Polyesters and Polyamides

Condensation polymers

• Any kind of polymer formed through monomers joining, and a small molecule is formed as a by-product, such as water or HCl

• They are formed with functional groups at both ends of the molecule

Reactions

Condensation Polymers: Diacid + Diol

Condensation Polymers: Diacyl chloride and diol

Condensation Polyamides: Dicarboxylic acid and diamine

Properties of condensation polymers

• Polyesters: Used as wool, cotton substitutes, carpet and rugs. Bullet proof vests and some flame-retardant clothing are made from polyesters

• Polyamides: Elastic and used in underwear, fishing nets and synthetic fibres

Why are polyesters and polyamides biodegradable?

• The C=O absorbs radiation so the ester linkage is now hydrolysed

• Reason: It contains a polar C-O bond so the delta positive C can be attacked by the nucleophile

Hydrolysis of Polyesters: Acid and Base hydrolysis

Hydrolysis of Polyamides

Similar to the hydrolysis of polyesters except the CONH group is hydrolysed

Calculations involving polymers: 2 different monomers

Calculations involving polymers: Bifunctional monomer

Advantages of recycling polyalkenes

• Recycling saves using crude oil to make plastic

• It reduces landfill

Disadvantages of recycling polyalkenes

Plastics need to be collected, transported and sorted which uses energy and power and is therefore expensive

How is a polymer formed from the monomer molecules

π Bond breaks, many molecules join