Vulcanization — Summer 2022

Define the given terms: (i) Optimum Cure (2) Marching (3) Reversion

Compare vulcanized rubber with unvulcanized rubber.

Explain the term ‘coefficient of vulcanization’. Also describe the limitations of vulcanization temperature.

List out characteristic properties of unvulcanized rubber. Brief out any one.

Indentify reasons for less solubility of sulphur in rubber phase of latex than aqueous phase.

With labeled diagram, explain the construction and working of Moving Die Rhoemeter (MDR).

Explain the chemistry of accelerated sulphur vulcanization with suitable example.

Why sulphur vulcanization is not preferable in case of saturated rubbers?

Classify sulphur cured vulcanization system used for general purpose rubbers. Write on any one with suitable example with desired vulcanizate properties.

Explain in detail about Dithiocarbamate class accelerators.

Which major aspects decide the activity of sulfonamide accelerators?

Distinguish the vulcanization properties of Natural Rubber (NR) and Synthetic Rubber (SR).

Explain in detail about ‘Thiourea’ class accelerators.

What do you mean by mould shrinkage? How it is calculated?

Compare hot air vulcanization with steam vulcanization.

Explain the peroxide vulcanization with its reaction chemistry.

Which points are taken in account for optimization of vulcanization system?

Classify methods for assessment of state of cure. Write on any one.

With labeled diagram and reaction chemistry, explain post vulcanization network reactions.

What do you mean by cold cure?

With labeled diagram, write about rotocure curing.

Explain in detail about fluidized bed vulcanization.

Which points are taken in account during autoclave curing?

Indentify advantages of superheated steam vulcanization over saturated steam vulcanization.

Explain detail about microwave vulcanization technique.