1,720,980 research outputs found
Hydrorepellent finishing of cotton fabrics by chemically modified TEOS based nanosol
No full textHydrorepellency was conferred to cotton fabrics by an hybrid organic-inorganic finishing via sol-gel. The nanosol was prepared by co-hydrolysis and condensation of tetraethoxysilane (TEOS) and 1H,1H,2H,2H-fluorooctyltriethoxysilane (FOS), or hexadecyltrimethoxysilane (C16), as precursors in weakly acid medium. The application on cotton was carried out by padding with various impregnation times, followed by drying and thermal treatment, varying the FOS add-on from 5 till 30 % on fabric weight or C16 add-on from 5 to 10 %. Treated samples were tested in terms of contact angles, drop absorption times, washing fastness and characterized by SEM, XPS and FTIR-ATR analyses. In the case of FOS modified nanosol applied with an impregnation time of 24 h or C16 modified nanosol, water contact angles values very close or even higher than 150° were measured, typical of a superhydrophobic surface. The application of the proposed sol-gel process yielded also a satisfactory treatment fastness to domestic washing, in particular for FOS modified nanoso
Cotton and polyester textiles finishing by sol-gel technique
No full textCurrent efforts of research in the field of textile materials are focused on surface functionalization, by innovative and cost effective processes, to obtain products with new or improved properties and high added value that can widen their industrial application. The interest is focused on flame retardancy, UV-protection, resistance to weathering and microbiological attack, super-hydrophobicity and soil resistance. High finishing durability, high degree of homogeneity and superior chemical-physical properties coupled with a reduction of harmful compounds in textile finishing industry can be reached by the application of an hybrid inorganic-organic coating by sol-gel techniques[1-3]. The aim of this work is to confer a hydrophobic behaviour to cotton and polyester fabrics depositing a modified silica based film by sol-gel technique. Sol gel coatings were prepared mixing tetraetoxysilane-based sols with low amounts of hydrophobic additives (n-propyltrimethoxysilane, hexadecyltrimetoxysilane, 1H,1H,2H,2H–Fluorooctyltriethoxysilane). Moreover a LTP, low temperature plasma, pre-treatment was carried out on fabrics to improve the sol gel coating adhesion and fastness. Treated fabrics were characterized by SEM, FTIR and XPS while their wettability was evaluated by measuring the water contact angle. Best results were obtained with a TEOS/FOS combination (θ=148°) for polyester and TEOS/C16 for cotton (θ=140°). The enhanced coating adhesion, due to plasma surface activation, was confirmed by abrasion and washing fastness tests
Hydrophobic sol-gel finishing for textiles: Improvement by plasma pre-treatment
No full textThe surface of cotton (COT) and polyester (PET) fabrics was modified to create a water-repellent finishing by depositing
a modified silica-based film using the sol-gel technique. TEOS (tetraethoxysilane)-based physically modified sols with 2%
and 11% on weight fabric (o.w.f.) of hydrophobic additives were tested. N-propyltrimethoxysilane (C3), hexadecyltrimethoxysilane
(C16) and 1H,1H,2H,2H-fluorooctyltriethoxysilane (FOS) were investigated as additives.
Furthermore, a low-temperature plasma pre-treatment was used to activate the COTand PET fabric surface to improve
the sol-gel coating adhesion, resistance to abrasion and fastness to washing stresses.
A complete chemical/morphological (Fourier transform infrared, X-ray photoelectron spectroscopy, scanning electron
microscopy) and physical characterization (abrasion and air permeability test) of treated samples was carried out. High
values of y (around 140) on PET and COT samples were obtained with all additives used (C3, C16 and FOS) even at a
low concentration (2%). Due to plasma pre-treatment, interesting water-repellent properties were achieved for PET
(y1⁄4148) treated with TEOS/FOS molar ratio 0.63 and for COT (y1⁄4140) with TEOS/C16 molar ratio 0.63. The
enhanced coating adhesion, due to plasma surface activation, was confirmed by abrasion and washing tests
Nanofibre per elettrofilatura di polimeri naturali
No full textVengono presentati i fondamenti dei processi di elettrofilatura per l'ottenimento di nanofibre. Successivamente si riportano i risultati di esperienze di elettrofilatura di soluzioni di cheratina di lana in miscela con PEO. Le miscele sono state caratterizzate con misure di conducibilità e viscosità, mentre le nanofibre ottenute sono state caratterizzate con misure di microscopia
Thermal and structural characterization of poly(ethylene-oxide)/keratin blend films
No full textBlends of poly(ethylene oxide) (PEO) and keratin were prepared with the aim of obtaining bio-compatible materials suitable for film and fibre production. Aqueous keratin solutions, prepared by keratin extraction from wool with urea, m-bisulphite and sodium dodecyl sulphates (SDS), filtration and dialysis, were added with different amounts of PEO and solid films were prepared by casting. The addition of SDS prevents protein aggregation.
Morphological, thermal and spectroscopic analysis of the films pointed out that keratin hinders the PEO crystallization process, since a progressive decrease in the size of PEO spherulites is observed and the melting point and the related enthalpy decrease with increasing the keratin content. On the other hand, according to thermal and spectroscopic investigations. PEO seems to interfere with the keratin self-assembling giving the protein a different thermal behaviour
Oxygen Plasma Treatment to Reduce DyeingTemperature of Wool Fabrics and Characterization of their Physical, Mechanical and Handle Properties
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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