PRODUCT PROFILE Superabsorbent polymers (SAP) (also called slush powder) are polymers that can absorb and retain extremely large amounts of a liquid relative to their own mass. Water absorbing polymers, which are classified as Hydrogels when cross-linked, absorb aqueous solutions through hydrogen bonding with water molecules. A SAP's ability to absorb water is a factor of the ionic concentration of the aqueous solution. In deionized and distilled water, a SAP may absorb 500 times its weight (from 30-60 times its own volume), but when put into a 0.9% saline solution, the absorbency drops to maybe 50 times its weight. The presence of valence cations in the solution will impede the polymers ability to bond with the water molecule. Super absorbent polymers (SAPs) are compounds that absorb water and swell into many times their original size and weight. They are lightly cross-linked networks of hydrophilic polymer chains. The network can swell in water and hold a large amount of water while maintaining the physical dimension structure. Process for SAP: The processing of Super absorbent polymers is done by neutralization in which super absorbent polymer is lightly cross linked with Polyacrylic acid. There are two main raw materials for manufacturing of SAP, viz. acrylic acid and cross linkers like glycerine or other polyhydric alcohols. To obtain good quality of SAP, high purity of acrylic acid is desired. Acrylic SAP manufacturing is usually a four, and in some cases, a three step process. The polymer is made by aqueous solution polymerization of glacial acrylic acid with cross linking monomer and an initiator. Acrylamide is used as well as co monomer for some industrial applications. Neutralization is carried out pre or post polymerisation depending on the type of reactor and reaction conditions. The polymer is a soft, rubbery gel that is colourless and clear. The soft gel intermediate is placed on a belt and run through a long tunnel that blows hot air for drying. A drum dryer is also used to a lesser extent. The dried hard cake is ground to granular amorphous powder. Finally, the tiny particles undergo further cross linking mostly at the surface to reduce extractable polymers and residual monomer. Another round of heating causes a reaction that yields the final cross linked product. Almost 92.3% of world capacity is based on aqueous solution polymerization. About 7% of capacity is based on inverse suspension polymerization that results in micro beads. APPLICATIONS • Superabsorbent polymers can be blended with polymer adhesives and coated on non woven fabrics to make waterproof belts. • It can also be processed into coatings with butyl rubber and solvents and then coated on polyester belts. • SAPs are widely used in personal hygiene products. Recent research is focused in other application areas of SAPs, viz., bio sensing, soft actuators/valves, catalysis, concentration of viruses, vitamin, bovine serum albumin and controlled drug delivery. • SAP features moisture absorption, has no toxicity and no corrosion and can therefore be used in the storage and packaging of foods, fruits and vegetables. • SAP can be blended with polymer adhesives and coated on non woven fabrics to make waterproof belts. • It can also be processed into coatings with butyl rubber and solvents and then coated on polyester belts. Global Scenario Demand for SAP has been rising steadily during the last few decades. Global demand growth is forecast at 6% per annum through 2016. This is a result of rising demand for disposable diapers, primarily in countries with rising disposable incomes and low current penetration rate of SAP. Although smaller market in comparison to diapers, strong growth is forecast to continue in feminine hygiene products and in incontinence products in developed regions, as a result of efforts to produce slimmer, more efficient products. The application of SAP, in optical cables in particular, is expanding and the market prospect is excellent