biofoam.md



BIOFOAM

Tactility & sound impression


Description
A thin, textured sheet, and half domes of foamy, flexible bioplastic. Gelatine-based.

Physical form
Surfaces, Solids

Fabrication time
Preparation time: 1 Hour
Processing time: 5 days
Need attention: after 3 days to demold, and keep pressed. After another 2 days to take them out of the press and air dry/store.
Final form achieved after: 1 week

Ingredients


Gelatine powder - 12 gr

Functions as the polymeer (makes it hard)


Glycerine - 12 gr

Functions as plasticizer that bonds with the gelatine (makes it flexible)


Water - 150 ml/gr

To dissolve and mix the polymeer and plasticizer


Dishwashing soap (organic) - 1 tsp

Is the expanding agent that makes the mixture foamy


Tools


Cooker or stove (optional: temperature controlled)
Pot
Scale
Spoons
Whisk

Lego sheet (or other textured surface)

Egg holders (or other mold), these came with my fridge


Yield before processing/drying/curing
Approx. 150 ml

Method


Preparation

Weigh your ingredients
Prepare the molds you wish to use


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 gently, until the gelatine is dissolved


Cooking the ingredients, creating foam

Simmer and slowly stir the mixture between 60-80 degrees celcius for 20 minutes or until it's thick like a syrup or honey, then add in the soap
Whisk vigorously to create foam bubbles and simmer for another 2-5 minutes until the mixture thickens
Stir slowly to let the bigger bubbles pop until you have a foam with small bubbles


Casting the foam

Cast onto the lego sheet (or other textured sheet) and spread out if necessary. Cast in the center of the sheet and allow the material to spread itself, keeping the pot still for even results. Or cast into the cups.
The material will shrink a lot so make the layer thicker than you want the end result to be.
Let it dry for 48-72 hours at least before releasing


Drying/curing/growth process
Peel it off the mold after 48-72 hours. The foam should not feel cold to the touch, then it's still drying. Pinch off the more fragile sides first to create some grip. Then pull it off carefully, pulling upwards.

Mold depth:  3 mm
Shrinkage thickness:       30-50 %
Shrinkage width/length:    0-10 %

Shrinkage and deformation control
This recipe results in a somewhat flexible material so it's ok to cast onto a rigid mold, the flexibility will allow you to release it.
The lego texture keeps the foam in place and will help reduce shrinkage on width and length.
Waiting too long to release from the mold can result in tearing. The foam gets a bit more brittle and thin as it dries. Releasing it too early might leave finger prints and presses in the foam as its still too soft.
Curing agents and release agents
None.
Minimum wait time before releasing from mold
2 days
Post-processing
The sides will curl upwards upon further drying. I cut off the thinner edges (they curl more) to create an even sheet.
You can keep the sheet pressed at intervals of a day or so between kitchen paper and a stack of books to keep it flat if it curls up. Try to air it out too to prevent mold growth.
Store flat in a dry and ventilated room.
Further research needed on drying/curing/growth?
Yes. Casting solids or smooth surface might require a different process to prevent deformation.

Process
Mixing the ingredients at 80 degrees, Loes Bogers, 2020
The gelatin is dissolved and thick, ready for the soap to go in, Loes Bogers, 2020
Whisking the liquid vigourously to create small bubbles, Loes Bogers, 2020
Releasing the foam from the half-dome molds, Loes Bogers, 2020
The lego mold with the sheet after trimming and drying: hardly any shrinkage (width/length), Loes Bogers, 2020
Pressing the sheet underneath some books to keep it flat, 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 rigid foam, add more for a flexible foam (up to 1 part glycerine, 1 part gelatine and a dash of water)

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

Fillers such as almond or sunflower oil, chalk or egg shells can be added to prevent additional shrinkage.


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. Gelatin casting as a technique has also been used in production of jelly-based foods such as aspic, jelly desserts and candy.
Needs further research?   Not sure

References this recipe draws from


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

Biofoam Recipe by Cecilia Raspanti (Textile Lab, Waag), biofoam sample from the material archive, n.d.

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


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 as to not waste anything. Some might consider gelatin to be a product that comes from a waste stream, but this is considered controversial by others.
Using renewable ingredients is not by definition petrol-free. Imagine they have to travel long distances by plane, boat or truck: it takes fuel. Also, the effects of GMO technologies and pesticides can be harmful to the environment and it's worth using knowing the source and production standards involved. If you can afford it, buying organic ingredients is a good starting point.

Sustainability tags

Renewable ingredients: yes
Vegan: no
Made of by-products or waste:  no
Biocompostable final product:  yes
Re-use: melt with heat and a splash of water, and recast

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.
Needs further research?:  not sure

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 and smells less like wet dog than other gelatin-based bioplastics.
The foam half domes are more rigid when completely dried, but still allow for some squeezing and feel foamy.

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 in final product, high during production

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

Color modifiers: none


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:  not sure
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
No
##References


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

The Bioplastics Cookbook by Fab Textiles Lab, YYYY, link


Biofoam Recipe by Cecilia Raspanti (Textile Lab, Waag Amsterdam), biofoam sample from the material archive, n.d.

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


Images of final product
Biofoam (gelatin-based), Loes Bogers, 2020
Biofoam (gelatin-based), Loes Bogers, 2020
Biofoam (gelatin-based), Loes Bogers, 2020
Biofoam (gelatin-based), Loes Bogers, 2020