Cellulose Acetate

Cellulose acetate (CA), as an insoluble cellulose derivative, is regarded as a nontoxic, nonirritant, and biodegradable material which is derived from the acetylation of the plant substance cellulose. In the structure of cellulose acetate (figure 1), the acetyl content ranges from 29.0% to 44.8%, corresponding to diacetate (cellulose diacetate, CDA) and triacetate (cellulose triacetate, CTA).

Fig. 1 General structure of cellulose acetate

Synthesis of Bio-based Cellulose Acetate

The traditional acetylation process (figure 2) to produce cellulose triacetate consists of pretreatment with glacial acetic acid and sulfuric acid as a catalyst, followed by the actual acetylation reaction with acetic anhydride and finally the purification of the product by washing with distilled water. Cellulose diacetate can be produced by the acid hydrolysis of cellulose triacetate ^[1].

Fig. 2 General schematic of acetylation process for production of cellulose acetates

Degradation of Bio-based Cellulose Acetate

Cellulose acetate is a versatile bio-based polymer derived from natural resources offering unique features, including hardness, good impact resistance, optical transparency, resistance to hydrocarbons and lack of static electricity. Besides, it is biodegradable under a variety of environmental conditions, naturally sourced and eco-friendly manufactured, suitable for a variety of applications. Figure 3 presents the possible lifecycle of cellulose acetate polymers and factors affecting the degradation process ^[2].

Fig. 3 (a) Possible lifecycle of cellulose acetate polymers and (b) factors affecting the degradation process

Exposure to the environment (e.g. sunlight, mechanical wear due to wind or waves, lake-or seawater, soil, compost and micro-organisms) causes chemical and physical changes in polymeric materials. These changes can with time be observed both at molecular level and at macroscopic level. The potential degradation pathway of cellulose acetate is showed in figure 4 ^[2].

Fig. 4 The potential degradation pathway and simple testing strategies adopted for evaluating the degradation of cellulose acetate

Applications

Cellulose acetate is adequate as membrane materials, because of the advantages such as moderate flux, high salt rejection properties, cost effectiveness, relatively easy manufacture, and non-toxicity. For example, cellulose acetate membranes can be used in the water desalination, in the hemodialysis process, and in the controlled drug release.

In addition, cellulose acetate is widely used in many other applications. For example, it can be used in textiles; it can be used in cigarette filters to absorb vapors and accumulate particulate smoke components; it can be used as an additive in surface coatings and inks; and it can be used as a carrier in photographic negatives, motion picture film (celluloid), microfilm, microfiche and audio tape.

Our Bio-based Cellulose Acetates

Alfa Chemistry provides a range of cellulose acetates which are based on renewable raw materials.

Alfa Chemistry is a professional supplier of bio-based cellulose acetate. For high quality products, professional technical service, use suggestion and latest industry news, please feel free to contact us.

References

1. Risto Hertzberg. Cellulose acetate production from Finnish hardwood and softwood dissolving pulp. Aalto University, 7th of November, 2019.
2. Yadav, N., & Hakkarainen, M. Degradable or not? Cellulose acetate as a model for complicated interplay between structure, environment and degradation. Chemosphere, 2020, 128731.

Our products and services are for research use only.