Strategic fabrication of SEBS composite with high strength and stretchability via incorporation of polymer-grafted cellulose nanofibers for biomedical applications

SEBS (polystyrene- b -poly(ethylene- co -butylene- b -polystyrene)) has attracted significant interest in the biomedical and healthcare sector owing to its oxidative resistance, hydrolytic stability, sterilisability, non-toxicity, and optical clarity. Utilizing biocompatible nanofillers to enhance mechanical performances and durability of SEBS-based biomedical devices has been a vital research area. In this work, plant-derived cellulose nanofibers (CNFs) were used as a toughening agent, with maleic anhydride grafted SEBS (mSEBS) as a compatibilizer for the SEBS matrix. The surface modification of CNFs was accomplished in a one-step reaction using a nonaqueous medium. For varied ratios of CNFs to mSEBS, spectroscopic, microscopic, and gravimetric analyses were conducted to confirm the esterification reaction, the morphological changes, and the grafting efficiency, respectively. Subsequently, the modified CNFs (MCNFs) were added to pristine SEBS utilizing a scalable melt-blending technique. The hydrophobic polymer chains of mSEBS around CNFs inhibited self-aggregation and increased the dispersibility of CNFs in non-polar SEBS. With 0.2% MCNFs loaded composites, presented to improve the tensile strength, elongation at break, and fatigue life by 73%, 24%, and 83.5%, respectively. Compared to the unfilled system, the residual strain was reduced by 38% in the composite. Using L929 fibroblast cells, in vitro MTT testing revealed the cytocompatibility of developed nanocomposites. This work shows that polymer-grafting is a facile technique to introduce CNFs into non-polar matrices, and it has the potential to alleviate the durability problems associated with SEBS-based biomedical devices. Graphical abstract