A COMPARATIVE STUDY OF CASSAVA PULP AND COMMERCIAL-GRADE CDS/LDPE COMPOSITE FILMS WITH APPLICATIONS IN PLANTS

Carbon dots (CDs) synthesized from cassava pulp using a green hydrothermal method have gained attention for several applications. CDs in composite films were used for UV blocking due to their outstanding optical properties, which include high UV absorbance and photoluminescence. In this study, low-density polyethylene (LDPE) was mixed with 2 wt% CDs to form composite films via a solvent-casting technique. Physical, chemical, and optical characteristics were examined using a Zetasizer, FTIR spectrometer, UV-vis spectrophotometer, and UV transilluminator to compare cassava pulp carbon dots (CDs) with commercial-grade carbon dots (CDs-c). Subsequently, the optical properties of 2% CDs/LDPE composite films were compared with 2% CDs-c/LDPE composite films. UV blocking of the films was tested by measuring chlorophyll content and plant growth. The results suggested that CDs had optical characteristics comparable to CDs-c. The 2% CDs/LDPE composite films exhibit nearly identical UV absorbance to the 2% CDs-c/LDPE composite films. Yellow fluorescence of the two composite films is caused by the sensitivity of the carbon core structure along with the hydroxyl and carboxyl groups on the surfaces of CDs. Applications of composite films showed that plants protected from UVC by CDs/LDPE films had high chlorophyll content due to high UVC absorbance and greater light transmission. However, plants protected by CDs-c/LDPE film with low light transmission did not show affected chlorophyll. Although 2% CDs and CDs-c/LDPE films have high UVC absorbance, their UV-C blocking was limited.