Gelatine bioplastics
Gelatine is made from collagen present in animal parts and comes in jelly, sheet or powder. It is a spiral waste product from the meat industry, being repurposed for uses outside of that industry.
General protocol:
Tools and extra's
Pot, scale, spoon, whisk, stove
embroidery hoop, textiles, meshes, moulds or other casting surfaces (surface transfers texture to your bioplastic)
Pigments, powders, paints or natural dyes
Fillers of your choice (egg shell powder, coffee debris, chalk, fibers, ...)
Ingredients
(This is the general protocol, see the recipies section below for the exact amounts per material)
Gelatine (polymer)
Glycerine (plasticizer)
Water or dyed water (solvent)
Essential oil (anti-bacterial)
How to
Mix the gelatine with the cold water in your pot, and stir until dissolved. Warm up the mixture on your stove to a max of 80C.
Add your plasticizer and two drops of essential oil. The general rule is: the more glycerine, the more flexible the material, but do not exceed 1:1.
Simmer for 15 minutes while stirring regularly, then let the liquid cool for a couple minutes while stirring, until it gels a little but is still liquid. The mixture should be at least honey-like before casting. Remove any froth with a spoon, or absorb it using a coffee filter or kitchen paper (cartouche). TIP: Longer cooking time (up to an hour) allows more water to evaporate and will dramatically reduce shrinkage of your casted object. You will get a thicker liquid. To cast larger volumes and solids with this recipe, evaporate a lot of water, until it's very very thick. Sometimes it's worth reheating and melting scraps, they've already dissipated a lot of water and result in nice castings.
Optional: Add a filler and mix gently until it is evenly distributed throughout the liquid.
Slowly, and while keeping the flow in one place to avoid air bubbles, pour the mixture in your mould or on your chosen surface. Note: Don't cast hot bioplastic on acryllic that is thinner than 7mm, it will bend.
Drying / curing
Let the material dry in a ventilated and dry room and de-mould when your plastic feels solid, but still cold to the touch - often after 24-48 hours. Keep ventilated and regularly turn your piece over until it is dry, so as to avoid mold formation with long drying times.
Material properties
Water resistance: Gelatine bioplastics start dissolving after a couple of hours when submerged in room temperature water. It instantly melts when submerged in water of > 60C.
Heat resistance: Gelatine bioplastics aren't heat resistant and will start melting between 30-50C. When microwaved, the material dissolves quite quickly.
Gelatine bioplastic recipes:
#1 Gelatine bioplastic (basic recipe)
Gelatine 48 gr
Glycerine 12 gr
Water 240 ml
Two drops of essential oil
This is the basic mix from which you can start playing around with more or less glycerine. It is also a great recipe for composites (e.g. with textiles) and mixtures with powders or other dry elements. This recipe yields appr. 250 ml of material to be cast (depending on the amount of water that you let dissipate during the cooking process).
#2 BIO-RESIN
Gelatine 48 gr
Glycerine 8 gr
Water 240 ml
Two drops of essential oil
Mix all the components at medium heat (60C) until smooth, then simmer at max 86C for 10-15 mins, or more for less shrinkage, but be sure the liquid remains 'pourable' . It is also possible to boil the liquid at 100C for 5-10 mins. The process of boiling will change the chains and make the cast material significantly harder, almost epoxy-like, but slightly more brittle.This recipe yields appr. 200 ml of material to be cast (depending on the amount of water that you let dissipate during the cooking process).
#3 BIO-SILICONE
Gelatine 48 gr
Glycerine 24 gr
Water 240 ml
Two drops of essential oil
This is the starting recipe for silicone mixtures, from here you can add even more glycerine, until 1:1 ratio, where you will only add a splash of water and slowly mix by heating. This recipe yields appr. 250 ml of material to be cast (depending on the amount of water that you let dissipate during the cooking process).
#4 BIO-FOAM
Gelatine 45 gr
Glycerine 30 gr
Water 60 ml/gr
Dishwashing soap (organic) or green soap 1 teaspoon (+/- 6 ml)
Two drops of essential oil
This recipe will result in a soft, fairly flexible, foamy biomaterial. To create more or less flexibility, vary the amount of glycerine between 5 gr (brittle) and 60 gr (very flexible). Use a hand whisk or electric whisk to fiercely whip the air into the mixture before casting. Try out other frothing tools such as an electric milk foamer or even a regular straw to help you create and trap different-size air bubbles within the mixture. !! While whipping the mixture, the added air will make it solidify quickly. Be sure to keep your pan on medium heat to keep the mixture soft. Reheat if needed to melt it down again.
#5 BIO-FOIL EXTRA FLEXIBLE
Gelatine powder 24 gr
Glycerine 18 gr
Water 200 ml
Two drops of essential oil
A transparent, glossy and very flexible sheet of gelatine-based bioplastic. Slightly sticky. This foil is thick and strong and completely transparent, a bit like the PVC table cloths some people may have on their kitchen table to protect the woord from staining. In the picture, roughly ground madder root was added to the mixture before casting.
sources:
BioFabricating Materials - Textile Academy 2020-2021 24 recipes to start a local sample archive - Loes Bogers Bioplastic Cook Book - Anastasia Pistofidou
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