Effect of Kaolinite filler and Ethylene Glycol Plasticizer on the Absorption and Mechanical Properties of Carboxymethyl modified Cassava Starch Bioplastic Films

Abstract

This study examines how kaolinite filler and ethylene glycol (EG) plasticizer influence the absorptive and mechanical behaviour of carboxymethyl cassava starch (CMS) bioplastic films. The carboxymethyl cassava starch bioplastic films were fabricated using casting method by varying ethylene glycol plasticizer (2 g, 3 g, 4 g, 5 g) and varying kaolinite filler (0 g, 0.5 g and 1 g) for each weight of ethylene glycol making a total of 12 samples. The samples were evaluated for water absorption, moisture absorption, acid resistance, as well as
mechanical properties such as tensile strength, elongation-at-break, and yield point. Water and moisture absorption increased with ethylene glycol concentration, while kaolin moderated hydrophilicity by enhancing structural stability. Acid resistance improved significantly with kaolin addition, confirming its barrier effect. Mechanical data revealed that increasing ethylene glycol enhances elongation at break but reduces tensile strength at high concentrations, whereas kaolin improves tensile strength but reduces flexibility. Optimal mechanical performance occurred at 3 g ethylene glycol with 1 g kaolin. These findings demonstrate that carboxymethyl cassava starch -based films can be optimized for targeted packaging applications by adjusting plasticizer–filler balance.