Compared with other materials, plastics have the following performance characteristics:
1. Light weight
Plastics are lighter materials with a relative density of 0.90-2.2. Obviously, can the plastic float to the water? Especially the foamed plastic, because there are micropores in it, the texture is lighter, and the relative density is only 0.01. This property makes plastics suitable for the production of products that require less self weight.
2. Excellent chemical stability
The vast majority of plastics have good corrosion resistance to acid, alkali and other chemicals. Especially the polytetrafluoroethylene (F4), which is commonly known as the king of plastics, has better chemical stability than gold. It will not go bad even if it is boiled in "king water" for more than ten hours. F4 is an ideal corrosion-resistant material because of its excellent chemical stability. For example, F4 can be used as a material for conveying corrosive and viscous liquid pipelines.
3. Excellent electrical insulation performance
Ordinary plastics are all bad conductors of electricity. Their surface resistance and volume resistance are very large, which can reach 109-1018 ohms in digital representation. The breakdown voltage is large, and the dielectric loss angle tangent is small. Therefore, plastics are widely used in electronic industry and mechanical industry. Such as plastic insulated control cable.
4. Poor thermal conductor, with the function of noise reduction and shock absorption
Generally speaking, the thermal conductivity of plastics is relatively low, which is equivalent to the 1/75-1/225 of steel and the micropore of foamed plastics.
It contains gas and has better heat insulation, sound insulation and shock resistance. For example, the thermal conductivity of PVC is only 1 / 357 of steel and 1 / 1250 of aluminum. In terms of heat insulation capacity, single glass plastic window is 40% higher than single glass aluminum window, and double glass is 50% higher. After the combination of plastic window and hollow glass, it can be used in residential buildings, office buildings, wards and hotels. It can save heating in winter and air conditioning in summer, with obvious benefits.
5. Wide distribution of mechanical strength and high specific strength
Some plastics are hard, such as stone, steel, and some are soft, such as paper and leather. According to the mechanical properties of plastics, such as hardness, tensile strength, elongation and impact strength, they are widely distributed and have a wide range of options. Because of its small specific gravity and high strength, plastics have high specific strength. Compared with other materials, plastics also have obvious disadvantages, such as easy to burn, lower stiffness than metal, poor aging resistance, heat resistance, etc.