Chapter 31.SE, Problem 21AP

Interpretation Introduction

a) Syndiotactic polyacrylonitrile

Interpretation:

Draw the three-dimensional structure of the polymeric products given in the question.

Concept introduction:

Isotactic, syndiotactic, and atactic are the stereochemical forms. The polymer having the (-R) group on the same side of the macromolecule backbone (zig-zag bone) is known as isotactic polymer. An isotactic macromolecule consists of 100% meso diads.

Syndiotactic are the macromolecules in which the (-R) groups are arranged in an alternate manner along the long chain of the polymer. Gutta percha is also an example for Syndiotactic polymer.

In atactic form, the substituents are placed in a random manner along the long chain.

The important point to note here is that the polymer obtained from the chain growth polymerization mechanism must have chiral carbons to possess these structures. If the polymer formed does not have chiral carbon then it cannot occur in isotactic, syndiotactic and atactic forms.

Interpretation Introduction

b) Atactic poly(methyl methacrylate)

Interpretation:

Draw the three-dimensional structure of the polymeric products given in the question.

Concept introduction:

Isotactic, syndiotactic, and atactic are the stereochemical forms. The polymer having the (-R) group on the same side of the macromolecule backbone (zig-zag bone) is known as isotactic polymer. An isotactic macromolecule consists of 100% meso diads.

Syndiotactic are the macromolecules in which the (-R) groups are arranged in an alternate manner along the long chain of the polymer. Gutta percha is also an example for Syndiotactic polymer.

In atactic form, the substituents are placed in a random manner along the long chain.

The important point to note here is that the polymer obtained from the chain growth polymerization mechanism must have chiral carbons to possess these structures. If the polymer formed does not have chiral carbon then it cannot occur in isotactic, syndiotactic and atactic forms.

Interpretation Introduction

c) Isotactic poly(vinyl chloride)

Interpretation:

Draw the three-dimensional structure of the polymeric products given in the question.

Concept introduction:

Isotactic, syndiotactic, and atactic are the stereochemical forms. The polymer having the (-R) group on the same side of the macromolecule backbone (zig-zag bone) is known as isotactic polymer. An isotactic macromolecule consists of 100% meso diads.

Syndiotactic are the macromolecules in which the (-R) groups are arranged in an alternate manner along the long chain of the polymer. Gutta percha is also an example for Syndiotactic polymer.

In atactic form, the substituents are placed in a random manner along the long chain.

The important point to note here is that the polymer obtained from the chain growth polymerization mechanism must have chiral carbons to possess these structures. If the polymer formed does not have chiral carbon then it cannot occur in isotactic, syndiotactic and atactic forms.