Everyone should be familiar with plastics. Plastic products can be seen everywhere in our life, from children's toys to instrument containers, from computer shells to auto parts, from toothbrushes and dental jars to aircraft parts. But perhaps few people know what kind of material is called plastic? What kinds of plastics are there? When and by whom was plastic invented? How did the plastic industry develop to today's prosperity? Today, let's have a comprehensive understanding of the indispensable material in our life - plastic.
The English name "plastic" of plastic comes from the Greek "plastikos", which means "molding", "moldable" = "plastic". It is often used as an adjective, resulting in the word "plastic". The original meaning of the Chinese character "plastic" refers to "kneading characters with soil", "plasticity" is extended to "free forming", and "plastic" is also a plastic material.
In March 1926, plastics magazine of the United States defined plastics as "a material that can be molded into various shapes, which does not need cutting and chiseling like non-plastic substances." in a more strict sense, it generally refers to taking resin as the main component and adding (or not adding) plasticizers, fillers, lubricants, colorants and other additives, It is an organic polymer material that is molded into a certain shape at a certain temperature and pressure and can maintain a given shape at room temperature. Resin refers to the organic polymer (usually synthetic polymer) before processing into plastic products, which is solid or liquid at room temperature. Resin accounts for about 40% ~ 100% of the total weight of plastics. Its nature determines the basic properties of plastics, but additives also play an important role. Some plastics are basically composed of synthetic resin without or less additives, such as plexiglass, polystyrene, polycarbonate, etc. For example, the difference between plastic and resin is like bread and flour. The main component before bread processing is called flour, and the main component before plastic processing is called polymer resin.
Plastics, together with synthetic rubber and synthetic fiber, as the three major synthetic materials based on synthetic resin, have reached today's ubiquitous popularity after a hundred years, and continue to develop at an incredible speed. It is not a miracle in the world! Among them, plastics have the advantages of light weight, high strength and low price. There are more than 60 categories and more than 300 varieties. They have a wide range of applications. They have successfully replaced metals, glass and wood in many aspects, so they have an advantage in synthetic resin terminal products (more than 80%).
In 1907, phenolic plastics with coal tar as raw material was launched, marking the official beginning of the plastic era. Since then, with the popularization of electricity, the strong demand for insulating materials in the market has promoted the rapid development of plastic industry; The rise of petroleum refining industry and the development of petrochemical industry have injected fresh blood into the plastic industry. The invention of nylon stockings is like an unprecedented revolution, which has completely liberated people from the imprisonment of natural fabrics and become a milestone for the synthetic material industry, including plastics; After World War II, the resin synthesis process with petroleum products as raw materials quickly replaced the dominant position of coal chemical industry in industrial raw materials. A variety of new plastic varieties have sprung up and overwhelmed people. It is really a hundred flowers competing for beauty. It is difficult to say who is more beautiful. The popularity of plastics has brought convenience to people's life, brought a variety of colors, and also brought harm to the environment. Environmental protection issues make people hate plastics, but scientific research is endless. High technology is bound to make plastics live in harmony with nature!
The beginning of the plastic age -- the emergence of the former synthetic plastic phenolic plastic (PF)
Any commodity must have demand before it can develop, and plastics is no exception. The former fully synthetic plastic PF is related to shellac, a natural insulating material in the late 19th century. At that time, the budding power industry contained a huge market for insulating materials, but the price of shellac produced in Southeast Asia soared due to short supply. At that time, chemists began to realize that many natural resins and fibers used as coatings, adhesives and fabrics were polymers, that is, macromolecules with repeated structures, and began to look for components and methods to synthesize polymers. If anyone can invent a cheap commodity that can replace shellac, it will undoubtedly be a great success. After years of hard work, American Belgian Leo Baekeland finally became the lucky man.
Baekeland was a gifted inventor. He began to engage in chemical research in the United States in 1889 and worked for a photography supplier in New York. A few years later, he invented Velox photographic paper, which can be developed under light rather than sunlight.
In 1893, Baekeland resigned and founded nepera chemical company. Later, after two negotiations, Kodak, a photographic equipment manufacturer, bought out the patent right of Velox photographic paper at a sky high price of US $850000 (equivalent to US $15 million now).
Since 1904, Baekeland began to study the reaction between phenol and formaldehyde.
Although Bayer, a German chemist, discovered that this reaction could produce some sticky things as early as 1872, Bayer was interested in synthetic dyes and was not interested in such things. Later scientists also studied this reaction, but they couldn't find its utilization value because they couldn't accurately control the chemical reaction.
Baekeland solved the problem. He invented an experimental device called bakelizer, which can accurately adjust the heating temperature and pressure and effectively control the chemical reaction. Baekeland successfully obtained phenolic resin with this device. After molding, it obtained translucent hard plastic. This plastic is not easy to burn, no longer melts after molding, and can not be dissolved in solvents or even acids.
