Question

Which of the following processes can be used to prepare polystyrene $ ? $
(A) Anionic
(B) Cationic
(C) Free radicals
(D) Ziegler-Natta

Answer 1

Hint :Polystyrene is a polymer of styrene. It is a synthetic aromatic hydrocarbon. Polystyrene is made in a process known as suspension polymerization. Polystyrene is prepared by free radical addition polymerization of styrene in the presence of benzoyl peroxide as a catalyst.

Complete Step By Step Answer:
The simplest way to catalyze the polymerization reaction that leads to an additional polymer is to add a source of a free radical to the monomer.
Anionic Polymerization: Addition polymers can also be made by chain reactions that proceed through intermediates that carry either a negative or positive charge. When the chain reaction is initiated and carried by negatively charged intermediates, the reaction is known as anionic polymerization. Like free-radical polymerizations, these chain reactions take place via chain-initiation, chain-propagation, and chain-termination steps.
Cationic Polymerization: The cationic polymerization reaction is initiated by adding a strong acid to an alkene to form a carbocation. The ion produced in this reaction adds monomers to produce a growing polymer chain. The chain reaction is terminated when the carbonium ion reacts with water that contaminates the solvent in which the polymerization is run.
Ziegler-Natta catalysts produce a linear polymer, which is rigid, with a higher density and a higher tensile strength. Ziegler-Natta catalysts provide an isotactic polypropylene, which is harder, tougher, and more crystalline.
Hence the correct options are A, B, C and D.

Note :
In suspension polymerization, after styrene is produced by combining ethylene and benzene, it is merged with water and a mucilaginous substance to form droplets of polystyrene. Polystyrene is non-planar in nature and its general chemical formula is $ {\left( {{C_8}{H_8}} \right)_n} $ . For example, polypropylene produced by free-radical reactions is a soft, rubbery, atactic polymer with no commercial value.