Polymers are formed from simpler molecules that are joined into large molecules that behave differently than the smaller molecules alone. Cellulose is made up of simple molecules that are linked together like chains, while lignin is made up of more complex molecules that are linked like circles or rings. The cellulose chains are easy to break apart, but the lignin rings are difficult to break apart because lignin acts like glue to make wood stiff so that trees can grow and stand upright.
Cellulose and lignin are usually separated from each other when wood is being processed to make paper. Cellulose is white in color, while lignin is dark in color. Most paper products are required to be white or very light in color like printing paper and paper plates, and these products are primarily made from cellulose. However, sometimes the visual quality of the final paper product does not need to be very light in color, so these paper products are made from both cellulose and lignin.
These products include newspaper and brown paper grocery bags. Lignin can turn yellow in color when it is exposed to oxygen or air especially in the presence of sunlight. The molecules in lignin will change and the circular links will become less stable.
He produced a sample and, in , received a German patent for it. In fact, some historians credit Keller for the invention more than Fenerty simply due to the fact that he received a patent and the Canadian did not.
Within thirty years, wood pulp paper was all the rage on both sides of the pond. While wood pulp paper was cheaper and just as durable as cotton or other linen papers, there were drawbacks. Most significantly, wood pulp paper is much more prone to being effected by oxygen and sunlight. Wood is primarily made up of two polymer substances — cellulose and lignin.
Cellulose is the most abundant organic material in nature. It is also technically colorless and reflects light extremely well rather than absorbs it which makes it opaque ; therefore humans see cellulose as white. However, cellulose is also somewhat susceptible to oxidation, although not nearly as much as lignin. Oxidation causes a loss of electron s and weakens the material. Lignin is the other prominent substance found in paper, newspaper in particular. Lignin is a compound found in wood that actually makes the wood stronger and harder.
In fact, according to Dr. Hou-Min Chang of N. Lignin is also highly susceptible to oxidation. Exposure to oxygen especially when combined with sunlight alters the molecular structure of lignin, causing a change in how the compound absorbs and reflects light, resulting in the substance containing oxidized lignin turning a yellow-brown color in the human visual spectrum.
Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Physical Science. Chemical Processes and Tests. Why do newspapers turn yellow over time? Lignin makes wood stiff and trees stand upright. It eventually turns paper yellow because of oxidation. Why doesn't paper money disintegrate when it gets washed in the washing machine?
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