Plastic bag is a bag made of plastic (commonly used plastics are polypropylene, polyester, nylon, etc.) as the main raw materials. It is an essential item in People's Daily life and is often used to hold other items. Because of its cheap, very light weight, large capacity, convenient storage advantages are widely used.

Cybertron discovered that nitrocellulose was malleable, and that things made from it were impermeable to water. He was very interested in making some beautiful rice bowls, cups, bottles and teapots from it. He was so impressed with his work that he wrote a letter to his friend, the famous scientist Faraday, about his unexpected gain. But Faraday didn't care until a photographer showed up. Photographer Alexander Parks has many hobbies, and photography is one of them. In the 19th century, people could not buy ready-made photographic film and chemicals as they do today. They often had to make what they needed. So every photographer must also be a chemist.

The "ancestor" of this amazing material is the most abundant cellulose in plants.

In 1845, living in the northwestern city of Basel, Switzerland, a chemist Cybertan did an experiment at home, accidentally came across the table of concentrated sulfuric acid and concentrated nitric acid, he quickly picked up his wife's cloth apron to wipe the mixed acid on the table. In a hurry, he hung the apron over the stove to dry, but it burst into flames with a "pop" and instantly turned to ashes. Cybertron returned to the lab with this "great discovery" and repeated "accidents". After many tests, Cybertron finally found the reason: the main component of the original cloth apron is cellulose, which contacts with a mixture of concentrated nitric acid and concentrated sulfuric acid to produce nitrocellulose lipid, which is later widely used nitrocellulose.

One of the materials used in the photography is "colloidum", a solution of "nitrocotton", a cellulose nitrate solution in alcohol and ether. It was used to glue light-sensitive chemicals to glass to make the equivalent of today's photographic film.

In the 1850s, Parks looked at different ways of dealing with gum cotton. One day he tried to mix collodion with camphor. To his surprise, the result was a hard material that could be bent. Parks called the substance "paxine," and it was the first plastic.

Parks made everything from Pacsin: combs, pens, buttons, and jewelry prints. However, Parks had little business sense and lost money on his business ventures. In the 20th century, people began to find new uses for plastic. Almost everything in a home can be made from some kind of plastic.

It was left to other inventors to develop and profit from Parks's work. John Wesley Hayat, a printer from New York, saw an opportunity in 1868, when a company that made billiards balls complained of a shortage of ivory. Hayat improved the manufacturing process and gave Paxine a new name, celluloid. He got a ready market from billiard ball manufacturers and was soon making a wide variety of products out of plastic.

Early plastics were prone to catch fire, which limited the range of products made with it. The first plastic that successfully withstood high temperatures was "beckelet." Leo Baekeland obtained the patent in 1909.

Bakelite was first synthesized in 1909 by Baekland in the United States. In the 1930s, nylon was introduced, described as "a fiber made of coal, air, and water, thinner than spider silk, stronger than steel, and better than silk." Their emergence laid the foundation for the invention and production of various plastics since then. Due to the development of the petrochemical industry during the Second World War, the raw material of plastic was replaced by coal with oil, and the plastic manufacturing industry also developed rapidly.

Plastic is a very light substance, which can be softened by heating it at a very low temperature, and can be made into all kinds of shapes at will. Plastic products are bright color, light weight, not afraid of falling, economic and durable, its advent not only brings a lot of convenience to people's life, but also greatly promotes the development of industry.