Polyesters and polyamides

Question 1

what two monomers make up a polyester?

Answer 1

the monomers have a carboxyl group (-COOH) and a hydroxyl group (-OH)

Question 2

what are the two common types of polyester?

Answer 2

1) polyesters made by reacting 2 different types of monomer units
2) polyesters made by reacting just one type of monomer unit

Question 3

Describe the condensation polymerisation that forms polyesters from two types of monomer units

Answer 3

• a bond forms between a hydroxyl group on the diol and a carboxyl group on the dicarboxylic acid
• an ester linkage forms, and water is formed

Question 4

what two monomers make up a polyamide?

Answer 4

• COOH (carboxyl)

- NH2 (amine)

Question 5

Compare condensation polymerisation with addition polymerisation

Answer 5

• addition polymers are made from one type of monomer only

- there is no product other than the polymer

Question 6

if the monomer contains a double bond, suggest the type of polymerisation

Answer 6

addition

Question 7

Uses of polyesters and polyamides

Answer 7

fibres in clothing

Question 8

With the hydrolysis of polyesters with an alkali, what is each ester linkage hydrolysed to?

Answer 8

• the sodium salt of a carboxylic acid (-COO-Na+)

- a hydroxyl group (-OH)

Question 9

what reactants are needed for the hydrolysis of polyesters?

Answer 9

readily hydrolysed by hot aqueous alkali (e.g. sodium hydroxide) but can also by hydrolysed by hot aqueous acid although it is much slower.
PRESENCE OF HEAT.

Question 10

When hydrolysing polyamides with a hot aqueous acid, what is formed?

Answer 10

the dicarboxylic acid is produced with an ammonium salt of the diamine

Question 11

when hydrolysing polyamides with hot aqueous alkali, what is formed?

Answer 11

• sodium salt of the dicarboxylic acid

- diamine

Question 12

with the hydrolysis of a polyester with an acid, what is it hydrolysed to?

Answer 12

monomer units of the polyester

Question 13

Give two examples of biodegradable polymers

Answer 13

Poly(lactic acid), made from lactic acid in corn starch

Poly(glycolic acid), made from glycolic acid in sugar cane

Question 14

What are photodegradable polymers and how do they work?

Answer 14

Photodegradable polymers are made to be broken down when exposed to sunlight for prolonged periods of time. This is because the C=O bond absorbs radiation and break.