recipe Science Questions
Hello! This is a good introductory question about the basics of bioplastics: what do each of the ingredients that people use actually do?
Bioplastics, like all plastic, must have at least 1 polymer and 1 plasticizer.
In the example you gave, gelatin is the polymer. It contains long carbon molecule chains that give the plastic its strength.
Glycerine is the plasticizer. It is the small molecule that gets between the polymer to make it bendy and flexible. The more plasticizer you use, the softer and more flexible the plastic will be.
The vinegar helps the two of them to get together. The fact that it contains ions helps to “disorder” the polymer chains. We actually have an article all about what vinegar does, and what you can use as a substitute if you want, here: http://green-plastics.net/posts/69/qaa-why-water-and-vinegar/
For a good basic article about why all plastics are made of a polymer and a plasticizer, check out the article on plastics on our other website: http://greenplastics.com/wiki/Plastics
I hope this helps!