Bio-based Terpolymers: Synthesis, Characterization, Wet-Spinning, and Evaluation as Geotextile

Microplastics (MPs) are a priority environmental pollution issue worldwide due to their poor biodegradability and persistent contamination. Nowadays, there is a growing interest in the design of biopolymers as an alternative for the total or partial substitution of plastic materials that generate MPs. In this paper, new biodegradable terpolymers (BPAN) with starch (ST), chitosan (CS), acrylonitrile (AN), 2-hydroxy ethyl methacrylate (HEMA), and vinyl acetate (VA) have been synthesized with different chemical properties using suspension polymerization initiated by sodium bisulfite/ammonium persulfate. The effect of polymerization conditions, concentration, and types of monomers on the characteristics of BPAN was analyzed. Cultured fungal and Burial test were used to test the biodegradability of a selected BPAN. Biodegradable fiber (BioF) from a BPAN was obtained by wet-spinning and used for the fabrication of geotextiles. The effective use of the geotextiles, on radish plant growth and soil moisture retention, was examined. The results showed that the polymerization system AN-HEMA-ST base provides good polymer conversion rate, high molecular weight, high moisture retention, and high grafting efficiency. The biodegradation of a film from a selected BPAN was observed by changes in coloration and fragmentation of small particles after 150 days of Burial test. Functional group changes from FTIR analysis confirmed the degradation. Fungal growth after 13 days of observation on sprayed BPAN also confirmed biodegradability. In addition, biocompatibility was observed by root growth on the surface of the BPAN film. With the AN-HEMA-ST based BPAN, a fiber with a linear density of 10.7 denier, tensile strength of 2.88 MPa, 10.71% elongation, and 88% moisture retention could be obtained. The use of geotextile from BioF increased soil moisture retention by about 100%. Biometric analysis of radish plants showed that in pots with geotextile, there was an increase of 62.12% in leaf length, 39.78% in leaf width, and 81.73% in leaf stem thickness, concerning the control experiments. The technical orientation for the synthesis, processing, and application of bio-based materials are the basis for the generation of new and better alternatives for sustainable engineering, environmental care, and regeneration of soils affected by PMs.