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The Challenge: Make Paper and Ink



Telephone books and newspapersHow is the plant material prepared for paper making?

Plant fibers are separated either mechanically — by pounding the plant material — or chemically — by soaking the plant material in a chemical bath. In practice, a combination of mechanical and chemical pulping is often used.

Mechanical Pulping

Plant material or wood chips are ground up and mixed with hot water and steam. The heat softens the lignin, and grinding pulls the fibers apart. This damages the fibers and makes them shorter and weaker, so paper made this way is not strong. Mechanical pulping does not remove parts of the plant which are not cellulose (or other impurities), so this method is usually used for newspaper and telephone directories.