Molecular structures of plastics

Question 1

Why do we modify polymers?

Answer 1

To give a wide variety of properties to a material

Question 2

How do we modify polymers?

Answer 2

To modify polymers we need to change the arrangements of molecules and how they are held together

Question 3

How does changing molecular arrangement affect the properties of the material?

Answer 3

By changing the arrangement of molecules in the polymer we either make the molecules further apart or closer together so there are less or more forces of attraction between molecules.
The stronger the force the more force is required to separate them and so the harder, stronger or higher boiling point etc it can have

Question 4

What different methods are there of modifying polymers?

Answer 4

Increasing chain length,
Cross-linking,
The addition of plasticizers,
Increasing crystallinity

Question 5

What does increasing chain length do?

Answer 5

Increasing chain length makes the molecule chains longer and so there are more IMFs between the chains and it requires more energy to seperate making them stronger

Question 6

What does cross linking do?

Answer 6

It adds links between molecule chains so that they would require more energy to separate, and therefore it increases melting point.
Aka vulcanisation

Question 7

What does the addition of plasticizers do?

Answer 7

Adding plasticizes pushes molecule chains further apart from each other so that there is less force between them and less energy is required to separate them, making the polymer softer

Question 8

What does increasing crystallinity do?

Answer 8

Increasing crystallinity means that the molecule chains are flatter and so closer together, increasing IMFs and the polymers tensile strength.
It is done by drawing polymers through a tiny hole