Green Composites From Plasticized Cellulose Acetate Filled With Inorganic Fillers and Natural Fiber for Rigid Packaging Applications: Effect of Low Acetyl Content and Bio‐Based Plasticizer

ABSTRACT This work aims to improve the processing window and melt strength of cellulose acetate (CA) with low acetyl content as a greener alternative to non‐biodegradable plastics for rigid‐packaging applications. It presents the first scientific evaluation of inorganic and organic fillers on plasticized CA (pCA) using two plasticizers, bio‐based triacetin (pCTA) and petro‐based triethyl citrate (pCTEC). Low‐acetyl CA is used to improve biodegradability over conventional high‐acetyl CA. Melt extrusion followed by injection molding is performed to make pCTA and pCTEC, and composites are formulated with organic/inorganic fillers including talc, clay, calcium carbonate (CaCO 3 ), and microcrystalline cellulose (MCC). Talc‐based composite reveals a well‐balanced mechanical performance and is thus combined with luperox (LUP), which further increases the matrix's tensile strength and Young's modulus. The pCTEC/10 wt.% talc shows ~130% rise in maximum extensional viscosity, while pCTA/0.01LUP/10 wt.% talc achieves a ~70% gain. The pCTEC/0.01LUP/15 wt.% talc improves the water vapor and oxygen barrier by 55.1% and 58.1%, respectively. Talc's platy morphology enhances interfacial adhesion, and its easier delamination in LUP's presence contributes to these barrier improvements. CA's thermal degradation shifts ~10°C higher after the addition of LUP and talc. These enhancements demonstrate the potential of pCA‐based composites for sustainable rigid packaging applications.