Polylactide/Cellulose Acetate/Triethyl Citrate Blends and the Effect of Cellulose Acetate Percentage on Blend Properties

Polylactide (PLA) is a bio-based, biodegradable polymer. Its relatively high tensile strength and stiffness make it a competitive option in the packaging industry. The greatest drawback to PLA which prevents its use in some applications is its brittle nature as evidenced by low impact strength and elongation at break. Efforts have been made to improve its toughness, including copolymerization of lactide with other monomers. Unfortunately, many methods used to toughen PLA can compromise its eco-friendly nature by increasing its carbon footprint and/or preventing eventual degradation. Cellulose acetate (CA) is another well-known bio-based and biodegradable polymer that is an organic acid ester of cellulose. Triethyl citrate (TEC) is an ester of citric acid. It is a natural compound that is nontoxic, acceptable for food packaging applications, and has been shown to plasticize both PLA and CA. The current work examines blends of PLA, CA, and TEC in varying percentages and examines the plasticizing effect of TEC on various properties of the blend including elongation at break, glass transition temperature, and modulus of elasticity. The goal of this work is to improve the properties of PLA without compromising PLA’s novelty as an eco-friendly, petroleum-based polymer alternative.