Chemistry · Chapter 25
Study notes aligned to the official NEB syllabus.
Paper is a thin, flexible sheet material made mainly from cellulose fibres obtained from plant sources. The fibres are separated from wood or other plant material as pulp, and then reformed into sheets on a paper-making machine. Good papermaking fibre needs to be long, rich in cellulose, and low in lignin (the woody material that binds fibres together in the plant and, if not sufficiently removed, makes paper weak, brittle and yellow with age).
| Category | Examples |
|---|---|
| Softwood | Pine, fir, spruce |
| Hardwood | Eucalyptus, mulberry, rubber-plant wood |
| Grasses and reeds | Lemon grass, situ, panni, bamboo |
| Straw | Rice straw, wheat straw, barley straw |
| Recycled fibre | Waste/recovered paper |
Bamboo is particularly valued as a papermaking raw material, especially when blended with hardwood, because it combines long fibres with high cellulose content and relatively low lignin, giving a good balance of strength and processability; it is widely used in tropical and sub-tropical countries where suitable softwood is scarce. Recycled waste paper is also an important raw material, since it can supply a large share (commonly cited as around two-thirds) of the fibre used in modern paper production, reducing the demand on fresh timber.