The main use of natural rubber has a series of physical and chemical properties, especially its excellent resilience, insulation, water insulation and plasticity characteristics, and, after appropriate treatment also has oil resistance, acid resistance, alkali resistance, heat resistance, cold resistance, pressure resistance, abrasion resistance, and other valuable properties, so there is a wide range of uses. For example, rainboots, warm water bags, elastic bands used in daily life; surgeon's gloves, blood tubes, condoms used in the medical and health care industry; a variety of tires used in transportation; conveyor belts, conveyor belts, acid-resistant and alkali-resistant gloves used in industry; agricultural use of drainage and irrigation hoses, ammonia bags; meteorological measurements of the use of the sounding balloon; scientific testing of the sealing, shock-proof equipment; the national defense of the use of the aircraft, Tanks, artillery, gas masks used in national defense; even rockets, artificial Earth satellites and spacecraft and other highly sophisticated science and technology products are inseparable from natural rubber. The advantages and disadvantages of natural rubber is not fixed, in different occasions to apply its different characteristics, the application of the occasion is not right, some of the advantages will become disadvantages.
The characteristics of natural rubber:
1, high elasticity, according to the different formulations, the elasticity of up to 80%.
2, high elongation, up to 1000% or more.
3, low modulus of elasticity and shear modulus, much lower than some rigid substances such as steel and so on
4, because natural rubber is crystalline rubber, strength is very high in rubber, unreinforced natural rubber tensile strength of 25~30MPa, reinforced natural rubber can reach 32MPa. but much lower than steel.
5, cold resistance is better, the glass transition temperature of -72 ℃.
6, low density, the density of raw rubber is less than 1g/cm^3.
7, there is a side methyl group on the main chain, easy to rearrangement, heat resistance is not good, the long-term use of the temperature is not more than 70 ℃
8, the main chain contains a double bond, easy to be attacked, not resistant to aging, and also can be modified to the double bond, such as chlorination, epoxidation, to improve the heat and oil resistance.
9, oil resistance, chemical resistance (except alkali) performance is not good, in the concentrated hydrochloric acid double bond will be added with HCl to produce a protective film on the surface, to prevent further reaction.