Compared with other materials, plastics have the following five performance characteristics:
Light weight: Plastic is a lighter material with a relative density distribution between 0.90 and 2.2. Therefore, whether plastic can float to the water surface, especially foamed plastic, because of the micropores in it, the texture is lighter, and the relative density is only 0.01. This property allows plastics to be used in the production of products that require reduced weight.
Excellent chemical stability: Most plastics have good corrosion resistance to chemicals such as acids and alkalis. Especially the polytetrafluoroethylene (F4) commonly known as the king of plastics, its chemical stability is even better than that of gold, and it will not deteriorate if it is boiled in “aqua regia” for more than ten hours. Because F4 has excellent chemical stability, it is an ideal corrosion-resistant material, such as F4 can be used as a material for conveying corrosive and viscous liquid pipelines.
Excellent electrical insulation performance: Ordinary plastics are poor conductors of electricity, and their surface resistance and volume resistance are very large, which can be expressed in numbers up to 109-1018 ohms. The breakdown voltage is large, and the dielectric loss tangent value is small. Therefore, plastics have a wide range of applications in the electronics and machinery industries.
Poor heat conductors have the effect of noise reduction and shock absorption: Generally speaking, the thermal conductivity of plastics is relatively low, equivalent to 1/75-1/225 of steel. , better sound insulation and shock resistance. In terms of thermal insulation, 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 insulating 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.
Wide distribution of mechanical strength and high specific strength: some plastics are hard such as stone and steel, and some are soft such as paper and leather; from the perspective of mechanical properties such as hardness, tensile strength, elongation and impact strength of plastics, the distribution range Wide, there is a lot of room for choice. 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 being easy to burn, not as high in stiffness as metals, poor in aging resistance, and not heat-resistant.
Post time: Mar-19-2022
