Natural Rubber Properties
(1) Chemical properties of natural rubber Natural rubber is an unsaturated rubber that easily undergoes a vulcanization reaction (structural reaction) with a vulcanizing agent. Bromine and oxygen and ozone undergo oxidation, cracking reaction, and chlorination and reaction with halogen occur on the catalyst. With the role of acid and chemical reactions.
(2) Natural rubber has excellent comprehensive physical and mechanical properties Natural rubber has good elasticity at room temperature. This is because the natural rubber molecular chains are in an amorphous state at room temperature and the molecular chain is flexible. Its density is 0.913 g/cm, its elastic modulus is 2-4 MPa, which is about 30,000 times that of steel, and its elongation is 300 times that of steel, with a maximum of 1000%. In the 0-100 degree range, natural rubber's resilience can reach 50%-85%.
(3) Heat aging Natural rubber is a high elastic body at room temperature. Its glass transition temperature is -72 degrees. It slowly softens after being heated, starts flowing at 130-140 degrees, begins to decompose at about 200 degrees, and decomposes at 270 degrees.
(4) Medium resistance Medium refers to oils, liquid chemicals, etc. Natural rubber is not resistant to cyclohexane, gasoline, benzene and other media, insoluble in polar acetone, ethanol, etc., insoluble in water, resistant to 10% hydrofluoric acid, 20% hydrochloric acid, 30% sulfuric acid, 50% sodium hydroxide Wait. Potassium permanganate, potassium dihydrogenate, etc. that are resistant to strong acids and strong oxidation.
(5) Good processing performance Natural rubber is easy to plasticize and mix due to its high relative molecular mass, wide molecular weight distribution, and easy breakage of molecular chains, as well as the presence of a certain number of gel molecules in raw rubber. , rolling, extrusion, molding and so on.