Question

iii.
Explain vulcanisation of rubber.
Which vulcanizing agents are used
for the following synthetic rubber.
Neoprene b. Buna-N
​

Answer 1

Answer:

The material used for the vulcanisation of rubber is sulphur.

The reasons why the rubber is vulcanised are as follows:

i) It is soft and sticky and becomes more so at high temperature and brittle at low temperature. That is why, it is used at low-temperature range (280−330) K, where its elasticity is maintained.

ii) It is attacked by oxygen and other oxidising agents.

iii) It has a high water absorption capacity, low tensile strength and low resistance to abrasion.

iv) It is reactive to organic solvents.

Therefore, natural rubber is vulcanised by heating it with about (3−5%) sulphur at (373−415) K.

Answer 2

Question :

Explain vulcanisation of rubber. Which vuleanizing agents are used for the following synthetic rubber.

1. Neoprene

2. Buna-N

Answer:

The process by which a network of. cross links is introduced into an elastómer is called vulcanization.

Vulcanization enhances the properties of natural rubber like tensile strength, stiffness, elasticity, toughness etc. Sulphur forms cross links between polyisoprene chains which results in improved properties of rubber.

• (1) For neoprene vulcanizing agent is MgO.
• (2) For Buna-N vulcanizing agent is sulphur.