Three kinds of synthetic materials are indispensable in our daily life. Specifically, plastic is a material that takes natural or synthetic resin as the main component and adds various additives, and can be molded into a certain shape under certain conditions such as temperature and pressure, and keeps the shape unchanged at room temperature.
The performance features are as follows
1. Lightweight
2. Excellent chemical stability
3. Excellent electrical insulation performance
4. Thermal poor conductor has the function of noise elimination and shock absorption.
5. The mechanical strength is widely distributed and the specific strength is high.
Please refer to the following links for details.
baike.baidu/...Qviq#3
Question 2: What are the items of plastic products? According to the different use characteristics of famous plastics, plastics are usually divided into general plastics, engineering plastics and special plastics.
Plastics can be easily molded into different shapes according to their own characteristics. Widely used in all walks of life and all aspects of people's lives.
Question 3: What kinds of plastics are there? Plastic is a widely used synthetic polymer material, and plastic products can be found everywhere in our daily life. From the toiletries used after getting up, the tableware used for breakfast, to the stationery used for work and study, the cushion mattress used for rest, the casing of TV, washing machine and computer, and the lights of various shapes that bring us light at night. ...
With its excellent performance, plastics have gradually replaced many materials and utensils that have been used for decades and hundreds of years, and become an indispensable assistant in people's lives. Plastic combines the hardness of metal, the lightness of wood, the transparency of glass, the corrosion resistance of ceramics and the elasticity and toughness of rubber. Therefore, in addition to daily necessities, plastics are more widely used in aerospace, medical equipment, petrochemical, machinery manufacturing, national defense, construction and other industries.
I. Classification of plastics
There are many kinds of plastics, so far there are about 300 kinds of plastics put into production in the world. There are many ways to classify plastics, and there are two commonly used methods:
1, according to the different properties of plastics after heating, it can be divided into thermoplastic and thermosetting plastics.
The molecular structure of thermoplastics is linear, which softens or melts when heated, can be shaped into a certain shape, and then hardens after cooling. It becomes soft when heated to a certain extent, and becomes hard after cooling. This process can be repeated many times. Such as polyvinyl chloride, polyethylene, polystyrene, etc. Thermoplastic molding process is relatively simple, can be produced continuously, and has quite high mechanical strength, so it develops rapidly.
The molecular structure of thermosetting plastics is a kind of bulk structure, which can be softened by heating and shaped into a certain shape. However, after heating to a certain extent or adding a small amount of curing agent, it will harden and set, and will not soften and deform after reheating. Thermosetting plastics, such as phenolic plastics, amino plastics, epoxy resins, etc. Can't be recycled after processing and molding. Thermosetting plastics are complicated in molding process and difficult to produce continuously, but they are good in heat resistance, difficult to deform and relatively low in price.
2. According to the different uses of plastics, they can be divided into general plastics and engineering plastics.
General plastics refer to plastics with large output, low price and wide application range, mainly including polyolefin, polyvinyl chloride, polystyrene, phenolic plastics and aminoplastics. Many products used in people's daily life are made of these general plastics.
Engineering plastics can be used as engineering structural materials instead of metals to manufacture machine parts. Such as polyamide, polycarbonate, polyoxymethylene, ABS resin, polytetrafluoroethylene, polyester, polysulfone, polyimide and the like. Engineering plastics have the characteristics of low density, high chemical stability, good mechanical properties, excellent electrical insulation and easy processing and molding. , widely used in automobiles, electrical appliances, chemicals, machinery, instrumentation and other industries, as well as aerospace, rockets, missiles and so on.
Second, the composition of plastic
The plastic we usually use is not a pure substance, it is made of many materials. Polymer (or synthetic resin) is the main component of plastic. In addition, in order to improve the properties of plastics, various auxiliary materials, such as fillers, plasticizers, lubricants, stabilizers, colorants, etc. , must be added to the polymer to become a plastic with good performance.
1, synthetic resin
Synthetic resin is the most important component in plastics, and its content in plastics is generally 40% ~ 100%. Because of its large content and the nature of resin often determines the nature of plastic, people often regard resin as synonymous with plastic. For example, PVC resin and PVC plastic, phenolic resin and phenolic plastic are confused. In fact, resin and plastic are two different concepts. Resin is a kind of raw material polymer, which is not only used to make plastics, but also used as raw material for coatings, adhesives and synthetic fibers. Except a few plastics contain 100% resin, most plastics need to add other substances besides the main component resin.
