Paper Making Process and Recycling Waste Papers
What You Need to Know
Fiber is a hairlike strand of material that is much longer than it is wide. Plant fiber is made of dead plant cells that are long, narrow, and tapered (gradually narrower toward the end) at each end. Fiber cells are made mostly of the chemicals cellulose and lignin. Paper is a thin sheet made from pulp, which is a mixture of water and separated plant fibers. Recycle means to process a material so it can be used again.
How Does Papermaking Work?
Plant fibers are threadlike strands of dead cells that are characterized by an elongated shape and a thick cell wall composed mainly of cellulose and lignin. In plant fibers, such as wood, the tapered ends of the cells overlap. The length of the fiber depends on the number of cells that make it up. Fiber length varies from one type of plant to another. Wood fiber used for papermaking is generally about 1/10 inch to 1/4 inch (2.54 mm to 6.35 mm) in length. Mixing short and long fibers increases paper strength.
Most paper is made with wood fibers. After grinding and treating the fiber with various chemicals, only cellulose is left in it. This fiber plus water is called pulp. Next, the pulp goes through a process to separate the individual wood fibers. The mushy pulp mixture is sprayed onto a long, wide screen, called a wire. Water starts to drain out of the holes in the wire. This water is collected and recycled to make more pulp. As the water drains, the wood fibers begin to stick together, forming a very thin mat on the wire. Felt-covered rollers are used to absorb more of the water. But the pulpy mat on the wire is still about 60 percent water. The wire is now passed through hot rollers. The rollers heat and dry the wet mat, sealing the fibers closer and closer together, gradually changing them from pulp to paper. A big heavy roller presses the dry paper to make it smooth and uniform in thickness. The paper might then be coated with a fine layer of clay to make it glossier and easier to print on. After some more drying, the paper-making process is complete.
What Does This Have to Do with Recycling Paper?
In recycling, pulp is made by mixing wastepaper with water. Wastepaper that has never been used is called mill broke. If recycled paper contains more than 25 percent mill broke pulp, it is not considered recycled. Wastepaper that has print on it is called postconsumer waste. It is more difficult to recycle this type of paper because the ink has to be removed during the recycling process.
Some insects, such as paper wasps and yellow jackets, make paper nests. They mix their saliva with fibers scraped from dead wood until a pulp similar to papier-mâché is formed. The nests contain a single layer of six-sided chambers that fit neatly together, like the cells of a honeycomb. Caution: Don't ever disturb a wasp's or a bee's nest. Wasps and bees are easily provoked and can sting forcibly, causing much pain, as this author can testify.
Real-Life Science Challenge
Paper makes up a large percentage of the waste in landfills in the United States. Recycling paper is one way to reduce the amount of trash in landfills. Recycled paper also helps save energy and water because most of the energy and water in papermaking is used to change wood into pulp. Paper can be recycled only 4 to 6 times. This is because with each recycling, the fibers get shorter and weaker.
Now pulp must be mixed with the recycled fibers to maintain the strength and quality of the paper.
Now, start experimenting with papermaking. Which paper is easiest to recycle? Which makes the best recycled paper? What about a mixture of different kinds of papers?
- Research the history of papermaking.
- Collect scraps of different types of paper.
- Make pulp by mixing water with bits of wastepaper.
- How can you safely remove the ink from used paper?
- How will you dry your paper?
Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.