We have been in discussion and exchanging ideas with a charity called ReBOOT – Moray Computer recycling. Andrew Drummond came all the way from Moray to visit the Plastic Lab with a bag of shredded plastic. He accidentally helped us trying to fix our extrusion machine and we tested the polymer he brought.
The extrusion machine did not survive (will come back to it later on) but we have tested ABS recycling for the first time (that’s what many computer cases are made of).
ABS stands for Acrylonitrile butadiene styrene and has its glass transition around a hundred degrees Celsius. In factory it is injected at 200+︒C degrees. Because styrenes tend to release quite some gas, we decided to try the lowest temperature possible by increasing the heat steps by steps . Around 180 ︒C you can start deforming it. We only get 8 tonnes pressure available so we heated to 195︒C that the resin was more fluid. This was only based on experience and the aspect of the plastic and should be more seriously investigated for further developments.
We pressed with the base of the mold hot (at temperature) and the top was at room temperature (so called cold). This resulted in 2 very different textures after pressing: a sleek base slightly fractured with a beautiful pattern and a rough upper surface also beautiful. The resin didn’t quite fill the mold because probably it was not fully at the same temperature through the whole mass. Consequently it didn’t flow well laterally.
When we passed 175︒C the ABS started degassing a lot. We have a large extraction with carbon filtersg but still we needed the masks to be comfortable. The recycled product is beautiful but as many forms of plastics, an atmosphere-controlled environment is better than a workshop. It is unlikely that we will recycle such plastic in the future but we learned a lot an did a new object from trash. Hopefully ReBOOT will have access to bigger facilities and do something with the large volumes of electronic casing discarded.