Polymer 2: Properties of polymer

Question 1

What are the two different states of polymers?

Answer 1

1. Crystalline

2. Amorphous

Question 2

Describe the properties of crystalline state?

Answer 2

1. Highly ordered arrays of molecules and atoms
2. Definite melting point
3. Anisotropic: orientations are all in different directions

Question 3

Describe the properties of Amorphous state?

Answer 3

1. Randomly orientated molecules and atoms
2. No definitive melting point
3. Some properties typical for liquids
4. Isotropic properties: orientations are in the same direction

Question 4

What is left after evaporation of KCl and a polymer like chitosan?

Answer 4

1. Crystals formed through low organic salts

2. Solution of chitosan will never form crystals (jelly like material)

Question 5

How do the ranges of crystallinity range from 0% to 90%?

Answer 5

1. 0% Amorphous

2. 90% crystalline

Question 6

What do the factors of crystallinity depend upon?

Answer 6

1. Chemical structure
2. Temperature
3. Processing conditions
4. Molecular Weight

Question 7

What are the only polymer that can be completely crystallised?

Answer 7

Proteins have a perfect order at any level

Question 8

What are the three different states for amorphous crystalline solids?

Answer 8

1. Glassy state
2. Rubbery state
3. Liquid state

Question 9

How can you test the different states for amorphous crystalline solids?

Answer 9

Hanging a weight from the polymer and seeing how far they stretch

Question 10

What does glass state temperature (Tg) mean?

Answer 10

The temperature required to turn glass from hard (glassy) to soft state (rubber)

Question 11

Give two examples when Tg is -75 and Tg is 100?

Answer 11

1. Tg= -75 represents the material that forms catheters (polyisoprene)
2. Tg=100 represents polystyrene

Question 12

What is plasticisation and what effect does it have on the glass state temperature?

Answer 12

1. When a substance is added that makes the material more soft such as water
2. Decreases glass transition temperature

Question 13

When a polymer has a glass transition state of above 100 degrees and below it, what state does it bring?

Answer 13

1. Above Tg=100 means it’s soft and rubbery

2. Below 100 degrees means it hard and glassy

Question 14

What is addition polymerisation and give an example?

Answer 14

1. When you form a large macromolecule from the addition of many monomers with double bonds
2. This can be many repeating groups which leads to Poly being added to the front of the chemical name
   Example: Vinyl acetate becomes poly (vinyl acetate)

Question 15

What is step growth polymerisation?

Answer 15

1. When the polymer is added to water (hydrolysis)
2. Products formed are then used

Example: breast implants

Question 16

What is Ring Opening Polymerisation?

Answer 16

1. Unstable ring is added alongside a catalyst and heated
2. Ring opening is formed
3. Biodegradable polymer is then formed which has applications in drug delivery

Question 17

What is chitin?

Answer 17

1. Natural polymer that’s found in animals such as crustaceans, fungi, insects and molluscs
2. Highly insoluble

Question 18

What is chitosan?

Answer 18

1. Pharmaceutical excipient
2. Soluble in water under slightly acidic conditions as the NH2 reacts
3. Used to form capsules

Question 19

How do you form chitosan from chitin?

Answer 19

1. You replace one functional group with NH2 in chitin

2. Deacetylation

Question 20

How do you form poly (vinyl alcohol) from Poly (vinyl acetate)?

Answer 20

By reaction Poly (vinyl acetate) (PVA glue) with NaOH to form poly (vinyl alcohol) which is used in ocular areas to form tears