LDPE wears the ‘number 4’ badge, and is a thermoplastic made from monomer ethylene. It is tough, but will break with the right amount of effort. It is very commonly used due to it’s highyl unreactive nature. It is difficult and expensive to recycle. In parts of the world, it is being banned, as it is one of the most common pieces of litter and there are more environmentally friendly alternatives.
Uses of LDPE Plastic
- Grocery bags
- Refuse bags
How is LDPE Recycled?
As LDPE is heated, it turns from a solid, to a viscous gummy liquid and then to a mobile ﬂuid as temperature is increased. The melting point of LDPE is just 115°c. Because of LDPE’s nature of having such a low density and melting point, it allows for a process called ‘ﬂoat-and-sink’ to be used to separate it from the other polymer chemicals. Separation is performed in a ﬂotation tank using water to execute the separation.