Catherine N. Muya^{1, 2,}, John M. Onyari¹, Lydia W. Njenga¹, Joab O. Onyango², Geoffrey Otieno², Bonface G. Mukabane³

Cellulose acetate was synthesized in a heterogeneous process from Grevillea robusta leaves. Cellulose fibers were extracted from the leaves and subjected to an optimized esterification process using response surface methodology (RSM). Glacial acetic acid was used as the solvent and acetic anhydride was used as the acetylating reagent with conc. H₂SO₄ as the catalyst. The achieved optimum percent weight gain (WPG) was 48.85 %, with a percent acetyl content (PAC) of 43.26 % and a degree of substitution (DS) of 2.82. Thermal gravimetric analysis (TGA), Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) were utilized to analyze and evaluate the cellulose acetate that was synthesized. The XRD results gave X-ray diffraction patterns of the cellulose before and after acetylation. The diffraction patterns obtained indicated a decrease in crystallinity of the native cellulose compared to cellulose acetate. FTIR analysis established the formation of ester bonds in cellulose acetate. The SEM micrographs obtained were characteristic of the cellulose acetate standard used as the reference. The TGA and DTG analysis data indicated an increase in the thermal stability of acetylated cellulose compared to the extracted cellulose. The study suggests that Grevillea robusta leaves, which are renewable and readily available, non-wood biomass are a sustainable supply of affordable, high-quality cellulose that may be used to make cellulose acetate. The cellulose acetate produced can therefore be used to synthesize sustainable biodegradable polymers and biocomposites which will contribute to solving the serious environmental pollution problem due to petroleum-based plastic waste management.

Acetylation, Optimization, Cellulose acetate, Sustainable biodegradable polymers, Biomass