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
Describe the formation of polyamides from one monomer with two functional groups
- Amino acid contain both an amine group and a carboxylic acid group
- Amino acids undergo condensation polymerisation to form polypeptides or amino acids
- A polypeptide or protein contains many different amino acids all linked together by amide bonds
- When an amide bond is formed, water is lost
Describe the formation of polyamides from two monomers each with two functional groups
Polyamides can be made by the reaction of a dicarboxylic acid (or acyl chloride) with a diamine
What are two ways that nylon can be synthesised?
- From reaction of hexanedioic acid and 1,6-diaminohexane (synthesis of Nylon from the reaction of a diamine with a dicarboxylic acid)
- From the reaction of hexanedioyl chloride and 1,6-diaminohexane (synthesis of Nylon from the reaction of a diamine with a diacyl chloride)
Describe the formation of nylon
- Different types of nylon can be made by varying the cabronacahin length
- During the condensation reaction an amide bond forma between the amine on one monomer and the carboxyl (or acyl chloride) group on the other monomer
How can polyesters and polyamides be hydrolysed? (condensation polymers)
Using hot aqueous alkali such as sodium hydroxide or by hot aqueous acid such as hydrochloric acid
- Acid: extra h and + on N
- Alkali e.g. NaOH, O-Na+ instead of COOH
Describe hydrolysing polyesters
Poly(Trimethylene terephthalate) (PTT) is a polyester used in the manufacture of carpets and clothing fabric (look at diagram of acid and base hydrolysis)
Describe hydrolysing polyamides
Nomex is a synthetic heat and fire-retardant polyamide, used in oven gloves and in the fire-protective suits worn by Formula 1 racing drivers and pit crew (look at diagram of acid and base hydrolysis)
What are the properties of addition polymerisation?
- Monomer contains a C=C double bond
- Backbone of polymer is a continuous chain of carbon atoms
E.G of monomer CICH=CHCH3
What are properties of condensation polymerisation?
- Two monomers each with two functional groups
- One monomer with two different functional groups
- Polymer contains ester or amide linkages
E.G of monomers: HOOCCH2COOH and HOCH2CH2OH
H2NCH2COOH
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Calculations10
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Spectroscopy23
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Introduction to Organic Chemistry24
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Alkanes13
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Alkenes47
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Alcohols20
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Haloalkanes23
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Chromatography and Spectroscopy59
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Carbonyls49
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Aromatic Compounds55
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Organic Synthesis 136
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Amines, amino acids and polymers18
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Amino acids, amides and chirality26
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Condensation Polymers25
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Organic Synthesis 1.511
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Organic Synthesis 221
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Organic Synthesis 2.530
