paper (chemistry in our daily life)

Paper

Discussing about chemistry in daily life is a very complicated story because nowadays chemistry is in every single thing around us. We can feel chemistry everywhere in the house like bathroom and kitchen. Soap, toothpaste, plastic bag and perfume are some examples of chemical things in our daily life but I am going to write about paper. Chemistry has connected natural things with chemical things and paper is one of the most important things in this case. As we know paper Is made from woods and woods is in nature so what is the relation between paper and chemistry. It is only possible to use the paper if it passes some chemical reactions and that’s the topic I am going to write about it.

First of all let me give you some introduction about how paper is made from woods but before it a little history of how paper been created by humans in many years ago

Papermaking has been around 4,000 years. The Egyptians had a process of making papyrus, a plant based paper product. The Chinese in the 2nd century BC had a paper making process involving a fibrous matter. In the 8th century, Arabs had learned the art of paper making.

But how is it made? Although the process has been refined over the years, the process today is less due to innovation than to efficiency of existing processes. It uses wood and it consists of eight stages: debarking, chipping, pulping, bleaching, paper machine, blade coater, super calendar, and sheet converting.

1. Debarking

Because the process starts with cutting trees, the bark from trees must be removed before the wood can be used for papermaking. A large, spinning and rotating drum that makes the logs move around is used to debark the trees. As the logs rub against each other, the bark comes off.

2. Chipping

Before the logs are pulped, they are cut into small pieces or chips. A large rotating knife goes in circles and cuts the logs into chips.

3. Pulping

The pulping process separates the cellulose and hemi-cellulose from the lignin and removes other tree oils and resins. This process is important because the remaining fibers are used to produce the product we know as paper.

4. Bleaching

Bleaching is a very important step. Bleaching is used to purify and clean the pulp. Bleaching removes lignin, which affects the purity of the fiber. Kraft mills use chlorine gas and chlorine dioxide to bleach pulp, while most mechanical pulp bleaching operations

Use peroxide. Chlorine gas removes most of the remaining lignin, while the chlorine dioxide whitens lignin that cannot be removed.

5. Paper Machine

The paper machine involves four sections. It starts with a step called stock preparation. During stock preparation, wood fiber is mixed with water and minerals in a mixture that is more than 99% water. When the water drains, a web of paper is formed. The next step is the press section. Here the paper is squeezed between rollers and a felt (a large mat of nylon and polyester filaments). This removes more water from the paper. After the press section, 40-50% of the paper is still made up of water. In the third section, the dryer section, dryers remove even more water from the paper. After the dryer section, only 2-6% of the paper is made up of water. In high-quality machines, a size press coating is put onto the paper next. A size press coater applies a light coating of starch and minerals. This makes the paper even stronger and smoother. After the size press coating is put on, the paper is dried again in the after-dryer section. Finally, the paper is wound into a giant roll.

6. Blade Coater:

For coated papers, a blade coater puts a thin coating onto the finished paper. The paper glides under a blade that deposits a coating onto the paper surface. The different coatings make the paper very good to use in printing.

7. Supercalender:

This process makes the paper glossy and smooth. The supercalendering machine is made up of many large rollers. The rollers put the paper under a lot of pressure and heat it up. After supercalendering, the paper is cut into smaller rolls.

8. Sheet Converting:

Sheet converting is the last stage of papermaking. Some of the paper rolls are cut into sheets, while others are packaged for shipping to customers.

The steps outlined above have been around for centuries. The production techniques have been modified made more efficient, and cost effective. However, wood is still the basis of paper making, and that is an old product.

These are the stages to make a paper but paper also has came to our life in other shapes like tissues, cardboard and many other shapes.

