Absorbent polymers
Thermoplastics > Superpolymers > SAP
| Superabsorbent Polymers SAP | |
| The superabsorbent polymers (in English Super Absotbent Polymers or SAP), are polymers that can absorb and retain extremely large amounts of liquid relative to its own mass. The water absorbent polymers, which are classified as hydrogels when reticle absorb aqueous solutions through hydrogen bridge bonds with water molecules. The ability of an SAP to absorb water is a factor of the ionic concentration of the aqueous solution. Ionized water and distilled des, an SAP can absorb 500 times its weight (30 to 60 times its own volume) and can be up to 99.9% of liquid, but when placed in a saline 0.9% , low absorption capacity to perhaps 50 times its weight. The presence of cations in the solution prevents the ability of the polymer to bond with the water molecule. The total absorbency and swellability are controlled by the type and degree of crosslinking agents used to make the gel. SAP low crosslinking density generally have a greater absorbent capacity and swell to a greater degree. These types of SAP also have a softer gel formation and sticky. Polymers with high crosslink densities exhibit lower absorbent capacity and swell, but the gel strength is firmer and can maintain the shape of the particles, even under moderate pressure. The increased use of SAP is in disposable personal hygiene products such as baby diapers, adult protective underwear and sanitary napkins. |  |
| Sodium polyacrylate | |
As mentioned, one of the super absorbent polymers most used is sodium polyacrylate. It is a polymer formed from monomers -CH2CH (CO2Na) -. It is a white, odorless powder. You can increase your volume up to a thousand times if you add distilled water. Because of its qualities is used in diapers, sanitary towels or chemical processes requiring water absorption. The ability to absorb large amounts of water because there sodium carboxylate groups hanging main chain of the compound composition in its molecular structure. These groups, when in contact with water emit sodium, leaving free negative ions carboxyl. Negative ions are repelled, stretching the main chain and causing increased volume. For the compound again be stable and neutral. | |
| Copolymers | |
The superabsorbent polymers are made today from the polymerization of acrylic acid mixed with sodium hydroxide in the presence of an initiator to form a salt of polyacrylic acid (sodium polyacrylate). This polymer is the most common type of SAP made in the world today. | |
| Applications | |
Different superabsorbent polymers can be used for a variety of applications, among which are: the controlled release of insecticides and herbicides, diapers and incontinence garments, filtration, as thickeners and sequester, intumescent, carrier fragrances, Frog tape or tape toad (tape tech designed for use with latex paint), toys (growing in water), packs or packs heat therapy and cold, solidification of medical waste, water beds motionless, spill control, surgical pads, potting soil, waste stabilization and repair the environment, water retention to supply water to plants, water blocking cable, wound dressings, removal of water from aviation fuel,removing moisture in packaging, artificial snow among many other uses. |