Water hyacinth-derived biodegradable mulch films reinforced by a gelatin/oxidized carboxymethyl cellulose network with improved mechanical and barrier properties

Developing biodegradable mulch films from renewable biomass is important for sustainable agriculture. In this study, a biodegradable mulch-film system was constructed using hemicellulose derived from water hyacinth, Eichhornia crassipes (Mart.) Solms, as the dominant matrix. Gelatin/oxidized carboxymethyl cellulose (GOC) was introduced as a crosslinked reinforcing phase, and lignosulfonate was used as a functional additive. β-Cyclodextrin-encapsulated abamectin was further incorporated as a model active component to evaluate the protective capacity of the film system. The results showed that Schiff base crosslinking between gelatin and oxidized carboxymethyl cellulose enhanced film stability. This crosslinked structure also enabled coordinated regulation of the thermal, mechanical, water-related, and barrier properties of the films. Among the tested formulations, HC-GOC35-Lig exhibited the best overall performance. It showed a tensile strength of 16.08 MPa, an elongation at break of 37.17%, and a water contact angle of 102.39°, together with reduced water-vapor permeability and improved ultraviolet- and oxygen-barrier properties. The optimized film also showed favorable mulch-related agricultural performance, including enhanced soil moisture retention, thermal buffering, seed germination, and seedling growth. In addition, it provided effective protection for β-cyclodextrin-encapsulated abamectin under light exposure. Soil-burial observations indicated visible post-use disintegration under the tested soil-burial conditions. A preliminary pest-related assay showed that the film-forming solution allowed larval feeding, whereas β-CD-ABA incorporation was followed by larval mortality under the tested conditions. Overall, this work provides a feasible strategy for valorizing water hyacinth biomass into high-value biodegradable mulch films and expands the application potential of hemicellulose-based agricultural materials.