A bionanocomposite based on cellulose nanofibers modified by a sustainable heterocyclic dispersing agent with outstanding mechanical properties

A novel bionanocomposite (BNC) based on polybutylene succinate (PBS) is developed, utilizing sustainably sourced cellulose nanofibers (CNFs) modified by a functionally designed heterocyclic polymeric dispersing agent (H_P) based on sustainable isosorbides. The enhanced hydrogen bonding interactions between H_P and CNFs lead to the effective exfoliation of aggregated CNFs, their uniform distribution within the PBS matrix, and strengthened interfacial interactions between PBS and H_P-modified CNFs. These interactions result in a marked improvement in the mechanical properties of BNC. As a result, the BNC film, with a thickness of 110 µm, demonstrates superior mechanical properties, including an 18.6 % increase in tensile strength, a 33.3 % increase in elongation at break, and a remarkable 77.1 % increase in toughness, compared to neat PBS. These outstanding properties are attributed to the robust interactions between CNFs and H_P, the well-distributed H_P-modified CNFs within the matrix, significantly enhanced interfacial adhesion between the matrix and H_P-modified CNFs, and an increased degree of crystallization in the matrix. A mechanism underlying the improved dispersibility and enhanced mechanical properties is also proposed in this study, employing molecular simulation and FT-IR spectroscopy using model systems.