Cassava starch-based bioplastics reinforced with organic microparticles: Synthesis and characterization

Managing plastic waste remains a significant global challenge. As a result, there is an increasing search for alternative materials to replace synthetic plastics. Bioplastics (BP) made from cassava starch have emerged as promising biodegradable and environmentally friendly options. Nevertheless, these materials exhibit limited stability in moisture-rich environments and require further modification. This study reports, the first systematic study of < 63 µm coconut shell microparticles on glycerol-plasticized cassava starch bioplastics with comprehensive property profiling. Characterization methods included water absorption, moisture content, solubility in water and alcohol, biodegradability assessments, Fourier-transform infrared spectroscopy (FT-IR),tensile testing and morphology study. Results indicated that water absorption dropped significantly as CSMp content increased, with an 85.67 ± 0.49% reduction observed between unfilled bioplastics (BP-3.0) and filled bioplastics (BPF-8), demonstrating improved resistance to water molecules. Moisture content also decreased from 18.12 ± 0.49% in unfilled samples to 17.10 ± 0.35% in microparticle-enhanced bioplastics, indicating better water stability due to the organic microparticles. Although solubility in water remained higher than in alcohol and was unaffected by CSMp addition, the microparticles impacted biodegradability; bioplastics with higher microparticle content experienced less weight loss during biodegradation compared to those with lower CSMp levels. A positive correlation was observed between biodegradation and moisture content. FT-IR spectra confirmed the presence of characteristic functional groups. The CSMp decreased the Tensile strength of the BPF compared to the BP-3.0 The morphology of the bioplastics demonstrated an increasing dispersion of the microparticles in the bioplastic from BP-3 to BPF-4. The improved water-resistant properties of CSMp-reinforced cassava starch bioplastics suggest their potential use in the food packaging industry.