The key lies partly in the very broad selection of available polymer types, but it is above all the special ingredients that producers and compounders use to achieve exactly the right characteristics. Additives help to adjust the polymer properties to users’ needs, whether soft and flexible, rigid and flameproof, extremely tough and strong, coloured or bacteria-repellent. And producers guard their recipes very closely. The variations may be tiny, but they make all the difference in terms of marketing and use.
The huge variety of polymers in the market poses great challenges for recyclers processing waste plastics into materials that are fit for use in high-quality applications. This can be done more easily when single grades of plastics like PET bottles are processed. However, upcycling becomes diffcult – if not impossible – when the waste consists of similar plastics with only slight differences, so that the only solution is to downcycle them. One alternative is thermal recycling of waste, generating energy and heat.
