polymers Flashcards
What are the two main types of condensation polymers
- Polyesters - formed from carboxylic acids and alcohols.
- Polyamides - formed from carboxylic acids and amines.
What are the uses of Terylene
Carpets, clothing.
Heat treated polyesters used for drinks bottles
When an amine and a carboxylic acid react what is made
amide
An amide functional group is another name for a peptide link.
Polymers containing amide links are known as polyamides or polypeptides.
What are the two types of monomers made from polyamides
• One monomer is a dicarboxylic acid.
• One monomer is a diamine.
What are the properties and uses of nylon
Nylon is used as fibres in clothing
Properties: Elastic, strong abrasion resistant
What are the properties and uses of Kevlar
Kevlar is used in the manufacture of body armour and crash helmets.
Properties: Strong, light and heat resistant
Condensation Polymers
Condensation polymers can be hydrolysed under acidic or basic conditions.
a. Hydrolysis of Polyesters
Heating a polyester with aqueous acid such as HCl hydrolyses ester links, giving the monomer unit(s) of the polymers.
Heating a polyester with aqueous base such as NaOH also hydrolyses the ester links; alcohols are still formed but the salts of the carboxylic acid groups are formed.
b. Hydrolysis of Polyamides.
Heating a polyamide with aqueous acid such as HCl hydrolyses the amide links, giving a carboxlic acid group and the ammonium salt (NH3+) of the amine groups
Heating a polyamide with aqueous base such as NaOH also hydrolyses the amide links; amines are formed but the salts of the carboxylic acid groups are formed.
Addition Polymers
Addition polymers are not biodegradable. Bacteria and enzymes carry out hydrolysis reactions. As addition polymers have no polar bonds they cannot be hydrolysed.
At present these types of polymers are either incinerated or buried.
Both of these have significant environmental issues.
