Introduction: Uncontrolled release of agrochemical products, as well as climate change, has damaged agricultural soils, requiring the development of sustainable materials for their regeneration. Simultaneously, the eutrophication of runoff channels and seas has promoted the overgrowth of macroalgae, which serves as a base material for the production of biopolymers. In this context, this study develops sodium alginate–glycerol-based bioplastic through injection molding techniques, evaluating its potential application for improving soil quality.
Methods: Physicochemical properties were determined using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and colorimetry tests. Mechanical performance was evaluated using strain and frequency sweep tests, as well as temperature ramps. Moreover, water uptake capacity and soluble matter loss were measured. Finally, biodegradability tests were developed to evaluate the modification of soils before and after the incorporation of the matrices.
Results: Alginate-based bioplastics exhibit favorable mechanical properties when injected at a high mold temperature (100 °C) rather than 60 °C, due to their transparent, amorphous, and stable structural material, resulting from a thermosetting procedure. Additionally, blends exhibit favorable interactions, as observed in XRD, as well as enhanced thermal stability. Their biodegradation time was below 180 days, and their behavior in calcareous soil was characterized by a pH rise and a reduction in electrical conductivity and organic matter content.
Conclusions: Sodium alginate-based bioplastics show potential for soil regeneration due to their modification of soil properties, highlighting their contribution to sustainable agricultural techniques.
Acknowledgments: This research is part of the applied research and innovation project "Desarrollo de matrices proteicas para la liberación controlada de nutrientes y agua en horticultura" (SOL2024-31712) cofunded by UE – Ministerio de Hacienda y Función Pública – Fondos Europeos – Junta de Andalucía – Consejería de Universidad, Investigación e Innovación.
