Super-absorber

Functional derivatives of polyethylene, particularly poly(vinyl alcohol) and poly(acryLic acid) and derivatives, have received attention because of their water-solubility and disposal iato the aqueous environment. Poly(vinyl alcohol) is used ia a wide variety of appHcations, including textiles, paper, plastic films, etc, and poly(acryLic acid) is widely used ia detergents as a builder, a super-absorbent for diapers and feminine hygiene products, for water treatment, ia thickeners, as pigment dispersant, etc (see Vinyl polymers, vinyl alcohol polymers). 

Obana et alP reported a modified ethyl acetate extraction which used a super absorbent polymer instead of sodium sulfate to absorb water. Eollowing cleanup by carbon-based SPE and/or gel permeation chromatography (GPC), recoveries in excess of 70% were achieved for the majority of the 107 pesticides of interest in asparagus, orange, potato and strawberry. The super absorbent polymers are now being incorporated into ASE procedures. 

Dextrose, obtained from starch, is the raw material for sorbitol and other sugar alcohols and polyols. Isolated starch (usually from corn) can be chemical modified and is used in large amounts as an inexpensive binder in the textile and paper industry. Chemically modified starch can be used as super-absorbers or in polymer manufacturing. 

Main application of the poly(acrylic acid) super-absorbents is in disposable, sanitary and hygienic systems, for example, diapers. 

The class of hydrophilic and water-absorbent polymers are superabsorbent polymers (SAP). Super absorbent polymers are polymers that can absorb and retain extremely large amounts of a liquid relative to its own mass. 

Super absorbent polymers. These cross-linked acrylic polymers are used in baby diapers. Copolymer versions are used in agriculture and other specialty absorbent applications. 

These cross-linked acrylic polymers are referred to as Super Absorbents and Water Crystals . The origins of super absorbent polymer chemistry trace back to the early 1960s when the US Department of Agriculture developed the first super absorbent polymer material. This chemical is featured in the Maximum Absorbency Garment used by NASA. 

Super absorbent chemistry requires two things The addition of small cross-linking molecules between the polymer strands and the partial neutralization of the carboxyl acid groups (-COOH) along the polymer backbone (-COO Na+). 

A view of a crosslinks in super absorbent molecules is shown in Fig. 2.21 and the more practical polymer network in Fig. 2.22. 

An interesting possible application in our society is in super absorbers, which are currently made with polyacrylates, but these suffer from poor biodegradability. Since the demand for short-use super absorbers is growing, a product with a short lifetime and therefore a quick and safe disposal is required. Carboxylated starch can be such a product, but first, an efficient method to oxidize starch needs to be developed. Currently used methods produce stoichiometric amounts of waste products, so the search for a catalytic process is ongoing. 

Acrolein and Acrylic Acid from Propylene for Super-Absorbent Polymers, Paints, and Fibres... 

A super-absorbent material manufactured by radiation grafting techniques has come onto the market recently. The material is capable of absorbing and holding large amounts of liquid. Products manufactured from it include disposable diapers, tampons, and air-freshener elements. 

Super Absorbent Magic Water Gel Hydrolyzed starch/acrylonitrile copolymer... 

The Japan Industry Standards (JIS). Testing Method for Water Absorption Capacity of Super Absorbent Polymers, K7223, 1996. 

Masuda, F. Properties of superabsorbent polymers. In Super absorbent Polymers Kyoritsu Shuppan Tokyo, 1988 51-80 (written in Japanese). 

PPG is an improved super absorbent polymer (SAP). SAPs are a unique group of materials that can absorb over a hundred times their weight in liquids, and they do not easily release the absorbed fluids under pressure. Super absorbent polymers are used primarily as an absorbent for water and aqueous... 

Health and Nutrition (pharmaceuticals, dental products, feed additives and super absorbants) ... 

Zhang Y-Q, Tanaka T, Shibayama M. Super-absorbency and phase transition of gels in physiological salt solutions. Nature 1992 360 142-144. 

Biotechnology research is seeking to develop new foods, feeds, fiber, and biomass energy production processes that are environmentally safe. Researchers are developing new uses for agricultural products to replace non-renewable sources of raw materials. Their work promises to have broad commercial applications and has already led to the creation of new industries. These discoveries have led to environmentally compatible commercial products such as biodegradable plastics (60), soybean oil printing inks, and super absorbent polymers (67). 

Many other high volume consumer products make use of one or more core layers with absorbent properties. Among the most quickly and highly developed applications are baby diapers, which use super absorbent fibers. Super absorbent polymer (SAP) molecules can trap and hold hundreds to thousands of times their own weight in fluid, ultimately forming a gel. The super absorbent core layer in a diaper is between a non-woven cover stock, a one or two layer non-woven fluff/pulp sheet that takes up, distributes, and draws liquid into the core, and a microporous back sheet. In addition, elastomeric materials and waterproof elements are incorporated. The super absorbent core not only stores liquid but actively pulls moisture out of the damp or even wet fluff/ pulp, thus leaving the contact areas soft and dry. 

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