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Answer:
Vulcanization is the chemical process of converting natural polymer into more durable materials through mixing with some chemicals such as: Sulphur, hydrogen sulphide, or other equivalent curatives or accelerators in other to improve the polymer properties
Vulcanization of natural rubeer is the process of mixing natural rubber with some other chemicals like Sulphur, and hydrogen sulphide in other to improve its properties such as the strength. This is usually done to improve the mechanical properties by crosslinking of the polymer; thereby, preventing intermolecular movement of rubber spring. the reaction of natural rubber with sulphur is show in Figure 2 below.
Figure 2. Vulcanized rubber production reaction.
Comparison of natural rubber with vulcanized rubber
Natural rubber. | Vulcanized rubber. |
---|---|
Low tensile strength and brittle when cold. | High tensile strength of about 2000 kg/cm2. |
Poor material for high elasticity applications. | Good for high elasticity applications. |
Exhibits good strength at temperature ranges of 10 to 60oC. | Exhibits good strength at temperature ranges of -40 to 100oC. |
It is soft and sticky | It is comparatively hard and non-sticky. |
Deforms at high tension | Although it temporarily deforms at high tension, but it regains back the shape when the tension load is removed. |
Low abrasion resistance | High abrasion resistance |
It has high water absorption | It has low water absorption. |
It is susceptible to chemical attack | It shows resistance to chemical attack. |
It is not resistant to oxidation | It is resistant to oxidation. |
Soluble in solvent like ether, carbon disulphide, petrol, turpentine and carbon tetrachloride | Insoluble in most solvent like ether, carbon disulphide, petrol, turpentine and carbon tetrachloride |