Stain repellency

Due to a waxy component in the cell wall these organisms are difficult to stain with ordinary stain solutions, the hydrophobic nature of the wall being stain repellent however, if the bacterial smear on the slide is warmed with the stain, the cells are dyed so strongly that they are not decolorized by washing with dilute acid, hence the term acid-fast. Many bacterial spores exhibit the phenomenon of acid fastness. 

The PFAS are used in the production of stain-repelling agents, and fluoropolymers, such as Teflon, pesticides, lubricants, paints, medicines, and fire-fighting foams. PCNs are used in cable insulation, wood preservatives, engine oil additives, electroplating masking... 

PFCs comprise a large group of compounds characterized by a fully fluorinated hydrophobic linear carbon chain attached to one or more hydrophilic head. PFCs repel both water and oil, and are therefore ideal chemicals for surface treatments. These compounds have been used for many industrial applications including stain repellents (such as Teflon), textile, paints, waxes, polishes, electronics, adhesives, and food packaging [1]. 

The treatment of textiles with organohydrosiloxanes with phenyl, ethyl and butoxyl groups in the backbone helps to give them both waterproof and stain-repellent properties. An oligomer of the common formula ... 

The polycondensate of Fomblin and 3-(trimethoxysilyl)propyl amine prepared by Moore [3] was used to provide resistance to water, oil, and stain repellency to a substrate or fabric. De Dominicis [4] used mono and difunctional perfluoropolyether phosphates and amidosilane derivatives as antistaining agents for ceramic materials. 

FC finishes alone do not sufficiently prevent coffee, tea and other foodstuffs from dyeing nylon and wool carpets with coloured spots, especially when these liquids are not quickly removed. Stain blocking for these carpets is achieved by the combination of FC products with syntans. The latter are also used for wet fasmess improvement of acid dyed nylon (see Chapter 13). Stain repellency is promoted by hydrophobic finishes, mostly fluorocarbons, but with decreasing costs also by... 

Fluorochemical Stain Repellent and Dry Soil Resistant Finish for Fabrics Aqueous Application... 

Fluorochemical Stain Repellent Water Repellent Finish for Outerwear,... 

Alguard NS. [Allied Colloids] Sul-fonated aromatic condensate stain repellent for nylon carpet... 

GranguardTG. [Grant Industries] Water, oil and stain repellent for use on synthetic and cellulosic fabrics. 

Separation of PFASs can be performed with eommon stationary phases 5% phenyl substimted methylpolysiloxane (Shoeib et al. 2005), although more polar capillary columns are required for FTOHs (Jahnke et al. 2007 Shoeib et al. 2008). Shoeib et al. (2009) determined concentrations of PFAS in indoor air from homes and laboratories. N-methyl perfluorooctane sulfonamidoethanol (MeFOSE), widely used as a stain repellent on carpets, was the most abundant in both indoor and outdoor air, followed by N-ethyl perfluorooctane sulfonamidoethanol (EtFOSE). Mean indoor concentrations of MeFOSE and EtFOSE were 2589 and 772 pg m , respectively. These concentrations were approximately 100 times higher than their outdoor values. PFAs in indoor air from office were evaluated by Jahnke et al. (2007), obtaining values for MeFOSE and EtFOSE of 727 and 305 pg m , respectively. 

Fluorocarbons are known to introduce durable water and oil repellency (DWOR) and, as such, they are apphed in water- and stain-repellent fabrics for apparel. The combination of water and oil repellency is a typical behavior of fluorocarbon products. In the past, finishes based on C8 fluorocarbons (eight carbon atoms in the structure) were mainly used. However, concerns arose associated with these C8 fluorocarbons, more specifically with respect to PFOA (perfluorooctanoic acid or pentadecafluorooctanoic acid) and PFOS (perfluorooctane sulphonate or heptadecafluoro-l-octanesulfonic acid). 

The incidence of chromate allergy in footwear dermatitis varies in different studies. Trivalent chromate is used hence, the sensitization potential is low. Nevertheless, chromate allergy should always be considered in shoe dermatitis and possibly even as a factor in hand dermatitis due to wearing leather gloves. Chromate is used in leather for other purposes than tanning, e.g. water-repellent trivalent chromium stearate chloride or stain-repellent trivalent chromium and fluorinated carboxylic acids, or as a dye. In those carrying out tanning, the sensitization risk is increased... 

Scotchgard (Patsy O Connell Sherman) Sherman develops a stain repellent for fabrics that is trademarked as Scotchgard. 

There have been some reports of the addition of PTFE to plastic resins to improve their soil and stain repellency and/or barrier properties however, the addition of noncrystalline fluorochemicals is more common for this purpose [43]. 

And then, in 1908, a remarkable new form of cellulose was developed by a Swiss chemist, Jacques Brandenberger, who conceived the idea of a stain-repellent fabric while watching red wine soak into a tablecloth in a restaurant. His efforts to coat linen with a cellulose film resulted only in a brittle sheet, but then he found that the coating could be peeled away from the cloth as a thin flexible transparent film. This became cellophane, first used as a humidor wrapping for cigars. The merits of its impermeability to moisture and contaminants soon became apparent, and it instantly made a huge impact on the food industry. The miraculous nature (as it appeared) of the material was even celebrated in one of Cole Porter s lyrics ... 

Perfluoroalkyl and polyfluoroalkyl substances (PEASs) are persistent organic pollutants with nearly ubiquitous occmrence in environmental samples. PEASs have anthropogenic origins over the period 1951 to 2004, it has been estimated that up to 7300 tons (i.e., 6.6 x 10 kg) of PEASs have been released into the environment [145]. PEASs are used in the manufacture of industrial materials and consmner products. The compounds are characterized by a nonpolar fluorinated hydrocarbon chain with a polar end group, and they exhibit both lipophobic and hydrophobic properties. Principal applications include uses as srufactants, nonstick coatings, and stain repellants. The compoimds are also precursors in the synthesis of fluoroelastomers and fluoropol)uners and are used in the... 

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