1,721,025 research outputs found
Tessili conduttivi (Conductive textiles)
No full textThe polymerisation of pyrrole on a textile substrate using a polyester fabric was investigated. Polymerisation occurs via the formation of cationic radicals following the oxidation of the monomer. The cations formed are coupled to form oligomers which are absorbed on to the surface of the substrate. The conductive properties of the resulting fabric were tested using a voltmeter to measure the surface resistance. The physico-mechanical and thermal properties of the fabric were analysed. A fabric of this type has many possible uses in electronics, reinforcement, protective clothing and military uses, since it combines the physico-mechanical properties of the substrate with the electrical properties of the polypyrrole
Performances and properties of intrinsic conductive cellulose-polypyrrole textiles
No full textIn the past, semiconductive textiles including yarns and fabrics, have been produced by incorporating conductive fillers (particularly carbon, metal powder or conductive polymers) into the fibre structure or by coating fibres with metals or thin films of conductive polymers. Incorporation of large amounts of conductive fillers results in a deterioration of mechanical properties and processing problems of the fibres. Conductive polymers, such as polypyrrole (Ppyr), deposited on textile substrates, are highly susceptible to oxidation and abrasion. Recent research carried out in our laboratories, shows that polypyrrole can be embedded in natural and man made cellulose-based fibres, such as cotton, viscose, cupro and lyocell, by means of internal polymerisation taking place in the amorphous region of the fibres. In this work, pyrrole was applied by simple finishing process at room temperature from an aqueous solution of the monomer that penetrates into the fibre similarly to a non-reactive dye. Subsequent polymerisation caused its permanent insolubility in the internal fibre structure, leading to high levels of fastness to washing and to light exposure, without significant modification of the mechanical properties. This low cost technological application is of particular interest for developing new technical apparel, such as antistatic fabrics for work clothing, sportswear, heating and cooling equipment, etc
Electrically conductive textiles
No full textWool fabrics with conventional properties and performances were transformed into electrically conductive textiles by coating the fibers with polypyrrole, a conductive polymer. The fabrics were treated with an aqueous solution containing the monomer pyrrole and a catalyst of polymerization, iron chloride hexahydrate, in order to achieve the deposition of a thin polymeric conductive layer on the surface of the fibers. The influence of the treatment on the characteristics of the original fabrics was evaluated by measuring physical, mechanical and thermal properties of untreated and treated samples; the conductivity was evaluated by measuring the surface electrical resistance. The results demonstrate that the process gives conductive properties without significantly modifying the properties of the original textiles, (apart from the color) thus opening new perspectives for their utilization. Moreover, the treatment does not seem to be influenced by the nature of the substrate; its application to any textile fiber should therefore be suitable
Intrinsically conducting cellulose textiles
No full textElectrically conductive textiles based on polypyrrole thin films deposited on fibre substrates are highly susceptible to oxidation and wear abrasion. Recent research carried out in our laboratories shows that polypyrrole can be embedded in natural and man rnade cellulose-based fibres, such as cotton, Viscose, Cupro and Lyocell, by means of internal polymerisation taking place in the amorphous region of the fibres. In this work, pyrrole was applied by simple finishing process at room temperature from an aqueous solution of the monomer
that penetrates into the fibre similarly to a non reactive dye. Subsequent in situ polymerisation caused its permanent insolubility in the intemal fibre structure, leading to good fastness to washing and to light exposure, without significant modification of the mechanical properties of the fibres. To prevent the atmospheric oxidation of the samples, silicon-based coatings wereapplied after polymerisation. This low cost technological application is of particular interest for developing new technical textiles such as antistatic fabrics for work clothing, sportswear and apparel, heating and cooling equipment , etc
Recupero e valorizzazione degli scarti di lana: caratterizzazione di membrane di acetato di cellulosa e cellule corticali
No full textChemical synthesis and deposition of conducting polypyrrole on textile materials
No full textSeveral methods have been proposed to improve the electrical properties of textiles made of fibres with poor electrical conductivity because of the large number of potential applications that can be successfully developed with conducting textiles in the technical fields (e.g. protective clothing, automotive fabrics, building covering). Polypyrrole (PPy) deposition seems one of the most promising way to coat fibres with a light and flexible conducting layer. The deposition process has been carried out by in situ chemical oxidative polymerisation of pyrrole (Py) in water. Suitable oxidising agents are ammonium persulfate (APS) or ferric chloride (FC)
Process Optimization and Industrial Scale-Up of Chitosan Based Anti-Felting Treatments of Wool
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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
Composite biomaterials from fibre wastes: Characterization of wool-cellulose acetate blends
No full textHistological components from wool fibre wastes were extracted by an enzyme-ultrasonic treatment, characterised by SDS-PAGE and successively included, in different proportions, in a cellulose acetate matrix to make composite film-forming blends, suitable for film casting and filament spinning. Chemical, thermal and mechanical properties were characterised by FT-IR spectroscopy, DSC, TGA and tensile tests; surface and internal morphology were investigated by SEM and light microscopy. Cortical cells were partially degraded during extraction from wool, but the degradation extent does not depend on the enzyme amount used which, instead, showed an influence on the yield of the cell production. Cellulose acetate-wool cell blends are capable of forming smooth translucent composite films with acceptable tensile, thermal and water absorption properties. Extrusion in the form of filament resulted in a general orientation of the cortical cells in the direction of the fibre axis.
Application for keratin-cellulose based bio-composite materials can be envisaged as compostable packaging, disposables, agricultural films, textile fibres with novel properties such as improved fire resistance, moisture regain, dyeing performances, and colour effects, handle and look
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