The new approaches for polymer recyclingAuthor(s): Milan Kracalik
Polymer recycling has become a critical issue of academic as well as industry discussions in the last years. One of critical issues is recycling of the car tires. There are at least 300 mil- lion tires on deposit in the United States and this amount is increasing continuously. In 1990, only 17 % of produced tires have been recycled. In the meantime it is possible to find the market for nearly 78 percent of used tires. However, the rest of used tires ends on registered or illegal deposits or land dis- posals. Furthermore, it is estimated that only less than 10% of waste rubber is reused into new product (physical recovery), i.e. the main part of collected rubber is used for thermal or chem- ical recovery. The main problem of physical recovery consists in rubber crosslinking i.e. it is not possible to process it again into new products. As the chemical devulcanization methods are very time consuming as well as expensive, there is a need to find an effective mechanical devulcanization technology in order to support physical recovery, which is industrially attrac- tive. Physical recovery approach can be also combined with nanotechnology, which is one another topic with continuously growing industrial interest.Nanocomposites made of polymers and layered silicates (clays) by melt mixing are of great interest for both industrial and environmental points of view because of increasing effort to develop new tailored materials and also to recycle the growing volume of polymers especially in pack- aging field. In this work, two examples of efficient polymer recycling us- ing physical recovery for thermosetting as well as thermoplastic materials are presented: new approach for mechanical devul- canizationof care tires and for increasing the processability of PET waste.