biofoilextraflexible.md



BIOFOIL EXTRA FLEXIBLE

Images of final product
Caption, Image credit, Year
Caption, Image credit, Year
Caption, Image credit, Year

Description
A transparent, glossy and very flexible sheet of gelatine-based bioplastic. Slightly sticky.

Physical form
Surfaces & Surface Treatments

Fabrication time
Preparation time: 1 Hour
Processing time: 5-7 days
Need attention: None, just leave it to dry as long as is feasible.
Final form achieved after: 1 week

Ingredients


Gelatine powder - 24 gr

Functions as the polymeer (so it becomes a solid)


Glycerine - 18 gr

Functions as plasticizer that bonds with the gelatine (makes it flexible). This recipe has a bit more glycerine to make the foil less rigid. It doesn't have the "crackling" sound as a result.


Water - 200 ml/gr

To dissolve and mix the polymeer and plasticizer


Tools


Cooker or stove (optional: temperature controlled)
Pot
Scale

Acrylic sheet (or silicon mat) for casting. The smooth surface results in a very shiny, transparent foil.
Spoons
Whisk (optional)


Yield before processing/drying/curing
Approx. 200 ml

Method


Preparation

Weigh your ingredients
Prepare the acrylic sheet and find a place where you can leave it for a while


Mixing and dissolving the ingredients

bring the water to the boil
optional: add natural dye if you wish to use color
add the glycerine
add the gelatine
keep the temperature below 80 degrees celcius while stirring very very slowly and gently to avoid making bubbles. I prefer a simple spoon to do this, not a whisk.


Cooking the ingredients

Simmer and slowly stir the mixture between 60-80 degrees celcius for 20 minutes. I turn it lower when I get bubbles. You don't want the liquid to move, don't boil it.
Longer cooking time allows more water to evaporate. You will get a thicker, more syruppy liquid that spreads slower: resulting in a thicker sheet.


Casting the foam

Let the liquid cool for a couple minutes until it gels a little but is still liquid, like syrup.
Cast onto the acrylic sheet slowly to avoid bubbles
Pour from the middle and hold still, let the liquid distribute itself
Let it dry for 48-72 hours at least before releasing. If it feels cold to the touch it is still drying. Patience pays off with these sheets


Drying/curing/growth process
Peel it off the mold after 48-72 hours (enjoy the sound it makes!)

Mold depth:  N/A
Shrinkage thickness:       30-50 %
Shrinkage width/length:    0-10 %

Shrinkage and deformation control
Letting it dry up to a week to get to the final form. For storage: keep it flat and cover with baking paper. It gets a bit sticky and can cling onto itself when folded for longer periods of time.
Curing agents and release agents
None.
Minimum wait time before releasing from mold
3 days (up to a week is best)
Post-processing
Store flat in a dry and ventilated room.
Further research needed on drying/curing/growth?
Yes. Casting onto textured surfaces is likely to require a different technique and/or molds that have walls to ensure even distribution.

Process
Mixing the ingredients at 80 degrees, Loes Bogers, 2020
The gelatin is dissolved: stirring very very slowly, Loes Bogers, 2020
, Releasing the sheet from the acrylic, Loes Bogers, 2020

Variations on this recipe

Add a natural colorant such as a vegetable dye or water-based ink (e.g. hibiscus, beetroot, madder)
Add less glycerine for a more rigid foil

Stiffeners such as fibres, yarn or natural debris may be added for more structure and reinforcement.

Fillers such as almond or sunflower oil, can be added to prevent additional shrinkage but might affect stickyness.


