Properties and uses of natural rubber

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Properties and uses of natural rubber: The glass transition temperature of natural rubber raw rubber is -72°C, the glue flow temperature is 130°C, the initial decomposition temperature is 200°C, and the intense decomposition temperature is 270°C. When natural rubber is vulcanized, its Tg rises and viscous flow no longer occurs. The elasticity of natural rubber is higher than that of raw rubber and vulcanized rubber whose cross-linking density is not too high. For example, in the range of 0-100℃, the resilience is between 50-85℃, its elastic modulus is only 1/3000 of steel, and its elongation can reach 1000%. After stretching to 350%, the permanent retraction deformation is only 15%. The elasticity of natural rubber is high, second only to butadiene rubber among general rubbers. The strength of natural rubber Among elastic materials, the strength of raw rubber, mixed rubber and vulcanized rubber of natural rubber is relatively high. The tensile strength of unvulcanized rubber is called Green's strength. The Green's strength of natural rubber can reach 1.4~2.5Mpa. Appropriate Green's strength is necessary for rubber processing and molding. The tear strength of natural rubber is also high, up to 98kN/m, and its wear resistance is also good. The reason why natural rubber has high mechanical strength is that it is self-reinforcing rubber. When stretched, the macromolecular chains will be oriented along the stress direction to form crystals. Electrical Properties of Natural Rubber Natural rubber is a non-polar substance and a good insulating material. When natural rubber is vulcanized, the insulation performance decreases due to the introduction of polar factors, such as sulfur, accelerators, etc. Media resistance of natural rubber Natural rubber is a non-polar substance that is soluble in non-polar solvents and non-polar oils. Natural rubber is not resistant to media such as cyclohexane, gasoline, and benzene. Unvulcanized rubber can dissolve in the above media, while vulcanized rubber swells. Natural rubber is insoluble in polar propylene and ethanol, let alone water, and is resistant to 10% hydrofluoric acid, 20% hydrochloric acid, 30% sulfuric acid, 50% sodium hydroxide, etc. Main uses of natural rubber Natural rubber is widely used in industry, agriculture, national defense, transportation, machinery manufacturing, medicine and health fields and daily life due to its strong elasticity, good insulation, plasticity, water and air barrier, tensile resistance and wear resistance, such as tires used in transportation. ； Industrial conveyor belts, drive belts, and various sealing rings ； Medical gloves, blood vessels ； Rubber shoes, raincoats, hot water bottles, etc. used in daily life are all made of rubber as the main raw material. Aircraft, cannons, tanks used in national defense, and even rockets, artificial satellites, spacecrafts, space shuttles, etc. in the field of cutting-edge science and technology all require a large number of rubber parts. This post was last edited by Warm Home on 2009-1-24 12:15 ]