What causes paper to yellow as it ages?

Video Why Paper Turns Yellow A large part of our cultural history has been preserved on paper. However, this legacy is not immune to deterioration due to the passage of time. As the centuries go by, paper must be kept under ideal conditions of moisture and sunlight to prevent yellowing and cracking. Dr Adriano Mosca Conte of the University of Rome Tor Vergata and colleagues set out to find out what molecular structures form in paper that contribute to paper yellowing. They wrote about their results in Physical Review Letters on April 9, 2012. With the knowledge gained during their research, the process used to preserve the ancient manuscripts is promoted. strong. The oldest surviving examples of paper originate in China in the 2nd century BC. The processing of plant materials to create paper is believed to have originated in that region. From there, it spread through the Middle East and eventually made its way to Europe in the 13th century. The cheap mass production of paper in the 19th century essentially greatly increased literacy rates in the countries. the region participated in the Industrial Revolution and it could be argued that it is the foundation of our educated society. made of cellulose, whose molecular structure consists of a long chain of carbon, hydrogen, and oxygen. These fibers are typically about a micrometer (0.0001 cm) long and wrap around each other to create paper. Cellulose makes up the structure of cell walls in plants, making it a perfect ingredient for canvas materials, however, the structure of cellulose breaks down over time due to interactions with atmospheric oxygen. Oxidation, the loss of electrons by interaction with an oxidant – in this case, oxygen – is a common form of material deterioration. . In particular, it is not clear what the exact product of this reaction is, i.e. what the paper turns into when it decomposes in this way. Cellulose is broken down, through oxidation, into molecular structures commonly known as pigment cells. However, Chromophore is just a general term used to refer to the part of a molecule that can emit or absorb visible light; That’s why paper turns yellow as it ages. The exact chemical structure was not known until Conte’s work.– Courtesy of Conte et al. Further reading: Why people hate elon musk The two states of paper show markedly different light absorption bands, indicating different molecular structures present in the states. different of paper. By matching the observed absorption bands with the calculated models, they were able to determine which hydrocarbon chains were responsible for damaging the paper.Courtesy of Conte et al., Modern P2 versus Ancient Model The products of the oxidation reaction are simply the rearrangement of hydrogen, oxygen, and carbon atoms to form different chemical bonds . By sampling 15th-century manuscripts in France and Italy, Conte and his team discovered that cellulose from this period mostly decomposes into Carbon-Hydro-Oxygen chains of the aldehyde group. See pictures. With this knowledge, it is possible to devise chemical treatments to preserve paper by blocking these degradation channels. This experiment also provides a non-destructive method for determining the chemical composition of paper samples. in old paper. Writing in Physical Review Letters on April 9, 2012, they describe sampled 15th-century manuscripts in France and Italy and their subsequent finding that cellulose from this period mostly decomposes into The Carbon-Hydro-Oxygen chain belongs to the aldehyde group. Their hope is that, once the exact molecular structures are determined, the researchers will also find suitable chemical treatments that can be applied to the aging paper to prevent the change. its state. Read more: News | Top Q&A