Condensation Polymers Flashcards
How can alkenes form polymers?
By addition polymerisation
What are polyesters and polyamides?
- Polyesters and polyamides are two important condensation polymers made on an industrial scale
- Carboxylic acids and their derivatives are common starting materials for their preparation
What is needed for condensation polymerisation?
Two different functional groups are needed
What is condensation polymerisation?
Condensation polymerisation is the joining of monomers with loss of a small molecule, usually water (the condensation) or hydrogen chloride
What happens in making polyesters?
- When making a polyester, monomers are joined together by ester linkage in a long chain to form a polymers
- Polyesters can be made from one monomer containing both a carboxylic acid and an alcohol group or from two monomers, one continuing two carboxylic acid groups and tho the containing two alcohol groups
Describe how polyesters are made from one monomer containing two different functional groups
- For this type of polyester formation, only one monomer is involved containing both different functional groups, -a hydroxy group (-OH) and a carboxyl group (-COOH)
- Poly(glycolic acid) (PGA) is the simplest polyester of this type, made by condensation polymerisation of its monomer, glycolic acid HOCH2COOH
- Glycolic acid contains both a hydroxyl group and a carboxyl group
What happen in the formation of PGA?
The carboxylic acid group in one molecule of glycolic acid reacts with the alcohol group of another molecule of glycolic acid to form the ester linkage an water
Describe lactic acid
- Lactic acid, HOCH(CH3)COOH, also undergoes condensation polymerisation to form poly(lactic acid) (PLA)
- Lactic acid is derived from maize, making its production much more sustainable than polymers derived from fossil fuels
What does PLA and PGA have in common?
Both PLA and PGA are biodegradable polymers
What is needed for polyesters made from two monomers each containing two function groups?
- For this type of polyester formation, two different monomers are involved, each with different functional groups
1. One monomer is a diol, with two hydroxyl groups
2. One monomer is a dicarboxylic acid, with two carboxyl groups
Describe Terylene
- Terylene is a condensation polymer made from the reaction between two monomers
1. Benzene-1,4-carboxylic acid (HOOCC6H4COOH)
2. Ethane-1,2-diol (HO(CH2)2OH)
Describe the formation of Terylene from its monomers
During the condensation reaction a hydroxyl group on the diol reacts with a carboxyl group on the dicarboxylic acid forming an ester linkage and water
What is Terylene?
- Terylene (polyethylene terephthalate) is often shortened to PET and has many diverse uses ranging from clothing to plastic PET bottles
- Polyesters are also used for electrical insulation
What are polyamides?
Polyamides are condensation polymers formed when monomers are joined together by amide linkages in a along chain to form the polymer
How can polyamides be made?
-As with polyesters, polyamides can be made from one monomer containing both a carboxylic acid (or acyl chloride) and an amine group, or from two monomers one continuing two carboxylic acid groups (or acyl chlorides) and other containing two amine groups