Ozone fabric

Oxygen Index Test. The oxygen iadex test (OI) is based on the minimum oxygen concentration that supports combustion of various textile materials (51—53). A fabric which would not bum ia pure oxygen would have an OI of 1.0. One which would just barely bum ia an atmosphere of 20% oxygen and 80% nitrogen would have an OI of 0.20. The higher the OI of a given fabric, the less flammable it is and vice versa. The OI values of various untreated fabrics are Hsted ia Table 2.  [c.487]

Fabric Oxygen iadex  [c.487]

Fine and Hollow Fibers. Controlling and designing the geometry, fineness or denier, and porosities of fibers (and occasionaUy of yams) have led to novel and high technology textile products for diverse appHcations. HoUow fibers derived from regenerated ceUulose or from synthetic fibers have been used in the development of artificial body organs such as the kidney, pancreas, and lung (see Hollow-FIBERMEMBRANEs). HoUow fibers have also frequently been employed to increase the insulation value of garments due to the benefits of the air trapped inside the fiber cavity. A variety of ultrafine fibers, ranging in tex (denier) from as Httle as 0.0011 (0.01) up to 0.011 (0.1) have been commercialized (primarily in Japan) to impart various surface characteristics that change fabric hand and appearance. Because spinning ultrafine fibers directly is not technically feasible, such fibers are produced by spinning bicomponent or biconstituent polymer mixtures, highly stretching them to form ultrafine deniers, and extracting or otherwise removing the  [c.70]

High power lasers have impressive capabiHties for cutting both metallic and nonmetalHc materials. The cutting rates can be increased by the presence of gases. Typically oxygen is used but other gases have sometimes been employed. A jet of oxygen or aH is blown on the workpiece at the position where the beam strikes it. The exothermic chemical reaction with the oxygen can greatly increase the cutting rate for reactive materials. Laser cutting is widely used in many practical appHcations, such as cutting titanium in the aerospace industry, cutting steel [12597-69-2] plates in the automotive industry, and cutting fabric in the garment industry.  [c.13]

Durability. Flex endurance is correlated with water-vapor permeabiUty, s vand man-made leathers have the best durabiUty. Scratch resistance is inversely correlated with water-vapor permeabiUty, and vinyl-coated fabric has the best performance. DurabiUty for aging depends on the polymer used for the coating layer, because the polymer of the substrate fabric is generally more durable than that of the layer. Vinyl-coated fabrics are sufficiently durable. The durabihties of urethane-coated fabrics and man-made leathers vary to a large extent depending on the polyurethanes used because the physical and chemical properties of segmented polyurethanes markedly vary according to the segment type (see Urethane polymers). Polyurethanes degrade because of water, oxygen, NO, SO, and other chemical substances. Hydrolysis, degradation by H2O, is the most important factor in the durabiUty of polyurethanes, and it depends on the soft segments used. Soft segments are classified into three groups polycarbonates, polyethers, and polyesters, and have better resistance to hydrolysis in this order. The components of a polyurethane can be selected according to the end use. Polyesters and polyethers are mainly used polycarbonates are used for items especially requiring durabiUty, such as in automobiles.  [c.92]

The limiting oxygen index (LOI) of novoloid materials varies with the particular stmcture (fiber, felt, fabric) being evaluated it is generally in the 30—34% range. By comparison, aramid fiber has a LOI of 28—31 and wool of 24. When exposed to flame, novoloid materials do not melt but gradually char until completely carbonized. The high strength of the phenolic char results in the fiber retaining its original fiber stmcture, and the chat effectively absorbs heat from the materials. When novoloid products are exposed to flame, the products of combustion are principally H2O, CO2, and carbon char. Smoke emission is minimal, less than that of any other organic fiber.  [c.309]

It has good stabihty and can be used in formulations with many compounds without serious loss of active oxygen. The monohydrate is made by dehydration of the tetrahydrate. The active oxygen contents of the tetrahydrate and monohydrate are 10.5% and 16.0%, respectively. The tetrahydrate is the perborate salt most commonly used in bleaching appHcations (77). However, as consumer trends move toward more concentrated products, monohydrate is growing in demand because of its higher AO content (78). Because sodium perborate has much greater stabihty than sodium hypochlorite, it can be formulated into a wide variety of products, including detergents. In the United States, perborates are used in all-fabric bleach formulations, detergents, denture cleaners, tooth powders, and other special cleaners. Sodium perborate is used extensively in Europe in detergent formulations.  [c.146]

The appHcation procedures of reduction with caustic and reducing agents such as sodium dithionite (hydrosulfite) and subsequent oxidation are identical to those for vat dyes. The principal difference is that indigo is appHed by a "dipping" method. When ceUulose is dipped into reduced indigo the fiber quickly (within seconds) absorbs indigo and reaches an equiHbrium. At this stage the fiber is removed from the indigo vat and atmospheric oxygen reforms the insoluble indigotin in the fiber. The fiber is then re-immersed in the indigo vat, more leuco is absorbed, and the process repeated until the desked depth of shade is obtained. Each time the fabric is dipped there is more or less the same incremental increase in depth of shade.  [c.358]

