SolutionsClothing and Textiles
1. Natural or synthetic?
Classify these fibres and say what kind of polymer they are: cotton, silk, nylon, polyester (PET).
- Cotton: natural; cellulose (polysaccharide).
- Silk: natural; protein (polyamide).
- Nylon: synthetic; polyamide.
- Polyester (PET): synthetic; polyester.
2. Cotton or polyester
Why does a cotton T-shirt absorb sweat much better than a polyester one?
The cellulose of cotton has a great many OH groups that form hydrogen bonds with water. Polyester has hardly any groups able to form them and is much less polar, so it absorbs very little water (although it dries faster).
3. Water-repellent fabrics
Why do water drops not wet a fabric coated with a fluorinated polymer?
Because the fluorinated surface is very non-polar and hardly attracts water molecules: water prefers to bind to itself through hydrogen bonds and forms almost spherical drops that roll off.