| الوصف: |
Plastic waste constitutes one of the most important sources of pollution worldwide. Despite the growing recycling trend, nowadays there are no effective technologies that can compensate for the continuous increase in plastic production. Polyesters and polyamides are one of the most produced single-use plastics, mainly used in manufacturing textiles and soft drinks bottles. Today, only a very low fraction of these polymers can be recycled. It can be done by exploiting two leading technologies: mechanical and chemical recycling. Mechanical recycling represents, nowadays, the most used industrial application. However, it can treat a very narrow range of waste materials due to the impossibility of removing dyes and the deterioration of mechanical properties due to the incompatibility of different plastic materials. Another critical limit of this recycling technology is the limited number of recycling loops that can be done due to the thermal degradation that occurs during the extrusion process. The second possibility is chemical recycling, which allows the depolymerization of the original product to recover the monomers directly. The main drawbacks are the long reaction times and the many solvents needed to achieve high-purity products. Therefore, chemical recycling is economically feasible, only for big companies that can produce the virgin polymer in situ. In this work, a new technology has been patented. This process is constituted of three main steps. The first one is the distillation-assisted cyclodepolymerization (DA-CDP), introduced as a modification of the CDP process. In this unit, cyclic oligomers together with high molecular weight compounds have been produced. Then, after polymer purification, it is possible to achieve the same molecular weight of the initial polymer in less than 30 minutes, exploiting the ring-opening polymerization (ROP) in the next step. |