Some algae produce dense, fibrous mats in sunlit areas. The mats act as passive corrosion sources. Differential concentration cells may be established. Corrosive anaerobes may grow beneath algal mats. Additionally, high concentrations of dissolved oxygen can be created by vigorously growing algae. In at least one case, dissolved oxygen concentrations measured near cooling water intakes at a steel mill were as high as 10 ppm, well above the calculated oxygen saturation concentration at inlet temperature and pressure. Oxygen concentration fell at night when algae growth stopped. Corrosion rates measured with electric polarization devices followed a similar diurnal cycle.  [c.124]

Globular proteins exist in an enormous variety of three-dimensional structures, but nearly ail contain substantial amounts of the a-helices and /3-sheets that form the basic structures of the simple fibrous proteins. For example, myoglobin, a small, globular, oxygen-carrying protein of muscle (17 kD, 153 amino acid residues), contains eight a-helical segments, each containing 7 to 26 amino acid residues. These are arranged in an apparently irregular (but invariant) fashion (see Figure 5.7). The space between the helices is filled efficiently and tightly with (mostly hydrophobic) amino acid side chains. Most of the polar side chains in myoglobin (and in most other globular proteins) face the outside of the protein structure and interact with solvent water. Myoglobin s structure is unusual because most globular proteins contain a relatively small amount of a-helix. A more typical globular protein (Figure 6.23) is bovine ribonuclease A, a small protein (14.6 kD, 129 residues) that contains a few short helices, a broad section of antiparallel /3-sheet, a few /3-turns, and several peptide segments without defined secondary structure.  [c.179]

Flammability. Flammability of polymeric materials is measured by many methods, most commonly by the limiting-oxygen-index test (ASTM D2863), which defines the minimum oxygen concentration necessary to support combustion, or the UL 94 vertical-bum test, which measures the bum length of a fabric. Most polyolefins can be made fire retardant using a stabilizer, usually a bromine-containing organic compound, and a synergist such as antimony oxide (23). However, the required loadings are usually too high for fibers to be spun. Fire-retardant polypropylene fibers exhibit reduced light and thermal resistance. Commercial fire-retardant polyolefin fibers have just recentiy been introduced, but as expected the fibers have limited light stabiHty and  [c.314]

Poly[2,2 -(y -phenylene)-5,5 -bisbenzimidazole] was chosen as the most promising candidate for further development as a fibrous material. Under the terms of an Air Force contract. Du Pont was able to spin fibers from both dimethyl sulfoxide and dimethyl acetamide solutions to form relatively strong, thermally stable fibers. In 1963, an Air Force contract was awarded to Celanese Research Co. for the development of a manufacturing process for the scale-up of PBI production. PBI fiber of tenacities 0.31-0.44 N/tex (3.5-5.0 gf/den) were produced in sufficient quantity for large-scale evaluation. The fiber was discovered to have a soft hand in addition to possessing a high degree of nonflammability. In the limited oxygen index (LOI) test, the concentration of oxygen requited for sustained, steady-state burning was 41%. A new development program was started at Celanese with binding from NASA and the Air Force to develop a flight suit material, fabrics for fatigues worn in space capsules, and utiHty equipment such as ropes and bungee cords.  [c.67]

When the water phase of the drilling fluid contains substantial amounts of electrolyte, salt water clays such as attapulgite and sepiohte are added to raise viscosity. Attapulgite is used solely for its suspending quaUties. It has a fibrous texture and crystalline, needle-like, hydrated magnesium siUcate particles. The crystal stmcture is that of a double chain of siUcon and oxygen linked by magnesium and calcium (36). Attapulgite clays iacrease viscosity regardless of the composition of the makeup water. This abiUty does aot depead oa hydratioa, but rather oa the exteat to which the buadles of aeedles are brokea up by a shearing force.  [c.178]

The mechanism of bleaching of hydrogen peroxide is not well understood. It is generally beUeved that the perhydroxyl anion (HOO ) is the active bleaching species since both the concentration of this anion and the rate of the bleaching process increase with increasing pH (70). Whereas the role of free-radical reactions in the bleaching process remains speculative, mechanisms involving heavy-metal cataly2ed reactions are generally undesirable, since they often reduce the effective bleaching because of the rapid loss of peroxide and may also result in fabric damage if the metal is entrapped in the fabric (150). Hydrogen peroxide and other peroxygen compounds can destroy double bonds by epoxidation. This involves addition of an oxygen atom across the double bond usually followed by hydrolysis of the epoxide formed to 1,2-diols under bleaching conditions.  [c.150]

