Compressive behaviour of a tire recycled steel and textil fiber concrete subjected to fire

The use of rubber aggregates, steel and textile fibres recycled from tires in concrete is a solution that it is being studied by several authors around the world. A few works have been carried out at room temperature but very scarce at high temperatures. This paper presents the results of a research with the aim to evaluate the behaviour at high temperatures of a concrete made with different amounts of recycled textile and steel fibres from tires. The study considered five concrete compositions, with the same water/cement ratio (W/C=0.43), differing only in the type and quantity of fibers incorporated in the mixture. Thus, a reference composition (0% fiber), two compositions with 30 and 70kg/m3 of steel fibers and a composition with 2 and 4kg/m3 of textile fibers from tires were tested. The concrete was tested for a load level of 0.5fcd and different maximum temperature levels (20, 300, 500 and 700ºC).

High strength, high modulus fibers by pyrolysis of polymeric fibers

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Novel nanocomposite fibres for technical textile applications : synthesis and characterisation of poly(m-xylene adipamide) montmorillonite nanocomposites

Technical textiles, based on advanced polymeric materials, are an important segment of the synthetic textile market. This area has seen considerable growth in recent times, now accounting for almost 25% of all manufactured synthetic fibres, and has driven the recent development of a range of specialist high performance polymer fibres that are stronger, lighter or have improved heat and fire resistance. However, the increasing size of the market has highlighted the need for materials that have improved performance whilst maintaining low manufacturing costs. These factors have resulted in a change in how new specialty fibres are developed and the emphasis in this field is now on the upgrading or improving of the properties of commodity (conventional) fibres by modifying their properties to suit specific applications.

This paper will describe our work on preparing novel polymer nanocomposite fibres by the addition of clay nanoparticles during melt extrusion. The effect of the nanoparticles on the processing of the fibres and the result on the physical morphology and mechanical properties will be described.

Novel nanocomposite fibres for technical textile applications

Technical textiles, based on advanced polymeric materials, are an important segment of the synthetic textile market. This area has seen considerable growth in recent times, now accounting for almost 25% of all manufactured synthetic fibres, and has driven the recent development of a range of specialist high performance polymer fibres that are stronger, lighter or have improved heat and fire resistance. However, the increasing size of the market has highlighted the need for materials that have improved performance whilst maintaining low manufacturing costs. These factors have resulted in a change in how new specialty fibres are developed and the emphasis in this field is now on the upgrading or improving of the properties of commodity (conventional) fibres by modifying their properties to suit specific applications.

This paper will describe our work on preparing novel polymer nanocomposite fibres by the addition of clay nanoparticles during melt extrusion. The effect of the nanoparticles on the processing of the fibres and the result on the physical morphology and mechanical properties will be described.

