Question

Which of the following is used in vulcanisation of rubber?
(A) \[S{F_6}\]
(B) \[C{F_4}\]
(C) \[C{l_2}{F_2}\]
(D) \[{C_2}{F_2}\]

Answer 1

Hint: A vulcanization agent is needed in the process to form bridges between individual polymer molecules when heated. One such vulcanization agent is sulphur which provides stiffness to rubber due to its dynamic properties.

Complete step-by-step solution:
Vulcanization is a process in which heat is supplied to the polymeric chain in order to form cross-links between them. It is an important process in rubber manufacturing because rubber being an amorphous substance has very low interaction between the polymeric chains. It starts deforming on applying a little force or temperature as there is no restriction and this tendency of rubber is non-reversible.
In order to make it stable material and to stop the mobility of polymer chains, these chains are linked to each other by the method of vulcanization. To create such a cross-link, chemicals are used such as sulphur.
There are other vulcanization agents, but sulphur is dominantly used because of its reliability, flexibility and controllability of vulcanisation. Elemental sulphur is polymeric in nature i.e. sulphur itself has a chain and on applying the dynamic force, it gets distributed by the sulphur chain. The sulphur chain in between the rubber makes the polymeric chain network system more reliable and flexible.

Hence, the correct option is (A).

Note: Although sulphur is highly recommended for vulcanization, yet it has a disadvantage. It cannot resist high temperatures and that’s why we observe that sometimes rubber either melts or cannot regain its shape once stretched. Then comes other curatives such as peroxide, organic resins, etc.