Another useful reaction of cotton ceUulose occurs with an ioni2ed atmosphere. This is essentiaUy a surface reaction. Glow discharge treatment of cotton yam in air increases water absorbency and strength (69), and surface-dependent properties of cotton fabric are drasticaUy changed by exposure to low temperature—low pressure plasma generated by radio-frequency radiation (70). Because only a few extremely high energy electrons (10 to 15 eV) are generated, ambient temperature is maintained in the chamber. Light microscopy indicates a smoother surface, although scanning electron microscopy shows no change from native cotton. Spectral changes show some oxidation of the cotton, a decreased carbon-to-oxygen ratio. Eree radicals similar to those from Co radiation are formed. In addition, highly charged species are also formed, aUowing such usuaUy inert monomers as ben2ene to be polymeri2ed onto the cotton there is great capacity for bond cleavage. Plasma treatment gives an increased rate of wetting and drying and produces a  [c.315]

Suppliers. Cyanine dyes are used primarily for specialty purposes photographic sensitizers and desensitizers, laser dyes, infrared imaging, and certain medicinal appHcations. Because of this, their manufacture is limited to significantly smaller quantities than for fabric dyes or other widely used coloring agents. However, the photographic, laser, and medicinal uses place high demands on the degree of purity required, and the reproducibiHty of synthetic methods and purification steps is very important. SuppHers of cyanine dyes include manufacturers of other specialty organic and photographic chemicals Aldrich Chemical Company (Milwaukee, Wis.), Eastman Organic Chemicals (Rochester, N.Y.), Japanese Institute for Photosensitizing Dyes (Okayama, Japan), Molecular Probes (Eugene, Oreg.), NKDyes (Japan), Pfaltz and Bauer (Stamford, Coim.), and Riedel deHaen (Kadsmhe, Germany). More importantiy, these firms provide sources of generally usefiil reagents which, in two or three synthetic steps (12), lead to many of the commonly used cyanine dyes.  [c.400]

Sensitizing dyes aie used primarily for specialty purposes photographic sensitizers, electrophotographic sensitizers, laser dyes, infrared (optical disk, etc) imaging, and certain medicinal appHcations. Because of this, their manufacture is limited to significantly smaller quantities than for fabric dyes or other widely used coloring agents. However, the photographic, laser, and medicinal uses place high demands on the degree of purity required, and the reproducibihty of synthetic methods and purification steps is very important. SuppHers of cyanine dyes include manufacturers of other specialty organic and photographic chemicals Aldrich Chemical Co. (Milwaukee, Wisconsin), Eastman Fine Chemicals (Rochester, New York), Japanese Institute for Photosensitizing Dyes (Okayama, Japan), Molecular Probes (Eugene, Oregon), NKDyes (Japan), Pfaltz and Bauer (Stamford, Coimecticut), Riedel deHaen (Kadsmhe, Germany), and H. W. Sands. More importandy, these firms provide sources of generally usefiil reagents that, in two or three synthetic steps, lead to many of the commonly used sensitizers.  [c.438]

Bleach systems oxidize proteinaceous stains on fabric, often making the stains more difficult to remove. Detergent proteases can counteract this negative effect of the bleach system. The most commonly used bleach systems in detergents consist of sodium perborate [7632-04-4] plus an activator such as tetraacetylethylenediarnine [10543-57-4] (T A ED). Perborate releases hydrogen peroxide [7722-84-1/, H2O2, which combines with the activator to form a peroxycarboxyhc acid. Most detergent proteases are stable during the wash cycle in the presence of such active-oxygen bleach systems. However, storage StabHity in detergents containing bleach may be a problem with the estabHshed detergent proteases. New protein-engineered proteases introduced onto the market replace the most bleach-sensitive amino acid, ie, methionine close to the active site, with other amino acids not sensitive toward oxidation. This slight change in the molecular stmcture significantly increases the storage stabHity in detergents containing bleach (42) (Pig. 7). Chlorine bleach [7681-52-9] (sodium hypochlorite), NaOCl, is not incorporated into laundry detergents themselves, but is used separately in some parts of the world as an additive. In normal wash concentrations above 200 ppm it quickly oxidizes the enzymes, resulting in loss of protease activity.  [c.294]

This includes organic fibrous materials on a cellulose base such as paper, pressboard, cotton, cotton cloth and natural silk etc., impregnated with lacquers or immersed in an insulating liquid. The impregnation or immersion ensures that the oxygen content of the air does not affect  [c.221]

FIGURE A15.3 Oxygen saturation curve for Hb in the form of Fversus pO, assuming n =  [c.497]

See pages that mention the term Ozone fabric : [c.65]    [c.333]    [c.56]    [c.432]    [c.446]   
Fundamentals of air pollution (1994) -- [ c.132 ]