Bioplastics: Screening & Forming
Oxford Brookes School of Architecture · BA Year 3
COMPOSITE WALL
A structural and insulating wall component made from layering two forms of bioplastic and steel reinforcements. Creating an innovative, lightweight and low cost enclosure for use in the Pocket Dyers design project. Incorporating benefits found in traditional rainscreen cladding systems and the use of waste/renewable bioplastic materials.
RAINSCREEN
Folding a gelatine based bioplastic screen and pinning it to a rigid starch based bioplastic wall, creating a translucent rainscreen cladding with a ventilated and drained cavity.
weatherproof
air gap
INSULATION
A starch based bioplastic formed through moulding into lightweight insulated walls and combined with steel reinforcement. With reduced thickness the bioplastic is translucent.
Material Samples
01. starch (02), vinegar (02), glycerol (01), water (14) no colouring air-dried (10 days) | 02. starch (16), vinegar (02), glycerol (01), water (14) blue colouring air-dried (10 days) |
| 03. starch (02), vinegar (02), glycerol (01), water (14) no colouring air-dried (03 days) | 04. starch (02), vinegar (02), glycerol (01), water (14) no colouring microwave (03 mins) |
| 05. starch (04), vinegar (02), glycerol (01), water (14) blue colouring air-dried (03 days) | 06. starch (04), vinegar (02), glycerol (01), water (14) blue colouring microwave (03 mins) |
| 07. starch (08), vinegar (02), glycerol (01), water (14) blue colouring air-dried (03 days) | 08. starch (08), vinegar (02), glycerol (01), water (14) blue colouring microwave (03 mins) |
| 09. starch (16), vinegar (02), glycerol (01), water (14) blue colouring air-dried (03 days) | 10. starch (16), vinegar (02), glycerol (01), water (14) blue colouring microwave (03 mins) |
| 11. starch (08), vinegar (02), water (14) blue colouring air-dried (03 days) | 12. starch (08), vinegar (02), water (14) blue colouring microwave (03 mins) |
| 13. starch (12), vinegar (02), water (14) blue colouring microwave (03 mins) | 14. starch (12), vinegar (02), water (14) blue colouring microwave (05 mins) |
| 15. starch (04), vinegar (02), glycerol (01), water (14) blue colouring air-dried (03 days + hair-dryer) | 16. starch (04), vinegar (02), glycerol (01), water (14) no colouring oven (01 hours) |
| 17. starch (12), vinegar (02), water (14) blue colouring microwave (03 mins) / weathered (water) | 18. starch (12), vinegar (02), water (14) blue colouring microwave (03 mins) / weathered (frozen) |
| 19. starch (12), vinegar (02), water (14) green colouring microwave (03 mins) | 20. starch (12), vinegar (02), water (14) green colouring microwave (04 mins) |
| 21. starch (12), vinegar (02), water (14) green colouring microwave (04 mins) | 22. starch (12), vinegar (02), water (14) green colouring microwave (04 mins) / sanded |
| 23. starch (16), vinegar (02), glycerol (01), water (14) blue colouring air-dried (10 days) | 24. starch (16), vinegar (02), glycerol (01), water (14) blue colouring air-dried (10 days) |
| 25. gelatine (04), glycerol (01), water (20) no colouring air-dried (14 days) | 26. gelatine (04), glycerol (01), water (20) blue colouring air-dried (14 days) |
| 27. gelatine (04), glycerol (01), water (20) no colouring air-dried (14 days) | 28. gelatine (04), glycerol (01), water (20) no colouring air-dried (14 days) / weathered (water) |
| 29. gelatine (04), glycerol (01), water (20) no colouring air-dried (14 days) / weathered (frozen) | 30. starch (12), vinegar (02), water (14) blue colouring microwave (15 mins) |
| 31. starch (12), vinegar (02), water (14) blue colouring microwave (15 mins) | 32. starch (12), vinegar (02), water (14) blue colouring microwave (20 mins) |
| 33. starch (12), vinegar (02), water (14) no colouring tension test | 34. starch (12), vinegar (02), water (14) no colouring compression test |
| 35. starch (12), vinegar (02), water (14) no colouring compression test |
Bioplastics are plastics from renewable biomass sources, such as vegetable fats, corn starch or animal products. Traditional plastics are primarily derived from petroleum and produce more greenhouse gas.
Bio-Polymer(s) + Bio-Plasticizer(s) + Other Additive(s) = Bio-Plastic
The starch/gelatine is the polymer. Polymers are large chains of molecules like plastics, the acidic vinegar + heat breaks down polymers which then reform when drying. Glycerin makes the plastic more flexible and soft.
MAKING
GELATINE · SCREENING
Combine the gelatine, glycerin, water and colouring then heat gently until frothing. Remove from the heat and continue to stir. Pour into a flat mould and leave to air dry. Can be shaped while semi-dry.
STARCH · FORMING
Combine starch, vinegar and colouring ensuring no lumps. Heat and stir as it rapidly turns from liquid to gelatinous paste. Low starch ratios are less viscous. Briefly wait for it to cool before pushing into a mould and microwaving. Check frequently to avoid overheating.
FAILURES
Microwave overheating starts to burn the inside of the plastic and the centre can explode outwards. Oven heating/drying is hard to control and results in partially dry samples, while air drying starch tends to crack.
TESTING
STRUCTURAL
Load testing starch based moulded wall samples.
COMPRESSION
TENSION
plasterboard
bioplastic
THERMAL
A basic thermal conduction comparison using a FLIR thermal camera between plasterboard and starch based bioplastic. The air cells of the starch bioplastic caused a transfer reduction of 7°C.
TUTORS Johan Hybschmann, Matthew Springett, Maria Kessler & Margaret Bursa
2014-15
© Theo Jones · Creative Commons