Synthetic polymers can be divided into thermoplastics and thermosets. Thermoplastics are referred to as plas-tics. Plastics consist of large polymeric molecules, see Figure 9.1. At room temperatures, the individual mole-cules are condensed to a solid phase due to intermolecu-lar cohesion forces. By increasing the temperature be-yond a critical value – which lies in the range of 180–260° C for most plastic types – plastics will melt. This property makes them suitable for recycling into new plastic prod-ucts. Examples of major plastic types are polyethylene (PE) and polypropylene (PP), polystyrene (PS), polyethyl-ene terephthalate (PET) and polyvinyl chloride (PVC).