Development of superhydrophobic jute for food grain storage applications

Abstract

Jute is one of the most abundant, biodegradable, inexpensive, and renewable natural fibers. It is primarily used to store grains. Jute exhibits superior mechanical strength, but its affinity for water remains a significant weakness. The moisture absorption in extremely humid environment shortens the shelf life of the grains stored in the jute bags or degrades their quality. To address this issue, the present work relates to developing superhydrophobic jute inspired by nature, such as the lotus leaf. A surface must have synergetic roughness and low surface energy for exhibiting superhydrophobicity. In present work, the coating was prepared in two stages. The jute was initially treated with an alkaline solution. The alkali-treated surface was then sprayed with a silane coating solution to create a superhydrophobic jute. In addition, efforts were made to make the coating accessible without further heat treatment. The modified jute had a water contact angle (WCA) of approximately ∼163 ± 5⁰. In addition, the prepared surface possesses outstanding characteristics such as coating durability and high water repellency. Despite these properties, the coated jute retained the same tensile strength as the original one. The water absorption ability of uncoated and coated jute was calculated at about 3 % and 500 %, respectively. For 45 days grain storage experiment, the coated jute bag containing wheat grain's moisture content was evaluated at 12.7 %, whereas 20.3 % for the uncoated jute bag. For the grain's safety, the leached OTS amount was evaluated about 0.4 mg/dm², which is less than the permissible limit (10 mg/dm²). Therefore, the coated jute has proven to be an effective solution for reducing airborne moisture in grains.