Cultural & ecological information

Where are the ingredients locally abundant?
Gelatin is collagen extracted from the skin, bones, and connective tissues of animals (e.g. cattle, chicken, pigs, fish). It can be produced almost anywhere, so try finding a local supplier. In the Netherlands, Jacob Hooy sells gelatine made from cow's skin.
Glycerin is a sugar alcohol derived from animal products, plants or petroleum. As such it can be produced almost anywhere. Try to find a vegetable-based glycerine that is produced locally. In the Netherlands, Orphi is an affordable vegetable-based glycerin brand.
Water quality is not of the essence for this recipe. Most tap water will be fine. The PH level of the water might affect PH sensitive natural colorants (e.g. ink or dye extracted from blueberries, red cabbage or other vegetables rich in anthocyanins).
Needs further research?  Not sure

Cultural origins of this recipe
Bioplastic production is older than petrol based plastics. In 1500 BC, people in Egypt were already using glues based on gelatin, casein and albumin for furniture constructions.
Needs further research?   Not sure

References this recipe draws from


Biofoil (gelatin) Recipe by Cecilia Raspanti (Textile Lab, Waag), Fabricademy Class "Biofabricating", 2019, link.

The Bioplastics Cookbook by


Known concerns and contestations*
Needs further research
Gelatin is an animal-based ingredient. Some might find it problematic to use resources that requires killing an animal because of religious or animal welfare beliefs. Arguments are also made that as long as there's a meat industry, it is better to use product from the entire animal, including skin and bones. Some might consider gelatin to be a product that comes from a waste stream, but this is considered controversial by others.
Acrylic is a petrol based plastic but results in very shiny foils and sheets and can be reused endlessly for casting high quality bioplastic sheets.

Sustainability tags

Renewable ingredients: yes
Vegan: no
Made of by-products or waste:  yes
Biocompostable final product:  yes

Needs further research?:  not sure
Gelatine-based bioplastics can be recasted by melting them in a pot with some water. Recycling them with PET plastics contaminates the waste stream. Compost bioplastics in a warm environment with sufficient airflow.

Material properties

Comparative qualities
The biofoam feels like the foam-like packaging materials sometimes used for shipping fragile goods or thick foamy kitchen cloth. It feels colder to the touch and is slightly stickier. The upside shows visible bubbles, but the mold-facing side feels very smooth if the mold had a smooth surface. It somewhat keeps the smell of the dishwashing liquid.

Technical and sensory properties


Strength: medium

Hardness: flexible

Transparency: translucent

Glossiness: satin

Weight: light

Structure: closed

Texture: smooth

Temperature: cool

Shape memory: medium

Odor: moderate

Stickiness: medium

Weather resistance: poor

Acoustic properties: needs further research

Anti-bacterial: needs further research

Non-allergenic: needs further research

Electrical properties: no

Heat resistance: low

Water resistance: low

Chemical resistance: needs further research

Scratch resistance: poor

Surface friction: sliding


Tactility & sound impression
[youtube embed here]

About this entry

Maker(s) of this sample

Name: Loes Bogers
Affiliation: Fabricademy student at Waag Textile Lab Amsterdam
Location:  Amsterdam, the Netherlands
Date: 19-02-2020 – 26-02-2020


Environmental conditions

Humidity:  75 – 85 %
Outside temp:  5-11 degrees Celcius
Room temp:  18 – 22 degrees Celcius

PH tap water:  7-8

Recipe validation
Has recipe been validated? Yes
By Cecilia Raspanti, Textile Lab, Waag Amsterdam, 9 March 2020

Estimated cost (consumables) in local currency
0,50 Euros for a yield of approx 150 ml

Local supplier/sourcing info
Gelatin powder - Jacob Hooy (online retailers)
Glycerine 1.23 - Orphi/Chempropack (online retailers)
Eco dishwasing soap - any (eco)supermarket
Lego sheet - second hand/flea market/thrift shop

Copyright information

This recipe is in the public domain (CC0)
No

This recipe was previously published by someone else
Yes
Biofoam Recipe by Cecilia Raspanti (Textile Lab, Waag Amsterdam), biofoam sample from the material archive, n.d.
##References


The Secrets of Bioplastic by Clara Davis (Fabtex, IAAC, Fab Lab Barcelona), 2017, link.

Glycerin by Materiom, n.d. link.