Enhancement of seaweed‐based biofilms with cellulose nanofiber: A comparative study on raw seaweed and semi‐refined carrageenan for sustainable packaging applications

Abstract Seaweed has garnered global attention for its applications in sustainable materials, owing to its renewable and biodegradable nature. This study investigated the incorporation of cellulose nanofiber (CNF) into raw seaweed (RS) and semi‐refined carrageenan (SRC) biofilms to evaluate its impact on their structural, thermal, and mechanical properties. CNF, characterized by a high aspect ratio and zeta potential (−38.9 mV), demonstrated enhanced interfacial bonding and dispersion stability within the biofilm matrix. FT‐IR spectroscopy confirmed CNF's integration, while XRD analysis highlighted its high crystallinity, contributing to effective reinforcement. The addition of CNF significantly improved the tensile strength, modulus, and elongation at break, with optimal performance at 5% CNF loading. Beyond this, mechanical properties declined due to CNF agglomeration, as observed in SEM micrographs, which showed microcracks and rougher surfaces at higher loadings. Thermal stability, assessed via TGA, improved with CNF loading, with SRC biofilms demonstrating superior resistance to thermal degradation compared to RS biofilms. These findings indicate that CNF‐reinforced RS and SRC biofilms, particularly at 5% CNF loading, offer enhanced mechanical and thermal properties, positioning them as promising materials for sustainable packaging. Further optimization could broaden their applications in industries such as biomedicine and food preservation. Highlights RS and SRC biofilms explored as eco‐friendly plastic packaging materials. CNF loading enhances biofilm properties for RS and SRC‐based films. SRC biofilms exhibit improved flexibility and durability over RS biofilms. Optimal CNF loading (1%–5%) enhances thermal stability of SRC biofilms. Crack resistance in SRC biofilms confirms strong CNF‐carrageenan structure.