Recipe for Agar Bioplastics

GENERAL INFORMATION

Agar (also called agar-agar) is a polymer of agarose (a kind of sugar). It is a substance obtained from red algae. Agar has been used as a gelling and thickening agent in desserts throughout Asia and also in microbiology to obtain a solid medium. Agar can also be used as a vegan substitute for gelatin (made from animals). Agar bioplastic is made by mixing water, glycerine and agar powder. Together they form a foil-like plastic substitute that is flexible, but not elastic.

RECIPE
INGREDIENTS FOR 500 mL OF BASIC AGAR BIOPLASTIC FOIL

  • Agar agar 10g
    • the polymer to make the structure
  • Glycerine 30g
    • The plasticizer to make it flexible
  • Water 500 mL
    • The solvent to dissolve the materials
  • Essential oil 2 drops
    • Anti-bacterial to keep it from contaminating

 

TOOLS

  • Pan (non-reactive)
  • Cooking plate
  • Scale with 1g precision
  • Thermometer
  • Spoon
  • Whisk
  • Optional: Textiles, molds or casting surfaces
  • Optional: Pigments, food colorants or natural dyes
  • Optional: Fillers of your choice (eggshell powder, coffee debris, chalk, fibers, …)

 

METHOD

  • Warm up the water in the pan on the cooking plate to a max of 80ºC (hot, but not boiling).
    • Optional: If you want to dye your material in one colour, supplement part of the water with natural dye (if concentrated only a few drops).
  • Add the glycerin and a few drops of essential oil to the water.
    • The general rule is the more glycerine, the more flexible the material.
    • Too much glycerine will make the material too sticky.
  • Add the agar to the mixture.
    • Add slowly and evenly, while stirring gently will help it dissolve better.
  • Whisk gently until the ingredients form a smooth mix.
    • Don’t over-whisk it to avoid the creation of bubbles.
  • Simmer for about 30 minutes while stirring regularly.
    • The mixture should be syrupy rather than watery before casting.
  • Optional #1: Add a filler and mix gently until it is evenly distributed throughout the liquid.
  • Optional #2: If you are planning to make a batch of different colours, prepare your colours in a small container, to which you will add the liquid when it is ready to cast.
  • Pour the mixture into your mold or on your chosen surface.
    • Pour slowly to avoid air bubbles
  • Let dry for about a week.
    • the temperature and humidity will influence the drying time and shrinking

 

REFERENCES

  • Fabricademy by Loes Bogers, 2020, Link
  • Agar Bioplastics Lab Pastoe by Shirley Niemans, 2021, Link
  • Agar on Wikipedia: link
  • Margarita Talep Algae Bioplastic Packaging Design by Natashah Hitti for Dezeen, 2019: link