How does polymer absorb water

It absorbs water by a process called osmosis. When the sodium-containing polymer is placed in contact with water, there is a tendency for the sodium to distribute equally between the network and the water.

That means, some of the sodium atoms want to leave the network and move to the water. When these sodium atoms leave, they are replaced with water molecules.

Water swells the polymer network to try to keep the sodium concentration balanced between the polymer and the water. Sodium polyacrylate can absorb times its weight in distilled water, but only times its weight in tap water, since tap water contains some sodium, calcium and other mineral salts. The experiment below will illustrate this phenomenon. Using a 4 oz. How many times its own weight in water did the polymer absorb?

The amount of cross-linking, called the crosslink density, determines the properties of the super absorber. Widely used in agriculture, forestry, and gardening, such as soil water retention agent , seed coating , soil-less cultivation , artificial turf , etc.

Industrial grade SAP can be mainly used in sandbags , protection materials of concrete , waterproof tape, and waterproof ointment for use in optical fiber cables and so on. Please prove you are human by selecting the Tree. Skip to content What is a super absorbent polymer? How does it work? Construction workers, bicyclists and motorcyclists may be seen wearing cloth headbands or wearing a cloth collar around their neck.

The crystals are sewn into a pouch in the cloth. The cloth item is then soaked in water for several hours. A tiny handful will swell up to many times it size and provide moist evaporative cooling for the wearer. Florists also use polymer crystals as a dirt-free way to store water and to keep cut flowers fresh for a long time. It takes about 45 minutes to hydrate the typical headband or collar. Refrigeration ahead of time is not necessary, but it does help extend the cooling time.

The same polymer crystals can be rehydrated many times. The following picture shows how the same crystals appear several hours later after about an ounce of water was poured on the crystals:. Sign up for our Newsletter!