CHAPTER:28
POLYMERISATION
Saction: 28.1 and 28.2
TYPES OF POLYMERZIATION
Condensation polymerization:
it’s a process where two monomers with
different functional groups react with each
other to form a polymer
•
When the two monomers join a small
molecule is given out like water or HCl
• Polyesters and polyamides are
examples of condensation
polymerization.
Addition polymerization:
the reaction in which many monomers containing
at least one C=C double bond form long chains of
polymers as the only product.
• the π-bond in each C-C bond breaks and then
the monomers link together to form new C-C
single bonds
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FORMATION OF POLYESTERS
This topic includes:
•
What is a polyester?
•
How is it formed
•
What is hydroxycarboxylic
acid
•
How is it formed?
What is a polyester?
• It’s a polymer formed when an alcohol diol bond with
a carboxylic acid diol.
• An ester bond is formed as a result
• Water is given out when the two monomers bond.
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How is it formed?
• Step 1: provide the correct monomers
It can be butane-1,2-diol
and 1,4-diolpropanoic acid
; what matters is the diol
functional groups
+
• Step2: bonding
The H from the ethane-1,2-diol and the OH from the
carboxylic acid will bond together to form a water
molecule
• Esterbond formation:
this structure will be
repeated to form a big
polymer
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What are hydroxycarboxylic acid?
• It’s another monomer used to make a polyester
• Two similar monomer are used
 Both have an alcohol functional group (OH) and a carboxylic
functional group (COOH)
 Thus its called HYDROXYCARBOXYLIC ACID.
How are they formed?
>Step 1: prepare the monomers:
Two hydroxy butanoic acid bond together and
as a result water is removed
>Step 2: bonding
Ester bond is formed!
Formation
Of
Polyamides
>What are polyamides
>Amino carboxylic acids
>Amide link
>Protein hydrolysis
>Formation of polyamides
>Making proteins
>Kevlar
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What are Polyamides?
• A polymer formed when two different monomers bond together
• An amide link is formed
• The monomers used are the ones that has a diamide(NH2)
group and a dicarboxylic acid group (COOH)
• Water is lost when the monomers bond
2 similar monomers can be used to make
polyamides however they must have both
diamide and dicarboxylic functional group
attached to them
AMIDE LINKAGE AND MONOMERS
Monomers used:
Amide linkage
• Diamide :
• Formed between Diamide and Dicarboxylic or
a Dioyl dichloride
• Dicarboxylic acid:
• Some times dioyl dichloride is used instead of
carboxylic as its more reactive, however its more
expensive
FORMATION OF POLYAMIDES:
• NYLON 6,6:
o Monomers used:
 1,6-diaminohexane
 Hexan-1,6-dioic acid
o The OH from dioic acid and the H from NH2 in diamino will bond to form water:
KEVLAR
• It’s another example of a polyamide polymer
• It’s when chains of polyamide line parallel to each
other, they will start to form hydrogen bonds
between them.
• This cause the polymer to be strong and flexible with
fire resistance properties
• Because its properties its also used in bullet proof vests
HOW ARE KEVLAR’S MADE?
• Step1: choose the correct monomer
• 1,4-diaminobenzene
It can be a normal hydrocarbon
chain rather than benzene
• Benzene-1,4-dicarboxylic acid
Dioyl dichloride can be used instead of
carboxylic here as well
• Step2: form nuemours amount of polymides
• Step3:Hydrogen bond
AMINO CARBOXYLIC ACID
• It is possible to form a polyamide using 2 similar monomers!
• For example:
• 6-aminohexanoic acid; it has an Amino and carboxylic acid functional
group.
• Two similar 6-aminohexanoic acid can bond to form Nylon-6,6!
MAKING PROTEINS
• proteins are polymers made from monomers called
amino acid
• Amino acid is an aminocarboxylic acid monomer!
MAKING PROTEINS
• Dipeptides can be produced by polymerising 2 amino acids together
• Polypeptides are made through polymerising more than 2 amino acids
together
PROTEIN HYDROLYSIS
• Protein can break to form amino acids again
• This process is called ‘hydrolysis’
• Water need to be supplied for this process to occur