He named the new material bakelite with his own name, and registered the patent of bakelite on July 14, 1907. From this day on, bakelite, a former synthetic plastic, was born. Beckley filed his patent application only a day earlier than his British colleague Sir James Swinburne, otherwise the phenolic plastic might be called "swinbullet" in English. Phenolic resin is synthesized from coal tar. It is the first synthetic resin in the world. After adding sawdust to the powdered phenolic resin, it is molded under high temperature and high pressure to obtain phenolic plastic. There is no doubt that it is the first fully synthetic material made by human beings. Its birth marks that human society has officially entered the plastic age. Its invention is regarded as the alchemy of the 20th century. Its inventor Baekeland was elected president of the American Chemical Society in 1924 and called "the father of plastics" by time magazine on May 20, 1940.
On February 8, 1909, Baekeland unveiled the plastic at a meeting of the New York branch of the American Chemical Association.
In 1910, he founded general phenolic plastics and began production at a factory in New Jersey. As long as anything sells well, counterfeits will soon appear. After the previous World War, the rapid development of radio, radio and other electrical industries increased the demand for bakelite. In this way, Beckley soon had competitors, especially redmanol and condensite plastics. Edison tried to use them to make phonograph records to control the market, but failed. The emergence of fake phenolic plastics has made Baekeland use the genuine label similar to today's "Intel inside" on its products for a long time.
Patent protection expired in 1926, and a large number of similar products poured into the market. After negotiation, Baekeland merged with his opponent to have a real phenolic empire.
In 1939, Baekeland planned to wash his hands in a golden basin, but his son George Washington Baekeland had no intention of going into business. The company sold it to United carbon for us $16.5 million (equivalent to US $200 million today).
The first colorless plastic after the industrialization of phenolic plastics is urea formaldehyde plastic, which was made by Austrian chemist John in 1918. It was used as a glass substitute in Europe in the 1920s, and later commonly used to press general electrical materials and daily necessities.
Aniline formaldehyde plastic was born in 1920. The plastic has good water resistance, oil resistance and high dielectric properties, and is suitable for manufacturing insulating materials.
In the 1930s, melamine formaldehyde resin with urea as raw material appeared. The plastic made of this resin has higher hardness than urea formaldehyde plastic, better water resistance, heat resistance and arc resistance, and can be used as arc resistant insulating material. These three kinds of plastics are collectively referred to as amino plastics. They all have the advantages of hard texture, scratch resistance, colorless and translucent. Adding color materials can be made into colorful products, commonly known as electric jade. Because of their excellent electrical insulation properties, Dianyu and bakelite played a positive role in promoting the development of electrical industry and instrument manufacturing industry at that time.
Amino plastics and phenolic plastics also have a common feature - thermosetting, that is, after heating and curing, the processing process of heating, softening, cooling and hardening can not be repeated. The products can only be formed and used once, and can not be molded repeatedly. Such plastics are called thermosetting plastics, including epoxy resin and unsaturated polyester. Although this kind of plastic can not be recycled, it can still be seen everywhere in our life today because of its low price, light insulation, durability and corrosion resistance.
A milestone in the development of plastics era -- the invention of polyamide (PA)
The two world wars in the 20th century are not only the disaster of human society, but also the promoter of the development of plastic industry. After the first World War, with the gradual improvement of polymer chemistry theory and the increasing maturity of coal chemical industry, as well as the rising of petrochemical industry, the plastic industry developed rapidly. Nearly 20 varieties of more than 60 kinds of plastics commonly used today were industrialized during this period. During this period, thermoplastic, a kind of plastic variety completely different from thermosetting plastics, flourished.
Thermoplastic, as its name implies, is a plastic that can undergo multiple heating, softening, cooling and hardening processes. This kind of plastic products can be molded and reused after one-time molding and use. Therefore, it is also called renewable plastic. The waste of once formed thermoplastic is called recycled material. Recycled materials can no longer be used as food packaging, but can be widely used in industry. Most of the plastics used in our daily life belong to this kind of plastics.
From the 1930s to 1940s, the varieties and output of thermoplastic plastics increased sharply, including polystyrene (PS), polyvinyl chloride (PVC), polymethylmethacrylate (PMMA, commonly known as plexiglass), nylon, namely polyamide, PA snow, high pressure polyethylene (LDPE), fluoroplastics, acrylonitrile butadiene styrene copolymer (ABS) Silicone resin and other plastic products have been industrialized one after another, and are rapidly and widely used in Electromechanical, aviation, automobile, construction, agriculture and other fields and daily life. Among these new plastic stars, the more dazzling star is polyamide, that is, nylon born in DuPont.
