Eco-friendly composite materials of polybutylene succinate with clay minerals, lignin and canabrava fiber

Abstract

The widespread use of plastics in seedling production, due to their convenience and cost-effectiveness, poses significant environmental challenges, including pollution and high resource consumption. To address these issues, a sustainable hybrid bio-composite was developed using bio-polybutylene succinate (PBS) combined with canabrava fibers (Cana) (up to 30 wt%), lignin (Lig), montmorillonite (MMT), and sepiolite (SEP). This bio-composite, featuring a negative carbon footprint and fully biodegradable components, offers a promising alternative to polypropylene packaging in seedling production, enhancing environmental sustainability and promoting the valorization of waste materials like Cana and Lig. The bio-composites were synthesized via melt blending in an extruder, and their mechanical, thermal, and morphological properties were evaluated. The melt flow rate could be effectively managed by adjusting the combination of Cana, Lig, and clays, achieving values comparable to polypropylene (EP440L). Notable enhancements in mechanical properties were observed relative to neat PBS, with increases in Young's modulus (up to 353 %), yield stress (up to 198 %), flexural modulus (up to 390 %), and flexural strength (up to 160 %). These improvements are mainly attributed to the high Cana fiber content and the hybrid effects of clays, particularly SEP. However, reductions in impact resistance and elongation were noted compared to neat PBS and EP440L, likely due to limited fiber-polymer interactions and increased compactness as observed in SEM analysis. FT-IR analysis indicated strong interactions between clays and PBS, evidenced by a shoulder at 1602–1608 cm⁻¹. XRD analysis suggested the exfoliation of MMT, as indicated by the absence of the (001) plane reflection, although the high content of Cana may have mitigated some mechanical benefits. DSC analysis revealed increased crystallinity with the incorporation of Cana, Lig, and clays, likely driven by nucleation effects. The presence of SEP was associated with a secondary melting peak, indicating effective dispersion and interfacial crystal formation. Enhanced thermal stability was demonstrated by a higher temperature at 90 % mass loss compared to neat PBS. These findings suggest the bio-composite is a sustainable alternative for reducing plastic waste in seedling production.