Superabsorbents are a key component of hygiene products like baby diapers or adult incontinence products, ensuring that urine is locked up and kept safely away from the skin, keeping the skin and clothes dry and clean.
Today’s disposable diapers are real high-tech products, which have become even more comfortable, thinner and absorbent over the past years. An important reason behind this development has been innovative superabsorbents like HySorb® and SAVIVA® by BASF.
How superabsorbents work and how they improve our lives
Superabsorbents are humble in appearance: In the shape of an inconspicuous white powder they are mostly hidden in the core of diapers, adult incontinence and hygiene products and therefore generally out of sight. But their effect is impressive. Superabsorbents have the ability to absorb and retain large quantities of liquid even under pressure. Superabsorbents are instrumental in ensuring that diapers do not overflow and that the skin remains dry and healthy.
A superabsorbent experiment - How superabsorbents work
One gram of superabsorbent can absorb up to 500 grams of pure water. As we move from the properties of one single particle to those of a small amount of powder, superabsorbents can easily solidify large volumes of water. Through the use of less powder in the same amount of water, the water, instead of solidifying, is transformed from a free flowing fluid into a thick gel. Depending on the amount of superabsorbent used, the required viscosity can easily be adapted.
Superabsorber is made by combining (polymerizing) single molecules of sodium acrylate* and acrylic acid* to form lang molecular chains. The polymerization is activated by an initiator* and a crosslinker* connects the single molecules together to form a polymer network.
The crosslinker ensures that the granules remain insoluble when exposed to moisture, maintaining their absorbent properties and structure.
In the dry polymer granules the functional salt groups along the crosslinked chains are tightly packed together.
Upon contact with aqueous liquid the sodium ions become dissociated generating an osmotic pressure which drives more liquid into the Superabsorber binding it tightly within.
Superabsorbents are the reason why modern diapers are so small, light and comfortable. Before, in the mid-1980s, superabsorbent polymers started being used for diapers, much more material was needed. Baby diapers were thicker; with just under 100 grams they weighed around three times as much as they do these days and could retain significantly less urine. Under pressure, a large part of the liquid was squeezed out. Nowadays, around 13 grams of superabsorbents are sufficient to prevent a diaper from running out and protect the skin from moisture for hours.
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BASF Global Hygiene Portfolio
These days, it is difficult to imagine the world of modern hygiene without superabsorbents. Whether for baby diapers, incontinence or feminine hygiene products, none of them would be complete without the white polymer granules that ensure that the fluid is safely locked away and that skin and clothes remain dry and clean.