Cooking up Bioplastic
Updated: Dec 12, 2019
I've been ranting a lot about plastics this year. It's impossible not to want to scream after watching The New Plastics Economy by the Ellen McCarther Foundation, Ted Talks about plastic-eating bacteria, or The Plastic Problem from PBS. The material that built the 20th Century looks like it may drown the 21st. The search for solutions is on and I'm eagerly watching many of them. Bioplastics are high on the list. I've worked with biobased materials - like mushroom leather and PLA yarns, but if you asked me to make it, I would have said I'd require a Ph.D. and advanced industrial equipment... Sometimes it's great to be wrong!
Apparently, biobased plastic can be cooked up in your kitchen! Plastic just means " “having the power of molding or shaping formless or yielding material”. Ingredients can be found in your pantry (or the baking aisle of your supermarket).
Bioplastic color experiments
After a playing mad scientist and some trial and errors, I've settled on my own recipe for multi-colored bioplastic:
Hotplate or burner
Small pot (I preferred a coffee milk warming pot for ease of pouring)
Small metal whisk
Silicone cooking molds
1 cup of water
¼ cup gelatin powder
1 Tbsp glycerine (animal or vegetable)
Water-based food coloring
Coat silicone mold with a very light coating of Vasaline to guarantee no sticking.
Add drops of the food coloring into the mold.
Blend water and gelatin powder in pot before moving to burner.
Heat until a low simmer and add glycerine. Cook for 10-12 minutes stirring regularly with a whisk.
Pour the clear liquid into the molds. The color drops will spread and blend as the liquid hits them.
In 5 minutes it'll be cool to the touch and rubbery like Jello.
Within 60 minutes you can cut it cleanly (ie using a straw to punch out a spot for a hole) or use a cookie cutter.
Leave in the mold for 3-4 days to dry out. (The thicker the plastic, the longer it will take to dry.)
If you want a colored plastic, stir in food coloring with the glycerin in step 3.
For clear plastic, scoop off any foam before pouring into the molds.
If you want an opaque foamy plastic, bring it to a boil and pour the foam into the molds.
It will also curl as it dries if you remove it from the mold too soon.
This bioplastic is NOT heat or water resistant. If you put it in a microwave it will melt. If you put it in water it will dissolve.
Some additional info:
Oregon State University's wonderful project “Fork it up!” for science classes, grade 6-12, for their Bioenergy Education Initiative. It includes project details, experiment variations, history, and follow-up materials.
Materiability also offers a tutorial and a fun project video:
Lastly, I highly recommend checking out the Bioplastics Cookbook. It offers a range of experiments with different materials and additives including the vegan options to replace the gelatin.