Superabsorbent polymer, often known as SAP or superabsorbent material (SAM), finds diverse applications in both consumer and industrial sectors due to its remarkable ability to absorb water and aqueous solutions, absorbing up to 500 times its weight in liquid. Originally developed in the 1960s by the US Department of Agriculture to enhance water conservation in soil, the initial polymer was starch-based, but modern SAP technology shifted to hydrocarbon-derived polymers, specifically crosslinked acrylic polymers neutralized with sodium.

Superabsorbent polymers have become a staple in the hygiene industry, with around 3 million tons produced annually. Their applications include feminine hygiene pads, baby and adult diapers, and various incontinence products.

Chemistry of Superabsorbent Polymers: Superabsorbent polymers used in Gelok laminates and airlaids are typically formed through the reaction of acrylic acid monomer with sodium hydroxide and a cross-linking agent, resulting in polyacrylic acid sodium salt. Gel Polymerization is the most common technique, where components are sprayed onto a moving belt in the presence of UV light, causing crosslinking. Suspension Polymerization and Solution Polymerization are alternative methods.

Application of Superabsorbent Polymers: When these polymers come in contact with aqueous liquids, such as urine or blood, they absorb water through osmosis. This makes them ideal for personal hygiene and incontinence products, as they can retain large amounts of liquid even under pressure. However, when in contact with liquids containing high salt levels, absorption capacity decreases.

Important Characteristics of Superabsorbent Polymers:

• Particle size
• Free swell absorption capacity
• Absorption capacity under load
• Water retention properties
• Rate of water absorption
• Polymer permeability
• Gel strength
• Wicking capability