Books will turn yellow after being stored for a long time

Generally, the yellowing of paper is due to oxidation. If you can avoid oxidation as much as possible, you can also avoid the yellowing of the paper.

As long as you can ensure the following three points, the yellowing of the paper can basically be avoided.

These three points are to reduce contact with air, reduce contact with moisture, and reduce contact with sunlight.

Contact with air cannot be avoided by ordinary people, but contact with moisture and sunlight can be avoided as much as possible. If you don't use certain books often, you can try putting them in a plastic bag and sealing them so that you can take them out when you use them.

Generally, the storage period of paper should not exceed one year, even if the condition of storing the paper is good, the paper will be discolored and deteriorated if it is stored for too long. If the paper is stored for two years, the coated paper will turn yellow and depowder; newsprint turns yellow and brittle; Discoloration and reduced strength of the wrapping paper; Yellow cardboard and containerboard can become moldy and deteriorate, and so on.

If you buy a yellow book, you won't be yellow.

Personal opinion: Cover the book with a transparent veil or something else, which looks good and avoids dusting or something.

The raw materials for papermaking are wood, grass, hemp, reeds, bamboo, bagasse and rags. Papermakers break up the raw materials, and after steaming, they make yellow pulp, and people have to bleach the pulp with bleaching powder or chlorine gas to make white paper.

The paper used to print newspapers is relatively rough and easily absorbs moisture from the air. The sunlight and the various gases in the air ruined the results of the bleaching, and the newspaper turned yellow again.

Both paper and ambient temperature are relative.

The yellowing of books has a lot to do with the acidification of the paper.

Humidity combined with high levels of sulphur dioxide and nitrogen oxides in the air is a major factor.

Because moisture is easy to make the paper acidic hydrolysis.

Yellowing is a precursor to acidic hydrolysis.

In addition, excessive dust can also easily affect the yellowing of the book.

1. There is an idiom called Shelving the Pavilion, which originally meant to put the book in a high place. The book should be placed in a high place to avoid absorbing moisture from the ground, which can cause mold and mildew. You can see this by looking at the books in the library.

2. When reading a book, you should clean your hands again and then read it, which will reduce the sweat or bacteria on your hands attached to the page, which will cause the page to be damaged by mold if you do not read it for a long time. Sweat sticks to the pages of a book, and it can easily change color.

3. The place where the book is stored should be kept ventilated and dry, and the indoor air is dry, so that the pages will not absorb the moisture in the air, so that the book will turn yellow and discolored, and mold spots will appear, because the book is originally bound from a page of paper, and the paper is very easy to absorb water.

4. When the weather is fine, try to let the book shine into the sun, which can not only evaporate the enzyme moisture in the pages, but also the ultraviolet rays inside.

It can also sterilize. This method is used by many people, and sunlight is the best desiccant for sterilization.

5. Around the bookshelf of the book, place a few packets of desiccant and anti-mold tablets, which can not only prevent mildew and moth, but also absorb water vapor in the air.

It plays a role in protecting the collection.

6. In your spare time, use a dry rag or feather duster to clean up the dust on the surface of the book, on the one hand, the moldy book is to absorb too much water vapor, the pages are rotten, on the other hand, it is caused by the dust in the air with bacteria falling on it, so occasional dust removal is essential.

If you want to keep the book from yellowing, you should put it in a cool and dry place, and you can take out more books to dry when the sun is shining, so that it is not easy to yellow and not easy to grow insects.

How do I keep my book from yellowing? Wrap the book in the skin and make it with plastic, so that the book will not turn yellow.

①.Be acid-proof. In acidic conditions, books are more susceptible to oxidation.

Be moisture-proof. In humid conditions, the surface is prone to absorb components in the air such as carbon dioxide, forming an electrolyte layer, which usually forms the galvanic cell principle, which accelerates the oxidation process.

Therefore, moisture protection is a must. You can buy some moisture-proof agents when storing them and replace them regularly. Under dry conditions, books oxidize very slowly.

Moisture-proof agent).Books should be kept away from light. Under light conditions, paper products are prone to yellowing and brittleness.

