Polystyrene is used in making Petri dishes and various other laboratory containers.

(a) What type of polymer is polystyrene?

(b) Is this an addition polymer or a condensation polymer?

(c) Suggest which monomer might be used to synthesize this polymer and how the polymerization might be accomplished.

In this process, the molecules of the same or different monomers simply add to one another in repetition leading to the formation of a polymer in which the molecular formula of the repeat unit is the same as that of the monomer.

In this process, a large number of monomer molecules combine together usually with the loss of simple molecules like water, alcohol, ammonia, carbon dioxide, hydrogen chloride etc., to form a polymer in which the molecular formula of the repeat unit is not the same as that of the monomer.

(a) Thermoplastic polymers are those which can be melted over and over again without any change. Polystyrene is a type of thermoplastic polymer.

(b) Addition polymer normally occurs among molecules containing double bonds. The monomer for polystyrene synthesis is styrene (C₆H₅CH=CH₂) which contains a double bond. Hence, polystyrene synthesis is a type of addition polymer.

(c) The monomer used for the synthesis of polystyrene is styrene (C₆H₅CH=CH₂) . Styrene in presence of peroxides undergo addition polymerization to give polystyrene.

styrene polystyrene

synthesis of polystyrene from styrene