Paper Use is like Energy Use, how? Paper can be thought of as a form of energy. This can make it easier to grasp the power of ideas of 'paper use' and 'paper efficiency', showing how we can measure and change them. It also links cutting paper use to reducing energy use, for which we have good public policies and programs to address. Paper use is also like energy use in the production energy it embodies. As explained in our discussion of the environmental issues around paper use, a typical office worker uses the equivalent of an 80 W light bulb of electricity in office paper use, but at a cost many times the light bulb cost. And now I will give you lists of some chemicals in papermaking

CHEMICALS USED IN PULP & PAPER MANUFACTURING AND COATING

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Common Name	Chemical Name	Chemical Formula	Used For	Specific Density	Other Characteristics
Agalite or Talc	Silicate of Magnesia	MgO-32%, SiO2-62%	It gives paper a greasy or soapy feel. and enables it to take a high finish.	2.6 - 2.8	A natural fibrous form of talc, gray in color.
AKD	Alkyl Ketene Dimer		Sizing
Alum	Sulfate of Alumina	Al2(SO4)3.18H2O	For alkaline sizing along with Rosin	1.62
Albarine	Natural Sulfate of Lime	CaSO4.2H2O - 100%	A calcium salt that is used for a variety of purposes including: building materials.	2.4
Ammonium Zirconium Carbonate (AZC)	Ammonium Zirconium Carbonate	CH2O3NH3Zr	Used as in-solubilizer, crosslinker & hardener	1.36	AZC is a clear, usually colorless solution, having an odor of ammonia and a pH of approximately 9.5. As a carbonate, it will react with acids, and so should not be used in coating systems below pH 7. In storage, it is stable for up to six months.
Anthraquinone	Anthraquinone	C14H8O2	Added to white liquor (alkaline cooking liquor) to improve pulp yield and to increase the rate of delignification.	1.44	yellow crystalline powder
Anti-Foam/Defoamer			To prevent foam (anti-foam) or to destroy it once it has formed (defoamer).		Surface active, but highly insoluble in water.
Asbestine	Silicate of Magnesia	MgO-32%, SiO2-62%	It is used as a loading agent in paper manufacture, particularly for blotting papers and board.	2.6 - 2.8	A mineral compound of almost pure fibrous magnesium silicate, which possesses physical characteristics between those of talc and asbestos.
APE	Alkylphenol Ethoxylates	CH3(CH2)n(C6H4) (OCH2CH2)m-OH	Used as cleaning agents or surfactants
ASA	Alkenyl Succinic Anhydride		Sizing
Barium Sulfate	Barium Sulfate	BaSO4 - 100%	Used as a pigment	4.2-4.5	White insoluble powder.
Barytes	Barium Sulfate	BaSO4 - 100%	Used as filler	4.2-4.5
Blanc Fixe	Barium Sulfate	BaSO4 - 100%	Used as a base for watercolor pigments and as a filler in paper.	4.2-4.5	Powdered barium sulfate
CMC	Carboxy Methyl Cellulose		Sizing
Caustic Lye or Caustic Soda or Lye	Sodium Hydroxide	NaOH	Pulping and to maintain pH
Chalk (Precipitated)	Precipitated Calcium Carbonate	CaCO3 - 100%	Filler particularly with acidic sizing.	2.7-2.9	High Brightness & Opacity
Chalk (French or Spanish)	Silicate of Magnesia	4MgO+5SiO2+H2O; MgO - 33%; SiO2 62%		2.6-2.9	A soft white compact talc

After discussing about chemicals in papermaking let me write a little about how Recycling can help the Earth.

If you recycle paper, you save trees, which in turn reduces the amount of carbon dioxide in Earth's atmosphere and reduce global warming. Trees photosynthesise, where they take in carbon dioxide in the atmosphere and give out oxygen. Carbon dioxide is the main reason for global warming as it traps the Sun's heat in Earth's atmosphere.

If you recycle aluminum, you save energy, as it takes much less energy to melt cans into fresh aluminum. Most energy comes from electricity produced by burning coal, so you cut down on carbon dioxide.

References:

http://www.essortment.com/all/paperhowismad_rrfn.htm

http://www.paperonweb.com/chemical.htm

by:ashkan mahbobibrojerdi 1001025754