Cellulose is the primary structural component of cardboard, making up around 90% of its composition. It is a linear polymer of glucose molecules, with a formula of (C6H10O5)n. Cellulose molecules are arranged in a highly ordered crystalline structure, which gives cardboard its strength and rigidity.

2. Hemicellulose

Hemicellulose is a group of branched polysaccharides that are also found in the cell walls of plants. In cardboard, hemicellulose acts as a binder, helping to hold the cellulose fibers together. Hemicellulose is composed of various sugars, including xylose, mannose, and galactose.

3. Lignin

Lignin is a complex organic polymer that is found in the cell walls of plants. In cardboard, lignin provides strength and stiffness. It is also responsible for the brown color of cardboard. Lignin is composed of various phenolic compounds, such as coniferyl alcohol, sinapyl alcohol, and p-coumaryl alcohol.

4. Starch

Starch is a polysaccharide that is used as a binder in cardboard. It is composed of glucose molecules that are linked together in a branched structure. Starch is derived from plants, such as corn, potatoes, and wheat.

5. Waxes

Waxes are fatty substances that are used to coat cardboard and make it water-resistant. Waxes are typically derived from plants, such as palm trees, carnauba palms, and beeswax.

6. Pigments

Pigments are used to add color to cardboard. They can be either natural or synthetic. Natural pigments are derived from plants, minerals, or animals. Synthetic pigments are man-made chemicals.

7. Additives

Additives are chemicals that are added to cardboard to improve its properties. Some common additives include flame retardants, waterproofing agents, and antimicrobial agents.