Polymers

Question 1

What is an addition polymer?

Answer 1

Made from monomers with C=C bonds which break to connect the monomers

Question 2

What is a condensation polymer?

Answer 2

Made out of chains of monomers but the monomers have different functional groups which can react and reject a species (usually water)

Question 3

What is a polyester?

Answer 3

Type of condensation polymer formed from a dicarboxylic acid and a diol

Same reaction that occurs in esterification

Question 4

What are the uses of some polyesters?

Answer 4

Fabrics
Clothing
Plastic bottles

Question 5

What are polyamides?

Answer 5

Condensation polymer made from a dicarboxylic acid and diamines

Same condensation reaction occurs to make amides

Question 6

What is an amide functional group?

Answer 6

H-N-C=O

Question 7

What is the structure of nylon and what are its uses?

Answer 7

[ -NH-(CH2)6-NHCO-(CH2)4-C=O-]

Fabrics used in textiles

Question 8

What is the structure of Kevlar and what are it’s uses?

Answer 8

[-NH-aromatic-NHCO-aromatic-C=O-]

Used for bullet and stab proof vests

Question 9

Why are polyamides so strong?

Answer 9

Due to their ability to form hydrogen bonds

Question 10

Why is Kevlar so strong?

Answer 10

Kevlar strength is due to the rigid chains and their ability of the flat aromatic rings to pack together held by strong intermolecular forces (hydrogen bonds)

Question 11

What are polypeptides?

Answer 11

Condensation polymer made from amino acids as their monomers.

Amino acids have a carboxyl group and an amine group and can act as a monomer with themselves to form a polypeptide

Question 12

What happens during the acid hydrolysis of nylon?

Answer 12

Fast reaction
H+ / H2O

Amino acts as a base and accepts a proton forming a diammonium

Question 13

What happens during the alkali hydrolysis of nylon?

Answer 13

Slow reaction
NaOH / H2O. (Heated)

Forms a diamine and a carboxylate salt

Question 14

What happens during the acid hydrolysis of polyesters?

Answer 14

Slow reaction
Strong aqueous acid

Forms a dicarboxylic and a diol

Question 15

What happens during the alkali hydrolysis of polyesters?

Answer 15

Fast reaction
NaOH / H2O

Forms a carboxylate salt and a diol

Question 16

Why are addition polymers not biodegradable?

Answer 16

The non polar C=C bonds un reactive and therefore will not break down in the natural environment

They are sent to landfill sites or incinerated

Question 17

What are the issues with the disposal of addition polymers?

Answer 17

Landfill:
Damage to wildlife
Make leak toxic chemicals into the environment

Incineration:
Burning polyalkenes increases CO2 emissions and therefore contributes to global warming.
Incomplete combustion leads to toxic CO or soot
Other toxic chemicals may be released

Question 18

How are condensation polymers disposed of?

Answer 18

Undergo hydrolysis
Hey contain polar C=O bonds which are susceptible to attack via nucleophiles

Polyesters and polyamides are potentially biodegradable

Question 19

What are the advantages and disadvantages of recycling or remoulding polymers?

Answer 19

All polymers can potentially be recycled and melted to be remoulded

Advantages:
Saves diminishing crude oil reserves
Energy input to oil refining not needed
Plastic doesn’t end up in landfill

Disadvantages:
Plastics must be collected sorted and transported which is expensive and requires energy