Addition polymers

Question 1

How would I draw formation of poly(propene) from propene?

Answer 1

• Brackets “n” bonds
• Break C=C double bond, two bonds (extending to outside of brackets!)
• ## n in the right corner.

Refer to allery chem vid - if needs be

Question 2

How would you draw TWO propene molecules joining together to form poly(propene?)

Answer 2

• Break C=C double bond.
• Draw the two molecules, joined together within brackets.
• NO n in right hand corner, if Q specifically asking for joining of 2 molecules of propene!

Refer to allery chem vid - if needs be

Question 3

Properties of poly(alkenes)? What does this mean?

Answer 3

• Saturated molecules.
• Normally non-polar.
• This makes the poly(alkenes) unreactive because they are so stable.
• Means that they won’t break down well in landfills.

Question 4

What are addition polymers formed from?

Answer 4

• Addition polymers are formed from alkenes and substituted alkenes (ie. halogen attached!)

Question 5

Describe intermolecular forces that would be between MOST poly(alkenes) and what would cause these intermolecular forces to increase in strength.

Answer 5

• Van der Waals between the chains.
• Longer chain = larger surface area/ more closely chains can pack so more/ increased strength Van der Waals forces.
• Shorter polymer chains/ more branched chains tend to be more flexible/ weaker –> less Van der Waals forces.

Question 6

What intermolecular forces will be between poly(alkenes) with halogen? Significance of this?

Answer 6

• Permanent dipole-dipole attractions.
• Will make the poly(alkene) stronger compared to poly(alkenes) without halogen.

Question 7

What are plasticisers? What do they do?

Answer 7

• Materials added to polymers to change their properties.
• Make polymers more flexible / slide between polymer chains –> pushing them apart.
• Weakens IM forces between chains. Chains can slide over each other more, making polymer easier to bend.

Question 8

What is full name for PVC?

Answer 8

• Poly(chloroethene)

Question 9

Give 3 typical uses of PVC.

Answer 9

• Drain pipes.
• Electrical cable insulation/ clothing.

Question 10

Explain how properties of PVC can be modified using plasticiser.

Answer 10

• PVC: made of long, closely-packed polymer chains that are hard BUT brittle. Used in drain pipes.
• PVC w/ plasticiser added = more flexible. Used for clothing/ electrical cable insulation.

Question 11

True or False

Knowledge of production and properties of polymers has remained pretty stagnant over time.

Answer 11

• False!
• Knowledge of production and properties of polymers has DEVELOPED over time.
• Ie. making synthetic polymers over time with new uses/ properties ie. ones that break down more easily.

Question 12

Mock exam Q

State why PVC is non-polar.

Answer 12

C-C bonds are non-polar.