Make your own bioplastic

Plastic has gotten a pretty bad reputation, especially due to the pollution of the oceans, and new approaches are now being sought on how to avoid plastic or replace it with other materials. A very promising approach is the so-called bioplastic, which has properties like plastic, but is made from biological materials and is also biodegradable again. In this experiment I will show you a process for the production of bioplastics.

	This experiment requires hot milk! Young scientist should do this experiment together with their parents and leave the hot liquid part to them.
	The chemicals used in this experiment might stain your clothes.

Materials you need for this experiment:

500 ml milk	This is the basis for your bioplastic
sieve	Helps you to get rid of the water
2 tablespoons vinegar	Converts the milk to bioplastic (under the proper conditions)
paper towel	Is needed to clean up and to reduce the amount of water in your bioplastic even further
cooking pot	For making the milk warm

How to make the bioplastic:

	Since it is easier in some places when there are two of you, you should only do this experiment with your parents. Put half a liter of milk in a pot and warm the milk. It is important that it only gets warm and never boils (your mother can show you how to set the stove so that the milk only gets warm). In my case I heated the milk to around 60°C, although the temperature doesn't really matter as long as the milk doesn't boil.
	Then add two tablespoons of vinegar.
	Stir so that the milk and vinegar are well mixed. White flakes are now formed - the so-called casein - which we can separate from the remaining liquid with the sieve.
	Have your parents help you with this because it is easier if someone holds the sieve and the second person carefully empties the liquid into the sieve (remember that the liquid is still hot and be careful!).
	This white casein is our bioplastic, which we now place on a few sheets of paper towel and also press on it from above with a few sheets of paper towel. This will get the water out (if necessary, repeat this step a few times until the excess water is drained) and we can model this mass like playdough and make whatever we want out of it.
	However, once we have it in the shape we want, we still have to let it dry and set for two more days. Then you have your self-made bioplastic. You get around 100g of bioplastic from half a liter of milk.

The industrial process for producing bioplastics is a bit more complex, but for our purposes this simple process is enough. If this basic version worked, you can experiment, for example how you can color it or what happens if you mix various other materials (baking soda,...) into the casein? You can not only make bioplastics from this material, but also glue. Do you manage to find out which material you have to add when to turn it into an adhesive? Have fun experimenting!