Applying Microwave-Assisted Carbon Quantum Dots for Enhancing the Properties of PET

Carbon Quantum Dots (CQDs) have garnered significant interest in recent years due to their unique properties, including high UV-blocking capabilities and low toxicity. This makes them a promising candidate for the use in packaging applications. For packaging applications, the incorporation of CQDs into non-aqueous polymers such as polypropylene (PP) and polyethylene terephthalate (PET) are being explored. We have synthesized CQDs using citric acid in acetone, and then incorporated into PET using a spray coating method with various concentrations in the range of 0~0.7%. The PET/CQDs composite films were prepared using a hot-press process. The synthesized CQDs was analyzed using UV-visible spectroscopy, PL and TEM. The prepared PET/CQDs composite films was evaluated using FTIR, DSC, UVVis, OTR measurements to understand their chemical, thermal, and UV-blocking properties. It was observed that the UVblocking properties of the PET film containing 0.7% CQDs were significantly enhanced, with a 50% reduction over pure PET. Furthermore, the PET/CQDs composite film with 0.1% CQDs showed the lowest OTR value of 20 g/m2·day, comparing to pure PET of 41 g/m2·day for. These results demonstrate how PET/CQDs composite films can be used in packaging, particularly in sectors where improved UV-blocking qualities are crucial.