Anthraquinones from the Fungus Dermocybe sanguinea as Textile Dyes

This study is based on the multidiciplinary approach of using natural colorants as textile dyes. The author was interested in both the historical and traditional aspects of natural dyeing as well as the modern industrial applications of the pure natural compounds. In the study, the anthraquinone compounds were isolated as aglycones from the ectomycorrhizal fungus Dermocybe sanguinea. The endogenous beta-glucosidase of the fungus was used to catalyse the hydrolysis of the O-glycosyl linkage in emodin- and dermocybin-1-beta-D-glucopyranosides. The method, in which 10.45 kg of fresh fungi was starting material, yielded two fractions: 56.0 g of Fraction 1 (94% of the total amount of pigment,) consisting almost exclusively of the main pigments emodin and dermocybin, and 3.3 g of Fraction 2 (6%) consisting mainly of the anthraquinone carboxylic acids. The anthraquinone compounds in Fractions 1 and 2 were separated by one- and two-dimensional thin-layer-chromatography (TLC) using silica plates. 1D TLC showed that neither an acidic nor a basic solvent system alone separated completely all the anthraquinones isolated from D. sanguinea, in spite of the variation of the rations of the solvent components in the systems. Thus, a new 2D TLC technique was developed, applying n-pentanol-pyridine-methanol (6:4:3, v/v/v) and toluene-ethyl acetate-ethanol-formic acid (10:8:1:2, v/v/v/v) as eluents. Fifteen different anthraquinone derivatives were completely separated from one another. Emodin, physcion, endocrocin, dermolutein, dermorubin, 5-chlorodermorubin, emodin-1-beta-D-glucopyranoside, dermocybin-1-beta-D-glucopyranoside and dermocybin, and five new compounds, not earlier identified in D. sanguinea, 7-chloroemodin, 5,7-dichloroemodin, 5,7-dichloroendocrocin, 4-hydroxyaustrocorticone and austrocorticone, were separated and identified on the basis of their Rf-values, UV/Vis spectra and mass spectra. One substance remained unidentified, because of its very low concentration. The anthraquinones in Fractions 1 and 2 were preparatively separeted by liquid-liquid partition, with isopropylmethyl ketone and aqueous phosphate buffer as the solvent system. Advantage was taken of the principle of stepwise pH-gradient elution. The multiple liquid-liquid partition (MLLP) offered an excellent method for the preparative separation of compounds, which contain acidic groups such as the phenolic OH and COOH groups. Due to their strong aggregation properties, these compounds are, without derivatization, very difficult to separate on a preparative scale by chromatographic methods. By the MLLP method remarkable separations were achieved for the components in each mixture. Emodin and dermocybin were both obtained from Fraction 1 in a purity of at least 99%. Pure emodin and dermocybin were applied as mordant dyes to wool and polyamide and as disperse dyes to polyester and polyamide, using the high temperature (HT) technique. A mixture of dermorubin and 5-chlorodermorubin was applied as an acid dye to wool. In these experiments, synthetic dyes were used as references. Experiments were also performed using water extract of the air-dried fungi as dye liquor for wool and silk. The main colouring compounds in the crude water extract were emodin and dermocybin, which indicated that the O-glycosyl linkages in emodin- and dermocybin-1-beta-D-glucopyranosides were broken by the beta-glucosidase enzyme. Apparently, the hydrolysis occurred during the drying of the fungi and during the soaking of the dried fruit bodies overnight when preparing the dyebath. The colour of each dyed material was investigated in terms of the CIELAB L*, a* and b* values, and the colour fastness to light, washing and rubbing was tested according to the ISO standards. In the mordant dyeing experiments, emodin dyed wool and polyamide yellow and red, depending on the pH of the dyebath. Dermocybin gave purple and violet colours. The colour fastness of the mordant-dyed fabrics varied from good to moderate. The fastness properties of the natural anthraquinone carboxylic acids on wool were good, indicating the strength of the ionic bonds between the COO- groups of the dyes and the NH3+ groups of the fibres. In the disperse dyeing experiments, emodin dyed polyester bright yellow and dermocybin bright reddish-orange, and the fabrics showed excellent colour fastness. In contrast, emodin and dermocybin successfully dyed polyamide brownish-orange and wine-red, respectively, but with only moderate fastness. In industrial dyeing processes, natural anthraquinone aglycone mixtures dyed wool and silk well even at low concentrations of mordants, i.e. with 10% of the weight of the fibre (owf) of KAl(SO4)2 and 1 or 0.5% owf of other mordants. This study showed that purified natural anthraquinone compounds can produce bright hues with good colour-fastness properties in different textile materials. Natural anthraquinones have a significant potential for new dyeing techniques and will provide useful alternatives to synthetic dyes.

Synthetic fibres for fishing gear

A variety of synthetic fibres are at present in use as fishing gear material, the earliest one being the polyvinyl chloride group introduced for traps in 1936 (von. Brandt 1957). Since then synthetic fibres became increasingly popular among the advanced fishing nations of the world. The latest synthetic fibre which has been successfully used in fishing is polypropylene developed in Italy in 1954.

Flexural performance of fibre reinforced concrete made with steel and synthetic fibres

The ductility of concrete made with commercially available steel and synthetic fibres has been investigated. Flexural stress–deflection relationships have been used to determine: flexural strength, flexural toughness, equivalent flexural strength, and equivalent flexural strength ratio. The flexural toughness of concrete was found to increase considerably when steel and synthetic fibres were used. However, equal dosages of different fibres did not result in specimens with the same flexural toughness. Flexural toughness differences of almost 35 J existed even at the same fibre dosage. This also resulted in considerable differences in the minimum required ground supported slab thickness.