Upcycling Plastic?
The NewScientist reports a process in which polyethylene plastic bags can be “upcycled” into nanotubes.
Pol made the nanotubes by cooking 1-gram pieces of HDPE or LDPE at 700 °C for 2 hours in the presence of a cobalt acetate catalyst and then letting the mixture cool gradually. Above 600 °C the chemical bonds within the plastic completely break down and multiwalled carbon nanotubes grow on the surface of the catalytic particles.
A lot of catalyst is needed to get good results – about a fifth of the weight of the plastic being converted – and it cannot easily be recovered afterwards. But Pol says this is still one of the cheapest and environmentally friendly ways yet found to grow nanotubes.
OK. Hear me out. HDPE plastic melts at around 250 °C (depending upon how pure it is; HDPE melts at a higher temperature than LDPE). Knowing that, how is it that you can cook it at 700 °C without having it burn?