Diapers, hydrogels

Applications of hydrogels include highly absorbent diapers based on poly(sodium acrylate), contact lenses based on poly(2-hydroxyethyl methacrylate) (polyHEMA), and switches based on variations of swelling of the hydrogels. A number of drug delivery systems have also been based on hydrogels. 

The first application developed for smart hydrogels was somewhat mundane. They were used as a liner for golf shoes and in-line skates that takes the shape of the wearer s foot as the result of heat released by the foot, but researchers have envisioned a much broader and more significant number and variety of applications for such materials. Proposed applications include optical shutters actuators and sensors for chemical, heat, and electrical systems valves chemical memory systems fluid switches absorbents for chemical and petroleum spills diapers cosmetics and desalination systems. Thus far, however, the greatest interest has been in biomedical applications of hydrogels. 

Oligomeric agents were prepared by condensing trimethylolpropane with ethylene and/or propylene oxides and capping with acrylic acid. These materials were subsequently crosslinked using 2,2 -azobisamidinopropane dihydrochloride, which formed superabsorbent swellable hydrogel addition polymers and were useful as components in diapers or in feminine hygiene products. 

In this section, we want to present some recent results which have been obtained by B. Mann using ESPResSo, and explain, how this has been done [41,43,47]. The system under investigation is a polyelectrolyte network, i.e. a gel of cross-linked charged pol uners. One of the most prominent features of such a network is that it is able to absorb large amounts of the solvent, up to several hundred times its dry mass. Due to its remarkable properties, this hydrogel has many industrial applications, e.g. as superabsorbants in diapers,... 

A copolymer of this monomer with N,N melhylenebis (acrylamide) imbibed 100 times its weight of water. This swelling was not affected by sodium chloride in the water. Most super-slurpers swell less in the presence of dissolved salts. Thus, the new copolymer may be of use in collecting urine in diapers. Another polymeric hydrogel was made by polymerization of sucrose-l -acrylate using sucrose-6,1 -diacrylate (prepared by enzymatic transesterification of sucrose and vinyl acrylate) as the cross-linking agent.155... 

Chemical or irradiation cross-linking of poly(ethylene oxide) resins yield hydrogeb, which are not water soluble but water absorptive, capable of absorbing 25-100 times their own weight of water. These hydrogels are reportedly useful in the manufacture of absorptive pads for catamenial devices and disposable diapers. 

PLA and its copolymers have several end-use applications. The major applications include short shelf-life products such as plastic bags for carrying household waste, overwrap and lamination films, barriers for sanitary products and diapers, planting, disposable cups and plates, and so on [120]. Hydrolytic degradability of PLA has generated a lot of interest for biomedical applications such as drug delivery systems [134-142], protein encapsulation and delivery [143-145], development of microspheres [146-154], hydrogels [155], bone screws [156], sutures [157-161], scaffolds [162], and so on. However, the unreinforced PLA has certain limitations and that is why a lot of researches have been dedicated to... 

Polyelectrolytes are used to modify the interaction (i.e., to increase electrostatic repulsion) between particles when absorbed on a surface. They are used in hair conditioners to coat hairs and reduce static (conditioners also contain silicones to provide a smooth coating on the hair surface). Polyelectrolytes also modify the viscosity of aqueous solutions and are extensively used as emulsifiers and thickeners. Polyelectrolyte gels based on polyacrylates are used as super-absorbent gels (termed hydrogels) in baby nappies (diapers, US). The materials are able to swell up to many... 

A polymer gel can absorb solvent up to several thousands times its original weight, depending on the chemical structure of the gel. Diapers, feminine napkins, and perfumes, used in everyday life are typical examples of this highly water-absorbing property of hydrogels. 

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