If conditions permit, the books can be sealed completely and isolated from the air after being packed by a plastic sealing machine, which can greatly reduce the problem of oxidation.

Books should be ventilated and dried to avoid being exposed to water vapor in the air, which can turn yellow and cause mold spots. For precious books, you can often blow it with a hair dryer, which can repel moisture and mildew and prevent the paper from yellowing.

Generally, the yellowing of book paper is due to oxidation. If you can avoid oxidation as much as possible, you can also avoid the yellowing of the paper.

01 Paper is usually made of wood, and the main components of natural wood are cellulose and lignin. However, lignin and some cellulose are very susceptible to oxidation – they absorb additional oxygen molecules, causing changes in the original molecular structure, especially breaking the bonds in lignin that hold the molecular units together, and forming a molecular region called a "penny chromophore". After the lignin is oxidized, we will see yellow or brown.

Paper is widely used in books, magazines, calligraphy and paintings, stamps, banknotes, contracts, treaties, etc., and is one of the important carriers of recording and disseminating culture, which is closely related to people's lives. However, when you look at the books you used a few years ago, you will be surprised to find that all the paper of the books has turned yellow, and some of the papers have even become "weak", and they will be damaged after a few more turns.

When the finished paper reaches the user, it must go through the processes of cooking, bleaching, dechlorination, whitening, copying, storage in the warehouse, transportation and store display. The raw material of paper is wood, and wood contains a certain percentage of lignin. Lignin is composed of phenylpropane building blocks, and when bleached, lignin remains in the fibers although it becomes a colorless alkylphenol state due to oxidation and hydrolysis, and these alkylphenols become quinone structures through oxidation such as sunlight exposure, which has the ability to absorb visible light and exhibit hues from yellow to brown.

Of course, the yellowing of the paper is also inseparable from the exposure of light, and the yellowing rate of the paper will be accelerated under the exposure to the sun. Certain substances in the air will form strong oxidants under ultraviolet irradiation, which will oxidize and degrade cellulose, hemicellulose and lignin, and cause the paper to age. In addition, ultraviolet light can directly cause the cleavage of C-C and C-O bonds, resulting in a decrease in the polymerization of cellulose, hemicellulose and lignin.

At the same time, the infrared rays in the light will heat the paper, so that the temperature of the paper will increase, the internal reaction speed will be accelerated, and the phenomenon of yellowing, brittleness, and degradation of the edge part of the paper will be accelerated. The yellowing and brittleness of paper is very detrimental to the preservation of books and important documents. Studies have shown that to inhibit the yellowing of paper, lignin must first be removed during the papermaking process.

In fact, as long as some chemicals are added when crushing wood, the lignin can be removed, so as to make paper that is not easy to yellow. However, a quarter of the wood is wasted in this way to make paper. In addition, researchers have also experimentally compared various methods to prevent yellowing of paper, and found that a substance called polyethylene glycol is effective in inhibiting yellowing.

Newspapers coated with polyethylene glycol do not turn yellow even after prolonged exposure to light. Applying different amounts of polyethylene glycol to thick, unprinted newsprint, and then irradiating it with an extra strong artificial light equivalent to two days of direct sunlight, the results showed that the more polyethylene glycol was coated, the lower the degree of yellowing.

The causes of yellowing of paper are complex, considering the raw material composition of the paper and its surrounding environmental influence, it is best to store the collected books and newspapers in a dry and dark place.

1. Some books will turn yellow after a long time, mainly because the paper is oxidized, because the book is bound by paper with printed words, and the raw material of paper is wood, and the lignin in the wood will turn yellow after the oxygen in the air reacts. Daily books should be kept moisture-proof, moisture is very bad for books, and it should be protected from light.

2. Books must be best moisture-proof in the process of preservation, because moisture is very unfavorable to books, it will accelerate the aging of the paper, and corrosive effect on the current position of the paper, so it must be kept in a dry and ventilated place. Books should also be kept away from light, light is also harmful to books, and direct sunlight should be avoided.