Plastic Waste

Polypropylene Waste

Fall 2024

ARCH 5500: Processing the Anthropocene

In collaboration with JunkLabz

Course goals from Fall 2024

WASTE

Understand material waste streams once an item is thrown away
Understand how and where trash moves, where it goes and who it impacts most
Understand recycling, downcycling, and upcycling principals
Visit waste management facilities and meet with waste management professionals
Understand principles of circular economies

PLASTICS

Understand the impact of plastics from the global level down to the scale of the body, microplastics and nanoplastics
Understand the history of how and why plastics became so embedded into society
Understand the realities of plastic recycling relative to our increasing dependence on it as a material
Understand the different types of plastic, their recycling rates and potentials, as well as their performance qualities

FABRICATION

Get hands-on experience with plastic recycling processes - shredding, sheet pressing, etc
Explore a range of techniques for manipulating recycled plastic as a design material
Design and build a chair, seat, stool, or object at 1:1 scale

The Process

We work with #5 Polypropylene Plastic sourced locally from the UVA labs in the form of Pipette Boxes. Polypropylene plastic is technically recyclable, but according to a Greenpeace study titled Circular Claims Fall Flat Again from 2022, "US domestic reprocessing capacity for post-consumer PP#5 plastic waste is approximately 2-5%... When it is accepted by a MRF, PP#5 is typically collected as part of a mixed plastics #3-7 bale. There is negligible demand for these bales across the country, and the collected mixed plastics are often disposed of in landfills or destroyed by incineration." In reality, very little #5PP plastic is actually recycled.

To recycle this material, the source material is first shredded into flakes using an industrial shredder, then is weighed and mixed into different colorways. The plastic is then heated it up under pressure within an aluminum mold until it reaches a liquid state. Once all of the flakes have melted through, the mold is released from the heat press and once cool, the plastic sheet is demolded and ready to go.

Each sheet is 35" x 35" x 1/2" and requires 7.5kg (16.5 lbs) of plastic. Inevitably there is some material overflow, which we save a re-shred for future sheets.