All diapers including adult diapers and baby and toddler diapers do have sodium polyacrylate that is used to absorb the urine.
Some diapers such as cheaper adult diapers may container smaller amounts of sodium polyacrylate and or some pulp from wood.
The crystalline substance that is found in disposable diapers is sodium polyacrylate which is used to absorb the urine or pee that goes into the diaper.
As the sodium polyacrylate absorbs the pee the gel swells up and causes the diaper to swell up as well.
A disposable diaper works by use of gel particles that are made of plastics that also contain synthetic polymers that consist of long chains of smaller molecules.
Attached to the chains are sodium ions which is the gels secret to luring water molecules or urine inside their structure at a reasonably low temperature.
When pee enters makes contact with the polymers the polymers inside the disposable diaper work to absorb the pee and they swell up.
This is the reason you notice the diaper swells up as it gets wet with pee which means the gel in the diapers are doing their job at locking in and aborbing the pee to keep the child's skin dry.
Whether it is made for a baby or an astronaut, the major disposable diaper brands all contain a powdery chemical absorbent called sodium polyacrylate, which can absorb over 300 times its weight in water!
Sodium polyacrylate is an absorbent polymer that is used as an emulsion stabilizer, a hair fixative, a film former, skin conditioner, and a viscosity agent.
You will see them as the gel like crystals in baby diapers, which are makes them absorbent.
Sodium polyacrylate is an example of a super-absorbing polymer.
It is a cross-linked (network) polymer that contains sodium atoms.
It absorbs water by a process called osmosis.
Sodium polyacrylate is not toxic.
In the process of synthesizing sodium polyacrylate, the content of acrylic acid can be strictly controlled and is not harmful to the human body.
In fact, sodium polyacrylate has been widely used as an important water-absorbing component of baby diapers.
Due to their production and disposal, these are very environmentally hazardous.
Disposable diapers contain a lot of plastic, synthetic materials, paper, different chemicals, all mixed with feces and urine.
And tons of used diapers end up in landfills and rivers.