A simple activity to help students understand how absorbent polymers are used in nappies.
See also The Design of Nappies
PRACTICAL: Nappy dissection
AIM: To investigate the nature of absorbent nappies.
Theory: Manufacturers place a water absorbing polymer into the cotton padding of nappies.
METHOD AND RESULTS:
- Wear safety googles and avoid contact with eyes.
- Open a sheet of newspaper on a table top
- Cut away the nappy lining to reveal the padding
- Carefully rub sections of the padding onto the newspaper. This will cause the polymer crystals to fall onto the newspaper.
(Note: The crystals look like salt.)
- Discard any cotton and carefully pour the polymer into 50 mL of water.
- Stir the mixture
- Discard the cotton padding and nappy lining into the newspaper, then into the bin. Do not place materials into the sink.
Safety: The small polymer crystals can absorbs many times their own weight in water. Avoid contact with the eyes and do not ingest.
- Add a small amount of salt to the mixture
- Describe the properties of the polymer used in absorbent nappies.
- Why do manufactures place excess absorbent polymer in nappies?
Hint: Urine contains salt.
- How do manufactures make super absorbent nappies?