Cellulose acetate (CDA) cannot be processed as raw material because it starts to decompose before melting. Triacetin and diacetin were tested to improve CDA processing versus conventional phthalate as environmentally sustainable plasticizers, because of their low toxicity and fast biodegradability. The addition of triacetin and diacetin allowed melt processing of CDA and the results of tensile tests outlined their effect as plasticizers. The values of mechanical properties were compatible with the requirements for applications in rigid packaging. From the results of biodegradation tests it can be concluded that for pure cellulose acetate, complete biodegradation was obtained within 200 days of testing after reinoculation. Incomplete biodegradation was observed for test items with 20% triacetin or with 30% phthalate. After 46 days of incubation, the test samples with 30% plasticizer based on triacetin or triacetin-diacetin were completely biodegraded. These formulations can be selected for the production of compostable blends and/or biocomposites.