Chemistry 2001 JAMB Past Questions - Question 38: During the vulcanization of rubber, sulphur is added to

Correct Answer

C

Explanation

During the vulcanization of rubber, sulfur is added to improve the properties of the rubber. Vulcanization is a chemical process that involves the cross-linking of polymer chains in rubber, typically natural rubber or related polymers. The addition of sulfur to rubber and the subsequent vulcanization process result in the formation of cross-links, which are chemical bonds between the polymer chains. This process enhances the mechanical properties, durability, and elasticity of the rubber.

Here are some key aspects of vulcanization with sulfur:

1. **Cross-linking:** Sulfur forms bridges (cross-links) between the polymer chains, creating a three-dimensional network structure. This cross-linking imparts strength and resilience to the rubber, improving its overall performance.

2. **Increased Elasticity:** Vulcanization increases the elasticity of rubber, making it more flexible and resistant to deformation. This is crucial for applications where rubber needs to stretch or compress without losing its shape.

3. **Improved Heat Resistance:** Vulcanized rubber exhibits better heat resistance compared to untreated rubber. This is particularly important for applications where rubber is exposed to high temperatures, such as in the automotive industry.

4. **Enhanced Chemical Resistance:** Vulcanization improves the resistance of rubber to various chemicals, making it more suitable for use in diverse environments.

5. **Reduced Tackiness:** Vulcanization reduces the tackiness of rubber, making it less likely to stick to surfaces. This property is important for the usability and handling of rubber products.

The vulcanization process is typically carried out by heating the rubber compound containing sulfur. The specific conditions, such as temperature and time, can be adjusted to achieve the desired properties in the vulcanized rubber. Different formulations and curing processes may be used depending on the intended application of the rubber product.