Because of its excellent performance and easy processing, plastic materials have the largest output and the most widely used polymer materials among the three major synthetic materials of plastics, rubber and synthetic fibers. At present, the application field of plastic materials is still being further expanded, which has already involved all aspects of the national economy and people's lives.
　　Compared with other materials, plastic has the following performance characteristics:

1. Light weight
         Plastic is a lighter material with a relative density of 0.90-2.2. Obviously, can plastics float on the water? Especially foamed plastics, because of the micropores inside, the texture is lighter, and the relative density is only 0.01. This feature allows plastics to be used in the production of products that require lightening of their own weight.

2. Excellent chemical stability
         Most plastics have good corrosion resistance to chemicals such as acids and alkalis. In particular, polytetrafluoroethylene (F4), commonly known as the king of plastics, is more chemically stable than gold, and it will not deteriorate even if it is boiled in "aqua regia" for ten hours. Because F4 has excellent chemical stability, it is an ideal corrosion-resistant material. For example, F4 can be used as a material for conveying corrosive and viscous liquid pipelines.

3. Excellent electrical insulation properties
         Ordinary plastics are poor conductors of electricity, and their surface resistance and volume resistance are very large, which can reach 109 to 1018 ohms in numbers. The breakdown voltage is large, and the dielectric loss tangent value is small. Therefore, plastics have a wide range of applications in the electronics industry and machinery industry. Such as plastic insulated control cables.

4. Poor thermal conductor, with noise reduction and shock absorption effect
         Generally speaking, the thermal conductivity of plastic is relatively low, equivalent to 1/75—1/225 of steel, and the micropores of foam plastic.
         It contains gas, which has better heat insulation, sound insulation and shock resistance. For example, the thermal conductivity of polyvinyl chloride (PVC) is only 1/357 of steel and 1/1250 of aluminum. In terms of thermal insulation capacity, single-glass plastic windows are 40% higher than single-glass aluminum windows, and double-glass windows are 50% higher. After the plastic window is combined with the hollow glass, it can be used in residences, office buildings, wards, and hotels, saving heating in winter and saving air-conditioning expenses in summer, and the benefits are very obvious.

5. Wide distribution of mechanical strength and higher specific strength
        　　Some plastics are as hard as stone and steel, and some are soft as paper and leather. From the perspective of mechanical properties such as hardness, tensile strength, elongation, and impact strength of plastics, they have a wide distribution range and have a lot of options for use. Due to the small specific gravity and high strength of plastic, it has a high specific strength. Compared with other materials, plastics also have obvious shortcomings, such as flammability, higher stiffness than metals, poor aging resistance, and heat resistance.

development trend
        　　The development direction of plastics can be summarized in two aspects. The first is to improve performance, that is, to modify existing varieties in various ways to improve their comprehensive performance; the second is to develop functions, that is, to develop polymer materials with optical, electrical, magnetic and other physical functions, so that plastics can have Photoelectric effect, pyroelectric effect, piezoelectric effect, etc.
        　　Judging from the current development speed of the world's plastics industry, Germany and Sweden rank first, followed by Japan and some European countries, and the United States is slower. Foreign plastic packaging presents the following development trends: Copolymer composite packaging film
        　　At present, some countries in Europe and the United States have invested heavily in the development of non-polar and polar ethylene copolymers, which will greatly improve the stretch and co-extrusion properties of the plastic film, and improve the transparency, sealing strength, stress resistance, crack resistance, and stability. , Improve the rheological properties of molecular weight cloth and extrusion.