塑料特性.（Plastic properties.）.doc

塑料特性.（Plastic properties.） Lightweight plastic is a lighter material with a relative density of 0.90 to 2.2. Obviously, can plastic float to the surface? Especially foamed plastics, because there are micropores, the texture is lighter, the relative density is only 0.01. This feature enables plastics to be used to reduce the production of self-heavy products. 2. The excellent chemical stability of most plastics has good corrosion resistance to acids, alkali and other chemicals. In particular, polytetrafluoroethylene (F4), commonly known as plastic wang, is more chemically stable than gold, and boiled in wang shui for more than a dozen hours. Because F4 has excellent chemical stability, it is an ideal corrosion resistant material. F4 can be used as a material for conveying corrosive and viscous liquid pipes. 3. The excellent electrical insulation performance of ordinary plastic is the poor conductor of electricity, its surface resistance and volume resistance are very large, with the number of 109, 1018 ohms. The breakdown voltage is large, and the tangent value of dielectric loss is very small. Therefore, plastics are widely used in electronic industry and mechanical industry. A plastic insulated control cable. 4. A poor conductor of heat, with noise elimination and damping effect Generally speaking, the thermal conductivity of the plastic is relatively low, quite steel 1/75-1/225, the microporous foam contains gas, its better heat insulation, sound insulation, shockproof sex. The thermal conductivity of polyvinyl chloride (PVC) is only 1/357 of steel and 1/1250 of aluminum. In thermal insulation capacity, single glass window is 40% higher than single glass window and 50% of double glass. After combining the plastic form with the hollow glass, in the residence, office building, the ward, the hotel USES, the winter saves heating, the summer saves air conditioning expenses, the advantage is very obvious. 5. The distribution of mechanical strength is wide and higher tha