What is the Difference Between Cellulosic and Protein Fibers

The main difference between cellulosic and protein fibers is that cellulosic fibers come from plants whereas protein fibers come from animals.

Generally, cellulosic and protein fibers are two types of natural fibers. Some other examples of natural fibers include cotton, wool, linen, and silk.

Key Areas Covered

1. What are Cellulosic Fibers
– Definition, Characteristics, Importance
2. What are Protein Fibers
– Definition, Characteristics, Importance
3. Similarities Between Cellulosic and Protein Fibers
– Outline of Common Features
4. Difference Between Cellulosic and Protein Fibers
– Comparison of Key Differences

Key Terms

Cellulosic Fibers, Protein Fibers

What are Cellulosic Fibers

Cellulosic fibers are fibers made up of ethers and esters of cellulose. Cellulose for the fibers comes from the bark, wood, or leaves of plants, or from other plant-based materials. In addition to cellulose, cellulosic fibers also contain lignin and hemicellulose. The main importance of cellulosic fibers is in the textile industry. Cellulose is a polymer with repeating glucose molecules attached end to end. Generally, the cellulose molecule is several hundred to over 10,000 glucose units long. It is similar to other complex carbohydrates such as starch and glycogen. However, cellulose is a straight-chain polymer.

Figure 1: Cotton

Furthermore, cotton and linen are two popular examples of cellulosic fibers. Cotton fibers look like soft, fluffy cotton balls while linen fibers look like strong, fibrous strands.

What are Protein Fibers

Protein fibers are a group of animal fibers such as wool and other animal hair, and insect fibers like silk. These fibers contain a high sulfur percentage of around 5wt.%. Animal hairs contain high cystine content, distinguishing them from silk. Total hydrolysis of the protein fibers keeps all of the twenty amino acids. Therefore, protein fibers are made up of condensation of alpha amino acids. They contain polymerized amide units with various substituents of the alpha carbon atom.

Figure 2: Wool

Moreover, protein fibers have moderate strength, resiliency, and elasticity. They also have excellent water-absorbing abilities. There are two types of protein fibers: keratin fibers like hair and fur and secreted fibers like silk. Normally, silkworm undergoes silk secretion.

Similarities Between Cellulosic and Protein Fibers

• Cellulosic fibers and protein fibers are two types of natural fibers.
• Some examples of natural fibers include cotton, wool, linen, and silk.

Difference Between Cellulosic and Protein Fibers

Definition

Cellulosic fibers refer to fibers structured from cellulose, a starch-like carbohydrate, while protein fibers refer to a group of fibers made up of animal fibers.

Origin

Usually, cellulosic fibers have a plant origin while protein fibers have an animal origin.

Content

Cellulosic fibers contain cellulose in higher amounts and hemicellulose and lignin in lower amounts while protein fibers contain alpha amino acids, forming polypeptide chains.

Examples

Cotton and linen are examples of cellulosic fibers while wool and silk are examples of protein fibers.

Conclusion

In brief, cellulosic fibers and protein fibers are two types of natural fibers important in the textile industry. Usually, cellulosic fibers have a plant origin while protein fibers have an animal origin. Cellulosic fibers contain cellulose in higher amounts and hemicellulose and lignin in lower amounts. Some examples of cellulosic fibers include cotton and linen. Protein fibers, on the other hand, have an animal origin. Generally, they are made up of amino acids and these fibers are polypeptide chains. Significantly, the two main types of protein fibers are keratin fibers like hair and fur and secreted fibers like silk. Keratin fibers contain higher amounts of cysteine. Therefore, the main difference between cellulosic and protein fibers is their origin.

References:

1. “Natural Fiber.” Wikipedia, Wikimedia Foundation, 18 Oct. 2022.
2. “Natural Protein Fibres.” Textile School, 29 Oct. 2018.

Image Courtesy:

1. “Kapok seeds I IMG 8004” By J.M.Garg – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Royal Winter Fair Wool 2” By Rob – Own Work (CC BY 2.0) via Commons Wikimedia