Fabrication of eco-friendly time indicator using cellulose-based materials

Abstract

An eco-friendly time indicator (TI) was developed using cellulose-based materials. The TI comprises a dye, copy paper, nanofibrillated cellulose (NFC) film, and filter papers coated with NFC slurry and/or paraffin-free biowax. A suitable dye and its conditions were determined by observing the dye solutions and the migration pattern at the different concentrations. Commercial filter papers were prepared, and the dye migration rate, depending on physical properties, was evaluated. NFC was coated to control the dye migration rate of filter paper. In addition, biowax was used to impart hydrophobicity to filter papers used for supporting NFC films, storing the dye, and allowing the migration of dye. Finally, a TI was fabricated using those components. Methylene blue was selected as a dye for the TI due to its deep color and high solubility. The results showed that the key property of filter paper affecting the dye migration rate was the pore size. The migration rate could be reduced when NFC was coated on both sides of the filter paper. Since biowax modified the hydrophobicity of filter paper surface, it was used to make the NFC film-supporting paper, location for dye storage, and bottom-layer. In conclusion, a multilayered TI could be assembled using cellulose-based materials.

Hydrophobic and mechanical strength enhancement of hemp fabric and paper enabled by waterborne polyurethane-derived functional coating

“…Cellulose has the advantages of wide source, renewable, biodegradable, low cost, easy physical or chemical modi cation, and is considered to be the main raw material in the future energy and chemical industry (Dacrory et al 2020;Gong et al 2021;Viron et al 2021;Guo et al 2021). Applications ranging from paper, textile, hydrogel and lm to food and industrial have been investigated in cellulose-based materials (Obele et al 2021;Jo et al 2022; Kang et al 2021;Xiao et al 2018). However, the lack of special function greatly limited their further application.…”