Alexander Ach

Biodegradable Plastics Based on Cellulose Acetate

Abstract It is generally known that secondary cellulose acetate (with 53 to 56% acetyl groups) is suitable for thermoplastic processing. With appropriate plasticizers a plastic material is obtained which excels in transparency and pleasant texture, and it is therefore often used for tool handles, combs, spectacle frames, and the like. In principle, cellulose acetate with such a degree of substitution is biodegradable, although degradation proceeds extremely slowly. However, when common plasticizers are substituted by specific esters and other low molecular components (at least 30% by weight), the “plastic material” has the same thermoplastic properties but will decompose in soil or water within just a few years. For example, a cellulose acetate cup buried in sewage sludge lost more than 70% of its original weight within about 18 months. In an aqueous environment (Sturms test), the decomposition amounted to more than 60%. Under appropriate composting conditions or conditions of anaerobic fermentation, the...