The Chemistry of Making Paper

Pulp is the collection of fibers liberated from plants during the pulping process.

Paper is a thin, flexible web consisting of cellulose fibers deposited upon each other and then dried to form hydrogen-bonds between the layers of plant fibers.

Cellulose fibers are polymers of six-carbon sugars, glucose, made during photosynthesis. For the production of cellulose, the plant converts each glucose into a six-membered ring and then links the rings together to form a linear polymer chain.

Attached to the surface of this polymer are hydrogen atoms (H) and hydroxyl groups (OH). Look up the electronegativity values for oxygen and hydrogen.

Element Electronegativity value

Oxygen

Hydrogen

Which one of these elements attracts bonding electrons more? Explain your answer.

On the hydroxyl group below, indicate which end of the group has a partial negative charge (d^-) and which has a

partial positive charge (d⁺)

O – H

A hydrogen bond is the attraction of a partial negative (d^-) end of a group with the partial positive (d⁺) end of another group.

Illustrate how two hydroxyl groups can form a hydrogen bond. It can be said that the OH groups are trying to be like water and are looking for H groups to do so.

In the wet fibers, the hydroxyl groups along the cellulose chain are associated with hydrogen atoms on the water molecules, as shown below.

Smook’s Handbook, 1982, adapted

For this reason, cellulose fibers are hydrophilic (water loving). In order to bond fibers together and form paper, it is necessary to bring the fiber very close together and remove almost all of the water in the fibers so that the hydrogen bonds between the fibers and water can be converted to hydrogen bonds between fibers.

Nothing has to be added to paper to get the fibers to bond together. When dried, the fibers bond themselves together through hydrogen bonds.

Illustrate what happens if you put the paper back into the water after it is dried.

Hydrogen bonds may seem small, but are very strong!