Plastic and rubber belong to the same polymer material. They are mainly composed of carbon and hydrogen atoms. Others contain a small amount of oxygen, nitrogen, chlorine, silicon, fluorine, sulfur and other atoms. Their properties are special and their uses are special. At room temperature, the plastic is solid, very hard and cannot be stretched and deformed. The hardness of the rubber is not high, it is elastic, it can be stretched and lengthened, and the stretching can be restored to its original state. This is due to their different molecular structures. Another difference is that plastic can be recycled and reused multiple times, while rubber can not be recycled directly. It can only be processed into reclaimed rubber before it is available, so see here to understand their close relationship. Rubber is widely used because of its characteristics, first
1) The thermal conductive rubber is a poor conductor of heat, and its thermal conductivity is about 2.2~6.28 watts/m2·0K when the thickness is 25 mm. It is an excellent heat insulating material. If the rubber is made into a microporous or sponge state, The heat insulation effect will be further improved, and the thermal conductivity will be reduced to 0.4~2.0 watts. Any rubber parts that are in use may generate heat due to hysteresis loss, so care should be taken to dissipate heat.
Thermal expansion Due to the large free volume between the rubber molecular chains, the internal rotation of the segments becomes easier as the temperature rises, which makes the volume larger. The linear expansion coefficient of rubber is about 20 times that of steel. This must be considered in the design of the vulcanization model of rubber products, because the linear size of the finished rubber product will be 1.2~3.5% smaller than the model. For the same rubber, the hardness and raw rubber content of the rubber compound have a larger shrinkage rate of the rubber compound. The effect of shrinkage is inversely proportional to hardness and proportional to the gelatin content. The theoretical order of shrinkage of various rubbers is: fluororubber > silicone rubber > butyl rubber > nitrile rubber > neoprene > styrene butadiene rubber > natural rubber, which is why rubber is chosen as the pipe fittings industry. The main reason for the raw materials. In today's fast-changing rubber industry, the world rubber industry has sales of more than 250 billion US dollars, rubber products have long been an important commodity in international trade. In the world market, rubber products have formed tires as the center, focusing on industrial and construction supplies, including daily products such as rubber shoes and tapes, as well as product groups such as medical and health, culture and sports.