Development of Cellulosic Bioplastic‐Based Biocomposites for Biodegradable Packaging Applications: Effect of High Acetyl Content and High Filler Loading

ABSTRACT

Cellulosic bioplastics have attained significant interest because of their biodegradability and biocompatibility. Therefore, this work explores the influence of inorganic fillers (mineral fillers) on cellulosic plastic (plasticized cellulose acetate [pCA]) to evaluate its potential as a sustainable substitute to conventional petroleum‐based plastics for rigid packaging. Cellulose acetate (CA) was plasticized using an eco‐friendly plasticizer, triacetin, which broadened the narrow processing window of CA and helped in achieving stable melt extrusion. The biocomposites were processed via extrusion followed by injection molding. Calcium carbonate (CaCO ₃ ), kaolin, and talc were incorporated as fillers, and the effects of these fillers on the thermal, mechanical, rheological, dimensional, and barrier properties of pCA biocomposites were analyzed. Talc outperformed all the inorganic fillers, demonstrating an increase in tensile modulus (127%), tensile strength (21%), flexural modulus (87%), flexural strength (29%), and barrier properties (water vapor barrier by ~60% and oxygen barrier by 58%). The heat deflection temperature of the pCA matrix increased as a result of reinforcing with talc. Dimensional stability was also improved with talc addition, as observed by a reduction in the coefficient of linear thermal expansion by 22% in the normal direction and 29% in the flow direction in comparison to neat pCA. Furthermore, rheology and morphological analysis reflected strong filler–matrix interactions. These findings highlight the potential of pCA‐based composites in advancing the use of biodegradable and sustainable materials for rigid packaging applications.