Sustainable synthesis of chitosan-grafted microcrystalline cellulose derived from jute and shrimp shells via polycondensation reaction

The growing demand for sustainable, high-performance biocomposites has driven interest in microcrystalline cellulose (MCC) as a renewable reinforcing agent, derived from jute fiber. However, the strong hydrogen bonding between hydroxyl groups in MCC fibrils often leads to gel-like aggregation, which hinders the homogeneous dispersion of polymer matrices and compromises interfacial adhesion in composite materials. To address this limitation, we chemically modified MCC by grafting it with chitosan (CS), thereby enhancing its compatibility with polymeric systems while retaining biodegradability. The grafting reaction was performed via polycondensation in toluene, using para -toluene sulfonic (p-TSA) acid as a catalyst and potassium persulfate (KPS) as an initiator. The structural, morphological, and thermal properties of MCC, CS, and CS-grafted MCC (CS-g-MCC) were systematically characterized using FTIR, SEM, WXRD, and TGA. FTIR confirmed grafting by forming bonds between the hydroxyl groups of MCC and the amino groups of CS. At the same time, SEM revealed a transformed surface morphology in CS-g-MCC, exhibiting a rougher, more heterogeneous texture compared to pristine MCC. WAXD analysis revealed a distinct reduction in crystallinity after grafting, indicating the presence of an amorphous CS layer on MCC. Notably, TGA demonstrated improved thermal stability of CS-g-MCC, with a 15–20 % higher decomposition onset temperature than pure MCC. These findings confirm that CS grafting effectively modifies the surface properties of MCC, addressing dispersion and interfacial adhesion challenges in composite applications. The study provides a sustainable pathway to valorize agro-industrial waste (jute and shrimp shells) into functional biomaterials, with potential uses in packaging, biomedical scaffolds, and adsorbents. Future work will explore the performance of CS-g-MCC in polymer nanocomposites.