Low density: The low density of plastics is of great significance for reducing the weight of mechanical equipment and energy saving, especially for vehicles, ships, aircrafts, and spacecraft.
High specific strength and specific stiffness: The absolute strength of plastic is not as high as that of metal, but the density of plastic is small, so the specific strength (σb/ρ) and specific stiffness (E/ρ) are quite high. In particular, reinforced plastics made of various high-strength fibrous, flake and powdered metal or non-metal fillers have higher specific strength and specific rigidity than metals.
Good chemical stability: Most plastics have good resistance to acid, alkali, salt, water and gas. Under normal conditions, they do not chemically react with these substances.
Good electrical insulation, heat insulation and sound insulation performance.
Good wear resistance and self-lubrication: plastic has a small friction coefficient, good wear resistance, and good self-lubrication. In addition, it has high specific strength and low transmission noise. It can be rubbed in liquid medium, semi-dry or even dry Work effectively under conditions. It can be made into machine parts such as bearings, gears, cams and pulleys, and is very suitable for occasions where the speed is not high and the load is not large.