Summary: count celluloid first plastic products, the plastics industry from its birth, more than 120 years of history. Experienced natural polymer processing stage, the stage of synthetic resins in the 1870s, the polyolefin plastic series has become the top priority of the work, but also the emergence of multiple varieties of high-performance engineering plastics, the plastics industry tends to stabilize the growth stage, to the end of the 1970s, , the production process is more reasonable, perfect high-performance materials began to come out. Plastics with its excellent performance, in human production and life plays an immeasurable role in promoting the progress of the whole world.
Keywords: the classification of plastic synthesis deterioration and energy development prospects
Body: Since the 20th century, in the profound changes in human life, the revolution of plastic materials has played an extremely important role. Especially in the past 50 years, a variety of plastics have a wide range of uses and good performance in various fields of agriculture, packaging, light industry, textiles, construction, automotive, electrical and electronic, aerospace, defense and military industry, steel, wood, cement constitute the four basic materials of modern industry. Entering the 21st century, with the continuous penetration of information technology and other high-tech synthetic resin plastic performance to further improve, more widely, will have an increasingly important impact on the country's economic and social development and improve people's living standards.
Synthesis of a plastic
Definition of a plastic based on synthetic or natural polymer dimensions of the basic components, other fillers, and a variety of additives, under certain conditions, the plastic 1.1: Plastic Plasticizer tripping, and ultimately the same material that can maintain its shape.
1.2 Raw material: the manufacture of plastic materials is a resin, and the compounds that make up the polymer are monomers that are the basic structural units of synthetic resins. The process of development from easy to difficult has gone through the sources of monomers: animals, plants, coal, oil and gas. To date, there are four sources of monomers, oil and gas are the most important sources of raw materials for the production of plastics in industrialized countries.
1.3 Manufacturing::Division products from monomers to plastics go through polymerization and processing steps. Polymerization, the body, suspension, milk wrinkles in liquid polymerization method 4 kinds of methods. Through a certain temperature, pressure, catalyst activation polymerization into a large molecule of the monomer in the molecule, after polymerization, to get a certain shape and strength, so there is no practicality of granular polymer powder, through the extrusion, injection, calendering, cutting plastics, press (molding laminated) and other various processing into plastic products with practical value of the method, according to the use of the article before the requirements of the machining, you have to add Appropriate additives, the most commonly used plasticizers, stabilizers (heat, light stabilizers), antioxidants, etc.
The second system of classification of plastics is the classification of plastics
More complex, various methods of classification have also been crossed. The following is an introduction to the structure and properties using a simple classification.
2.1 By structure: There are two basic types of plastic polymer structure.
The first is the straight chain structure, polymer compounds with such a structure are called linear polymers. Straight-chain polymers are made of thermoplastics that can be heated to melt and recycled, common thermoplastic resins: polyethylene, polyvinyl chloride, polystyrene, polyamide, polyformaldehyde, polycarbonate, polyphenylene ether, polysulfone, rubber, etc. Advantages of the process of molding is simple, and has high mechanical energy. Its disadvantages are poor heat resistance and rigidity.
The second body structure in which the polymer has such a structure of the compound is called the body polymer compound, thermosetting plastics made by the body polymer because of the irreversible *** valence bond between the bond and the bond, and thus the formation of can not be melted and flow, and there is no new shape. The method consists of most of the condensed resin, has the advantage of high heat resistance thermosetting resin, compression easily deformed. The disadvantage is that the mechanical properties are poor. The thermosetting resins include phenolic resins, epoxy-based, amino, unsaturated polyester, and methylsilane ether resins.
2.2 percentage points, according to the use of function: 1, GE plastics: generally refers to the yield, multi-functional, good molding properties, cheap plastic. Such as polyethylene, polypropylene, phenolic resins and others. 2, engineering plastics: generally able to withstand a certain degree of external forces, with good mechanical properties and high and low temperature resistance, good foot stability, can be used as engineering structural parts of the plastic. Such as polyamide, such as polysulfone. In turn engineering plastics are divided into two categories of general engineering plastics box special engineering plastics.
