Water-treatment polymers

Synthetic water treatment polymers were first introduced in the 1950s. The first important synthetic polymers included hydrolyzed polyacrylamide and various high molecular weight (100,000+) homopolymers of polyacrylic acid and polymethacrylic acid, together with their sodium salts. 

Each water treatment service company has the same potential access to research and development information from the manufacturers of water treatment polymers, biocides, and other starting-point materials. This... 

There is a mean annual increase in world demand of about 3%, driven mainly by ABS/SAN resin and other applications. Acrylonitrile is also used to produce adiponitrile (for manufacture of hexamethylenediamine used in Nylon-6,6 fibers and resins) and acrylamide for water-treatment polymers. Approximately 52% of the total EU production of acrylonitrile is used in production of fibres, 15% in production of ABS and SAN resins, 15% in the production of acrylamide and adiponitrile, and 18% for other uses [2]. 

Polystyrene is an important commercial polymer. Its success in the industry is attributed to its unique chemical and physical properties and to its competitive pricing. Because of its uniqueness in chemical properties, polystyrene can be chemically functionalized or physically modified to obtain usefiil properties. As a result, modified polystyrene finds broad utility in packaging, home constmction, transportation, water treatments, polymer supported reagents, and polymeric catalysts. Because of its very low cost, product developers continue to have good incentives to use polystyrene as the prime material for product development. As new needs develop, more and more modification techniques will be developed to meet the new challenges in material science. 

New Saccharide-Derived Monomers and Their Use in Water-Treatment Polymers... 

Saccharides have a number of attributes that make them very attractive as raw materials for the synthesis of polymers. The confluence in saccharides of different functionalities such as multiple hydroxyl groups and latent reactivity, which is difficult to realize in wholly synthetic materials, is of particular interest to us. The preparation of monomers derived from saccharides and the subsequent polymerization of these materials is one approach that has been extensively pursued as a means to introduce saccharide groups into synthetic polymers (1-9). With a few exceptions (2), most of this previously reported work has involved attaching a polymerizable moiety onto a mono- or disaccharide. The practical synthesis of a new family of monomers derived from carbohydrates ranging from monosaccharides to large oligosaccharides and the use of these monomers to produce a detectable water treatment polymer are described in this paper. 

Labeled Water Treatment Polymer. Low molecular weight poly(acrylic acid) is used as a dispersant for mineral scale in water treatment applications. The water treatment polymer is added to the aqueous system in a predetermined concentration that is effective to inhibit the formation and deposition of mineral scale. The concentration of the polymer must be monitored over time in order that the amount of polymer present in the system can be maintained at the predetermined concentration. 

Low molecular weight poly(acrylic acid) is difficult if not impossible to detect directly in aqueous solution at the concentrations at which it is employed in water treatment applications. There are, however, many classic colorimetric techniques for the quantitative detection of saccharides down to the ppm level (75). If a poly(acrylic acid) water treatment polymer is prepared with pendent saccharide functionality, detecting the polymer reduces to a problem of detecting the saccharide functionality. With monomers of the type 5 in hand, we were able to explore this strategy for the preparation of a detectable water treatment polymer. 

The effectiveness (and efficiency) of two saccharide labeled water treatment polymers as calcium scale inhibitors were then evaluated against low molecular weight poly(acrylic acid), which served as a control. The results of this study are summarized in Table I. The scale inhibition of the labeled polymers was comparable to that of the control at 5 ppm. This indicates that the saccharide tag has no adverse effect on the water treatment performance of the polymer other than, perhaps, to dilute the amount of acrylic acid residues present per unit of polymer present (note the drop in the performance of the experimental polymers relative to that of the control polymer at a concentration of 3 ppm). 

A very practical and broadly applicable two-step synthesis of a new family of monofunctional saccharide monomers was developed (16). In this synthesis, all reactions are done in water, no protecting groups are employed, and no by-products are formed. These saccharide-derived monomers were found to be useful as tags for water treatment polymers (7 7). 

Chen F, Bair KA. Water treatment polymers and methods of use thereof. US patent 4659480. 1987. 

Additionally, some general guidelines apply to the feeding and handhng of all water treatment polymers. In areas where the temperature routinely drops below freezing, it is good practice to insulate all polymer feed lines. 

W.L. Chou, D.G. Yu, M.C. Yang, The preparation and characterization of silver-loading cellulose acetate hollow fiber membrane for water treatment, Polym Advan Technol, 16 (2005) 600-607. 

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