Synthesis and Characterization of Carboxymethyl Cellulose‐Based Food Packaging Hydrogel Film From Invasive Weed Senna didymobotrya Using Citric Acid as a Crosslinker and PEG as a Plasticizer

Abstract

ABSTRACT Food waste is a global problem, especially in developed countries. Therefore, this research synthesized a hydrogel film from carboxymethyl cellulose (CMC) derived from the invasive weed Senna didymobotrya for use in food packaging. The CMC was mixed with citric acid as a crosslinker and PEG as a plasticizer to prepare the hydrogel film. The hydrogel film with a higher tensile strength of 14 kPa was prepared by mixing 2 g of 80% PEG and 20% citric acid into the initial 2 g of the CMC‐PEG mixture. The degree of swelling of the hydrogel film with the highest tensile strength (14 kPa) was 416%. This indicates that the hydrogel film can effectively absorb moisture. This hydrogel film can also retain moisture for 24 to 48 h. Similarly, the TGA analysis of this hydrogel film showed that it was thermally stable up to 202°C. All this indicates that the prepared hydrogel film can be used to pack food with good moisture‐absorption capacity and thermal stability. Additionally, this research demonstrated that weeds can be converted into valuable materials, such as CMC and hydrogel film.