Synthesis of Thermoplastic Materials Using Cellulose Acetate as a Backbone via Melt Kneading Extrusion

To develop a highly biomass-based thermoplastic resin using cellulose acetate (CA) derived from woody biomass as the base material, cellulose acetate-<i>graft</i>-polylactic acid (CA-<i>g</i>-PLA) composites were successfully synthesized by a transesterification reaction through the melt kneading method using 2-ethylhexanoic acid tin-(II) as a catalyst. Various characterization methods, such as Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H NMR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), were used to investigate the structure and properties of the as-prepared product. The results showed that the product was a grafted copolymer of CA and PLA, and PLA side chains were detected in the copolymer. From DSC analyses, the composite showed amorphous and its glass transition temperature (<i>T</i> _g) was around 120 °C. The injection molding temperature was 255-260 °C for CA, while that for the CA-<i>g</i>-PLA composites was 185-205 °C. Tensile tests demonstrated that the composites achieved a maximum tensile strength of 95.5 MPa and a maximum Young's modulus of 1.6 GPa, corresponding to 225 and 133% improvements, respectively, compared to neat PLA.