Chapter 21, Problem 70E

(a)

Interpretation Introduction

Interpretation: The term ‘polystyrene’ needs to be defined and the reason of forming stronger polystyrene on addition of catalyst to form syndiotactic polystyrene needs to be explained.

Concept Introduction : Syndiotactic polystyrene (SPS) is polymer of a semicrystalline type and prepared from monomer styrene by use of a single-site catalyst like metallocene.

(b)

Interpretation Introduction

Interpretation: The reason of formation of stronger polymer on addition of 1,3-butadiene and sulphur needs to be explained.

Concept Introduction : Cross linked polymers are polymers where cross linking of monomer units occur to produce a three dimensional (3D) network polymers. These polymers are rigid, hard and brittle due to network structure. Some examples of cross linked polymers are melamine formaldehyde, bakelite etc.

(c)

Interpretation Introduction

Interpretation: The reason of formation of stronger polymer on producing long chain of polystyrene needs to be explained.

Concept Introduction : Homopolymerization of styrene results a polymer whose name is Polystyrene.

  

(d)

Interpretation Introduction

Interpretation: The reason of formation of stronger polymer on addition of a catalyst to make linear polystyrene needs to be explained.

Concept Introduction: Addition polymers like polypropylene, polyethylene, poly(vinyl chloride), and polystyrene are linear or branched polymers possessing little or absence of cross-linking. Due to this, they are thermoplastic materials, which flow easily on heating and can be molded to different shapes.