Anionic softeners

Schematic orientation of softeners on fibre surfaces, (a) Cationic softener and (b) anionic softener at fibre surface. Non-ionic softener at (c) hydro-phobic and (d) hydrophilic fibre surface. 

Anionic softeners are heat stable at normal textile processing temperatures and compatible with other components of dye and bleach baths. They can easily be washed off and provide strong antistatic effects and good rewetting properties because their anionic groups are oriented outward and are surrounded by a thick hydration layer. Sulfonates are, in contrast to sulfates, resistent to hydrolysis (Fig. 3.3). They are often used for special applications, such as medical textiles, or in combination with anionic fluorescent brightening agents. 

Cationic and anionic softeners may be easily prepared from CNC BASE 500-A. 

Anionic softeners of the substantive type may be prepared as follows ... 

Anionic softener/lubricant for packaged-dyed cotton. 

Anionic softener for fabric finishing can be combined with all types of filling agents softener with stabilizing effects in peroxide bleaching of cotton yarns. 

Lauramine 20A. [Reilly-Whiteman] Anionic softener for textfies. 

Tyner. [Bruce Chem.] Ntmionic, cationic, and anionic softeners. 

Uses Detergent used in detergent applies., nonirritating toiletries, cosmetics, shampoos, liq. soaps anti-irritant for anionics softener Features Med. foaming... 

Oleochemically based softeners are mainly amides of fatty (stearic) acid with polyamines (e.g., diethylenetriamine), in which free amine functions are neutralized with mineral or organic acids. Also, cationic softeners (- quaternary ammonium compounds), such as dis-tearyl dimethylammonium or quaternized esters with tallow acids, are in use. Nonionic softeners are based on esters of stearic acid and ethoxylates of stearic acid or stearyl alcohol. As anionic softeners, sulfonated oils of fatty esters are known. 

A salt originally called sodium hexametaphosphate, with n believed to be 6, is now thought to contain many much larger anion aggregates. It has the important property that it sequesters , i.e. removes, calcium ions from solution. Hence it is much used as a water-softener. 

Ton-exchange systems vary from simple one-column units, as used in water softening, to numerous arrays of cation and anion exchangers which are dependent upon the appHcation, quaHty of effluent required, and design parameters. An Hlustration of some of these systems, as used in the production of deionized (demineralized) water, is presented in Figure 7. 

There are two reasons why the concentration of quaternaries is beheved to remain at a low level in sewage treatment systems. First, quaternaries appear to bind anionic compounds and thus are effectively removed from wastewater by producing stable, lower toxicity compounds (205). Anionic compounds are present in sewer systems at significantly higher concentrations than are cations (202). Second, the nature of how most quaternaries are used ensures that their concentrations in wastewater treatment systems are always relatively low but steady. Consumer products such as fabric softeners, hair conditioners, and disinfectants contain only a small amount of quaternary compounds. This material is then diluted with large volumes of water during use. 

Demineralization. Softening alone is insufficient for most high-pressure boiler feed waters and for many process streams, especially those used in the manufacture of electronics equipment. In addition to the removal of hardness, these processes require removal of all dissolved soHds, such as sodium, sihca, alkalinity, and the mineral anions (Cl , and NO ). 

Thermoplastic Elastomers. These represent a whole class of synthetic elastomers, developed siace the 1960s, that ate permanently and reversibly thermoplastic, but behave as cross-linked networks at ambient temperature. One of the first was the triblock copolymer of the polystyrene—polybutadiene—polystyrene type (SheU s Kraton) prepared by anionic polymerization with organoHthium initiator. The stmcture and morphology is shown schematically in Figure 3. The incompatibiHty of the polystyrene and polybutadiene blocks leads to a dispersion of the spherical polystyrene domains (ca 20—30 nm) in the mbbery matrix of polybutadiene. Since each polybutadiene chain is anchored at both ends to a polystyrene domain, a network results. However, at elevated temperatures where the polystyrene softens, the elastomer can be molded like any thermoplastic, yet behaves much like a vulcanized mbber on cooling (see Elastomers, synthetic-thermoplastic elastomers). 

Aikaiinity Bicarbonate (HCOs" ), carbonate (COs , and hydroxyl (OH ), expressed as CaCOs Foaming and carryover of solids with steam embrittlement of boiler steel bicarbonate and carbonate produce CO2 in steam, a source of corrosion Lime and lime-soda softening, acid treatment, hydrogen zeolite softening, demineralization, dealkalization by anion exchange, distillation, degasifying... 

Note 1 Older systems may have cation/anion deionizers in place of softeners/reverse osmosis. Note 2 Older systems may use chlorination for microbial control. 

Among the three-dimensional silicates are the zeolites, which contain cavities or tunnels in which Na+ or Caz+ ions may be trapped. Synthetic zeolites with made-to-order holes are used in home water softeners. When hard water containing Ca2+ ions flows through a zeolite column, an exchange reaction occurs. If we represent the formula of die zeolite as NaZ, where Z represents a complex, three-dimensional anion, the water-softening reaction can be represented by the equation... 

Provision of pretreatment The initial fill volume and MU supply is almost always pretreated in some manner. Because of the large volume of water in these systems, even low-hardness waters can produce sufficient quantities of calcium carbonate scale to severely impede heat transfer thus, for MTHW pretreatment, the use of ion-exchange softeners is the norm. For HTHW, some form of demineralization such as reverse osmosis (RO) or deionization by cation-anion exchange is typically preferred. 

NOTE If the BW contains phosphate, the preferred reaction is for calcium to precipitate as hydroxyapatite, rather than to chelate with EDTA or NTA (a further competing anion effect). Consequently, there would seem to be no valid reason to produce combined phosphate-chelant programs, with the chelant acting as a reserve against unforeseen hardness incursions caused by a softener leakage, or other source. In practice, the chelant acts to solubilize existing deposits, producing a very clean boiler. 

Hard, attrition-resistant, insoluble synthetic polymers (typically a copolymer of styrene with divinylbenzene). The resins are manufactured in a spherical bead shape that contain either exchangeable anion or cation portions, capable of exchanging with other anions or cations and usually in an aqueous medium. Typically cation resins for water softening will have a practical operating capacity of 20,000 gpg (at 6 lb NaCl per cu ft) rising to 30,000 gpg (at 15 lb NaCl per cu ft). 

Quaternary ammonium compounds are cationic surfactants that bind well to anionic surfaces like the protein in hair. The ammonium end sticks to the hair, leaving the long fatty end of the molecule to act as a lubricant. They are slightly conductive, so they reduce the buildup of static electricity. Quats, as they are sometimes called, include compounds like stearalkonium chloride, disteardimonium chloride, quaternium-5, or quaternium-18, polyquaternium-10 and they are all similar in form and function to cetrimonium chloride. These compounds are also widely used as fabric softeners, for all of the same reasons they make good hair conditioners. They are also used to thicken the shampoo. 

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