Polymer Science

These flashcards cover key concepts of polymer science, including types of polymerization, their advantages and disadvantages, and specific characteristics of polymers.

What occurs in the aqueous phase during emulsion polymerization?

Free radicals are generated and diffuse into the micelle to initiate polymerization.

List two advantages of emulsion polymerization.

1) High rate of polymerization. 2) Forms polymers with higher molar masses.

What is a disadvantage of emulsion polymerization?

The polymer needs additional clean-up and purification.

Define condensation polymers.

Polymers formed by functional group transformations of polyfunctional reactants, often with the loss of a small byproduct.

What initiators are commonly used in emulsion polymerization?

Water-soluble initiators like persulphates and hydrogen peroxide.

What is the critical micelle concentration (CMC)?

The concentration of surfactants necessary to form micelles in a solution.

Explain the difference between addition and condensation polymerization.

Addition polymerization involves linking unsaturated molecules, while condensation polymerization involves the loss of a small byproduct during the reaction.

What are block copolymers?

Polymers made of long sequences of one monomer linked to blocks of another monomer.

Describe the characteristic structure of crystalline polymers.

Polymers with an ordered arrangement of molecules, resulting in a high degree of crystallinity.

What does the degree of polymerization (DP) indicate?

The number of repeating units in a polymer chain.

What is the purpose of the Ziegler-Natta catalyst in polymerization?

To synthesize unbranched, high molecular weight polyethylene.

What types of bonds characterize a cross-linked polymer?

Linkages that create a three-dimensional structure, leading to increased stability.

What is meant by 'tacticity' in polymers?

The arrangement of substituents in a polymer chain, classified as isotactic, syndiotactic, or atactic.

Identify one common application of cationic chain-growth polymerization.

The polymerization of isobutylene to create polyisobutylene (butyl rubber).

What is required for a molecule to act as a monomer?

It must have at least two reactive sites or binding sites.