Step 2 pack
Fillers, also called fillers, can improve the strength and heat resistance of plastics and reduce costs. For example, adding wood flour to phenolic resin can greatly reduce the cost, make phenolic plastic one of the cheapest plastics, and significantly improve the mechanical strength. Fillers can be divided into two categories: organic fillers, such as wood flour, rags, paper and various fabric fibers; Inorganic fillers, such as glass fiber, diatomite, asbestos and carbon black.
3. Plasticizer
Plasticizers can increase the plasticity and softness of plastics, reduce brittleness, and make plastics easy to process and shape. Plasticizer is usually miscible with resin, non-toxic, tasteless and light-sensitive. & gt
Question 4: What plastic inventions are common plastic products in life and can be called masterpieces of human beings in the 20th century? Plastic has undoubtedly become an indispensable and important raw material in modern civilized society. At present, plastics have been widely used in aviation, aerospace, communication engineering, computer, military, agriculture, light industry, food industry and other industries. Plastic, literally speaking, is a moldable material, that is, plastic material. Nowadays, plastic is a proper term for a kind of materials that are cast, extruded, blown or injected into molds by resin at a certain temperature and pressure. During the 65438+60s, due to the shortage of ivory in the United States, there was a lack of raw materials for making billiards. The earliest artificial plastic celluloid was patented in 1869. Although celluloid is the earliest artificial plastic, it is an artificial plastic, not a synthetic plastic. The first synthetic plastic was made of phenolic resin by pressing with a heating mold. It was made by Backlander, an American Belgian chemist of 19 10 in the early 20th century. Backlander used sawdust to heat and pressurize phenolic resin to make various products, which were named bakelite after his surname, and we called it bakelite. After the First World War, the radio, radio and other electrical appliances industries developed rapidly, increasing the demand for bakelite, which has been used ever since. In the chemical industry, instruments that don't need acid to work were once made of special steel, which was very expensive. It is much cheaper to replace them with alkali-resistant bakelite. But bakelite is not alkali-tolerant. It is a good material for making buttons and chess pieces. Some parts of tractors and cars are also made of it. Austrian chemist John made urea-formaldehyde resin. The plastic made of it is colorless, light-resistant, high in hardness, high in strength, non-flammable and light-permeable, also called electric jade. In the 1920s, it was used as a glass substitute in Europe. In 1930s, melamine formaldehyde resin appeared again, which was made of urea. Melamine formaldehyde resin can be used to make arc-resistant materials, which are fire-resistant, waterproof and oil-resistant. Since then, plastics such as polyethylene, polyvinyl chloride, polystyrene and plexiglass have appeared one after another. I have to say that bakelite opened the door. The 20th century is the century of plastics. Looking back on the 100-year history of plastics and looking forward to the 2 1 century, with the emergence and development of high-speed computers, information and network technologies, new energy, aerospace technology, life sciences and other cutting-edge technologies, human society will surely undergo further changes, and the space for human activities in the sky and the earth will also be further expanded, while nano-plastics, optical fibers, conductive plastics, magnetic plastics, memory plastics, etc. will also be further developed. It is believed that the human history of Paleolithic Age, Neolithic Age, Pottery Age, Bronze Age and Iron Age has accelerated the improvement of civilization because of plastics. Although people have been exclaiming the arrival of the plastic age in the past century, perhaps the new century is the real arrival of the plastic age, and the past century is only a prelude to the plastic age.
Question 5: Types of plastic products The types of plastic products are as follows:
1, PET: polyethylene terephthalate
2.HDPE: high density polyethylene
3.PVC: polyvinyl chloride
4. Low density polyethylene 5. Polypropylene
6.polystyrene
7. Polycarbonate
8.polyamide
9.ABS resin
10, * * * mixture (XX-XX alloy)
Question 6: What are the common plastic products? We can see plastic products everywhere, such as plastic pots, barrels, lunch boxes, plastic pipes, plastic films and so on.
Question 7: What plastic products are there in life? 10 plastic bag.
Packaging bag.
Plastic chairs.
Disposable plastic cups.
Cover or seal of McDonald's, KFC or other beverage stores.
Mineral water bottle.
Mobile phone protective case.
Plastic washbasin. Toothbrush handle.
Plastic wastepaper basket.
Plastic film for packaging books.
Plastic briefcase.
Umbrella. Chuhe adhesive tape