The Earth’s population is growing exponentially, and so are the synthetic pollutants. Recycling plastic waste into valuable materials is one of the important challenges tp hel protect the environment. Among six major categories of plastics (as per the US Environmental Protection Agency), polyethylene terephthalate (PET) is one of the most commonly used plastic. It is used for the manufacture of water/soft drink bottles, food containers, fibers, etc. Every year around 50 million tons of polyethylene terephthalate (PET) bottles are used worldwide and only a part of this amount is being recycled. Therefore, a technology that can convert PET-based waste materials into useful ones is highly needed. In the present work, attempts have been made to convert PET-based waste materials into a precursor for others. In literature, various chemical methods for PET depolymerization have been reported. This includes aminolysis, hydrolysis, methanolysis, glycolysis, etc. Among these, aminolysis is particularly interesting due to the high reactivity (nucleophilicity) of amine leading to a faster reaction with PET. Several examples of aminolysis reactions using a diamine or amino-alcohol have been reported with or without using a catalyst.
Here they report an aminolysed product obtained by aminolysis reaction of PET with 1,2 diaminopropane (DAP, 2) under solvent and catalytic free conditions. All reactions were conducted under open air conditions. The highest amount of monomeric product was obtained upon heating the mixture of diamine and PET at 130◦C. The resulting aminolysed product was then converted to a Schiff-base with 25% yield. The chemical structure of the synthesized compounds was confirmed using multi-spectroscopic techniques (IR, NMR).
The results of this study will be a valuable addition to the growing body of work on plastic recycling leading to environment protection. Since this reaction was conducted without any solvent and at a moderate temperature, it may help to significantly broaden the scope of possible applications of PET waste. In addition, it also opens the door for the development of new compounds starting from waste materials.
Reference/ Original Article Details-
Publisher URL: https://www.mdpi.com/2073-4360/14/9/1861
DOI: 10.3390/polym14091861
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