Impact of Acetylation, Ethylene Glycol Plasticization, and Rice Husk Ash Reinforcement on Manihot Esculenta Crantz CV. TMS 92/0326 Starch-Based Bioplastic Films

Abstract: This study analyzes the effect of acetylation, plasticization with ethylene glycol and rice husk ash - filler reinforcement on the properties of the Manihot esculenta Crantz cv. TMS 92/0326, a variety of cassava, used in starch films at different concentrations of plasticizer (2, 3, 4, 5 g/100 g starch), and with rice husk ash (0, 0.5 g and 1 g/100 g starch; respectively). Also, the combined effects of plasticizer and filler concentration on tensile strength were analyzed. The results indicate that the percentage (%) yield of extracted starch was high (85.2%) as expected for this species (Manihot esculenta Crantz cv. TMS 92/0326 variety) of Cassava. The modification by acetylation reduced the temperature of gelatinization of the cassava starch from 63°C (extracted-native starch) to 55°C, leading to better processability and flexibility of the films, in addition the percentage (%) yield after modifications as well was decreased to 79% with the substitution of hydroxyl groups with acetyl groups in the starch molecules. The results also suggest that increasing rice husk ash content has a favorable effect on water and acid resistance, with better performance at 1.0 g of filler . Despite this modifications and reinforcement of the films , they remained soluble in 1M NaOH, indicating their deterioration in alkaline environments.. Colour of all films were white to milky (high ethylene glycol level), with thickness being the same for all formulations (0.41–0.53 mm). The tensile strength test also revealed significant improvement in the films with rice husk ash reinforcement (2g of ethylene glycol and 1g of rice husk ash) having the highest tensile strength of 9.05 MPa. This formulation showed good compromise between flexibility and tensile strength. Nonetheless, greater plasticizer content resulted in decreased tensile strength, suggesting that there could be a compromise between flexibility and strength. FTIR data confirmed successful acetylation with ester groups observed at 1740 cm⁻¹. These results show that optimal combinations of acetylation, plasticization and rice husk ash filler strengthening efficiently balance flexibility, strength and acid, alkaline, moisture and water resistance. This result makes this formulations a Promising alternative for biodegradable packaging materials.