Plastic applications:
Sports and fitness equipment domestic market for plastic products future demand is mainly concentrated in packaging, construction, agriculture, industry, transportation, and electronic communications; substantial growth, medical device industry, toy industry use of plastics with environmentally friendly characteristics; ABS resin has good prospects for development in building materials pipes and fittings, medical equipment and alloys **** Blends such applications. Engineering plastics will continue to be the fastest growing field. Engineering plastics is electronic information, transportation, aerospace, machinery manufacturing and other upstream industries, in the national economy occupies an important position in the development of not only can only play an auxiliary role in the country's pillar industries and modern high-tech industries, as well as to promote the transformation of traditional industries and the adjustment of product structure. In recent years, with the rapid development of China's manufacturing industry, engineering plastics applications are becoming wider and wider.
Evaluation: strong corrosion resistance, light weight, sturdy, convenient, efficient handling, raw materials are widely inexpensive, can also be used for the preparation of fuel cartridges, gas fuel, thus reducing the consumption of oil, the use of materials widely established in the forest, but the shortcomings of the plastic is the power to create a series of modified varieties of polymerized plastics dimensions are not stable, easy to aging, flammable. A variety of different additives must be added to improve service. Some plastic products are toxic ordinary plastics have antioxidant effect, difficult to corrode, intractable recycling waste plastics is very difficult, a great danger to the ecological environment. In addition, plastics made of petroleum-based products, petroleum resources are limited.
With the progress of human civilization, people began to pay attention to the natural environment and sustainable development of mankind, which highlights the environmental problems of waste plastics, white pollution "has become a global problem, and because of limited resources, such as oil, people are beginning to focus on the more efficient use of resources, these are the development of plastics, bio-degradable plastics and waste plastics, bringing challenges and opportunities. Degradation of plastics and waste plastics recycling technology research and development, and gradually reduce the harm to the ecological environment of the production of plastic materials and applications of current and future energy consumption, material costs and material use, its energy-saving advantages at the same time, there is a greater? s development space.
Direction of development: the most important thing in the future is to make full use of existing materials with a wide range of properties and processing advantages to improve its use to maintain high strength at higher temperatures, reduce the strength and deformation properties of plastics over time, and temperature dependence, enhance the learning of the combustion characteristics of plastics, the impact of aging factors. "White pollution" caused by plastic stabilization of waste plastics biodegradable polymer additives toxic, the world has invested a lot of money in R & D research and development of degradable plastics and waste plastics recycling technology. At the same time, the active development of plastic recycling technology, research and development of biodegradable plastics to meet market demand and the need for high-tech development, has become a hot spot for research, high-performance, the development of functional materials will also become a hot spot
Plastic degradation and energy
Research on biodegradable plastics
Generally, in addition to the thermal degradation of plastics photodegradable and Biodegradation in the natural environment is slower than C14-isotope tracking to check the degradation of plastic soil, the results show that the rate of plastic degradation with different environmental conditions, but usually takes 200?400 years
In order to solve this problem, the world put a lot of R & D biodegradable plastics biodegradable plastics development and application of biodegradable plastics is a class of products whose performance meets the requirements of the same in the shelf-life Performance, the use of plastics in natural environmental conditions to decompose the environmentally friendly substances, environmental protection
Plastic degradation is mainly caused by polymer bond breaking degradation of environmental conditions in the manner and degree. And its main degradation modes: hydrolytic degradation, oxidative degradation, microbial degradation,? Mechanical degradation, from a practical point of view, is generally the use of photodegradation, photobiodegradation and biodegradability, etc.
Energy saving and emission reduction, instead of using plastics and other synthetic materials, can also be in the same or similar products, with the effectiveness of traditional materials, in order to save the production of materials, processing and energy consumption; energy can be saved can be handled or equipment.
For example: It is estimated that in 1978, 150,000 tons of plastic were used to create the frame components of refrigerators and other synthetic materials used and other MCC-owned parts, saving 60% (by weight) of the thermal insulation effect of metal or glass. Without the plastic with glass or metal, the energy required 23,000,000,000,000 BTUs of energy with the consumption of two plastic parts 15,800,000,000,000 BTUs, saving 7.2 trillion BTUs of energy, equivalent to 1.2 million barrels of crude oil.
Five ends: now the pressure when the energy crisis when hidden energy saving and emission reduction has become a mainstream topic plastics in its production and use of energy-saving advantages, will certainly gain greater development and support for the research and development of biodegradable plastics in the country and white pollution and harmful waste plastics recycling technology is gradually reducing the emergence of green plastics from the essence of the just around the corner, attributable to the nature of the plastics, the prospect of unlimited! Bright!