Sustainable Dyeing Mechanism of Polyester with Natural Dye Extracted from Watermelon and Their UV Protective Characteristics

The practice of natural colorants for polyester fabric dyeing has been rampantly rising in our consumer fashion. In this study, two separate natural colorants were extracted from watermelon (Citrullus lanatus) rind (WRS) and flesh (WFS) for polyester coloration. The optical and colorimetric properties of saps and dyed fabrics, dye fiber bonding phenomena, chromophores diffusion behaviors, color-fastness, ecological and economic aspects were examined through various analyses and the corresponding mechanisms were proposed. A wide range of chromophores diffusion was noticed for several parameter variations and the resulting diffusions were ranging from 42.67 to 83.13 %. Interestingly, WRS and WFS robust the UV shielding properties into the dyed fabric and the recorded UPF rating was found to be above 50. All color-fastness properties including sublimations were very good to excellent (4 to 4/5) except lightfastness. Finally, the ecological and economic aspects of WRS/WFS dyeing were also compared with commercial disperse dyes.