far infrared, and emissivity values down to ε = 0.5777 have been measured.
Cleanable bag filter : comparisons of different testing methods of ageing of filter materials
(2019)
Cleanable bag filters are used to separate dust and other airborne particulate systems. Due to typical process conditions, they are subject to thermal, chemical and mechanical stress during use. The main objective of the IGF project no. 18307 "Investigation of the chemical and thermal degradation of cleanable filter media and improvement of their resistance by surface modification", was the development of a valid test method which can reproduce degradation caused by high temperatures and aggressive chemical atmospheres in a practice-oriented but time-saving manner. Within the IGF project, 2 accelerated ageing methods were applied, both of which have the decisive advantage of investigating damage in the gas phase. Many resistances of filter materials are otherwise carried out by immersing the materials in a mostly liquid damage medium at a defined temperature. These resistances are difficult to transfer ageing in the gas phase.
Abreinigbare Schlauchfilter kommen zur Abscheidung von Stäuben sowie staubförmigen Substanzen zum Einsatz. Aufgrund typischer Prozessbedingungen unterliegen sie während ihres Einsatzes thermischer, chemischer und mechanischer Beanspruchung. Das IGF-Projekt Nr. 18307 "Untersuchung der chemischen und thermischen Degradation von abreinigbaren Filtermedien und Verbesserung deren Beständigkeit durch Oberflächenmodifikation" hat mehrere Prüfmethoden verglichen.
Es wird eine Möglichkeit zur Quantifizierung der Schädigung von Geweben bei der Martindale-Flachscheuerung vorgestellt, die eine interessante Möglichkeit darstellt, vergleichende Untersuchungen durchzuführen, auch wenn die Gewebe nicht bis zu einem Fadenbruch gescheuert werden. Die Untersuchungen deuten außerdem eine Skalierbarkeit der Scheuerversuche bei unterschiedlichen Anpressdrücken an. Sollte sich diese Beobachtung in weiteren Untersuchungen bestätigen, würde dies eine grundlegende Vereinfachung der Scheuerprüfung für verschiedene Anwendungen bedeuten.