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 (HP) based on sustainable isosorbides. The enhanced hydrogen bonding interactions between HP and CNFs lead to the effective exfoliation of aggregated CNFs, their uniform distribution within the PBS matrix, and strengthened interfacial interactions between PBS and HP-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 HP, the well-distributed HP-modified CNFs within the matrix, significantly enhanced interfacial adhesion between the matrix and HP-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.