Polyamides
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These are condensation polymers made when di amines
join with di acids.
A di amine contains 2 amino or amine groups in the
molecule.
Amide group NH2
Naming amines – end in amine, start with prefix for
number of carbons – CH2 CH2 NH2
This is ethyl amine
H
H
I
I
N-•
-N
a di amide
I
I
H
H
Polyamides
Example
H
H
I
I
N-•
-N +
I
I
H
H
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O
O
II
II
C–Δ-C
I
I
HO
OH
H
H O
O
I
I II
II
N -•- N – C – Δ – C
+ H2O
I
I
H
OH
H O
I II
The N – C
is the amide link.
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More info!
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Nylon is a polyamide.
It is a thermoplastic.
We can make different polyamides by altering
the number of carbons in the chain.
They can be used for ropes, clothing, pulleys.
The N-H and C=O groups in molecule allow for
H bonding. Resulting in very strong polymer.
Synthesis Gas
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This is a mixture of CO and H2.
It is made by steam reforming methane.
We use synthesis gas to make methanol.
This is oxidised to form methanal.
Methanal is used to make thermosetting
plastics.
The methanal is used to cross link the polymer
chains in a condensation reaction.
This gives a rigid 3D structure.
Examples – bakelite, urea – formaldehyde resin.
Thermosetting plastics.
New Polymers
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Kevlar
It is an aromatic polyamide which is extremely
strong because the linear molecules are rigidly
packed.
It is formed by condensation polymerisation.
Hydrogen bonds form between polymer sheets.
It is very strong and is used to replace steel in
car tyre radials, bullet proof vests, fencing
jackets, motor bike clothing. It is abrasive
resistant.
Poly( ethenol)
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This is a soluble plastic.
It is made by ester exchange:
Ethenyl ethanoate –> addition polymerisation –>
poly( ethenyl ethanoate) –> ester exchange –>
poly( ethanol).
It is used for laundry bags, dissolving stitches,
protective coatings over new cars.
The % of acid groups that are removed in the
reaction affects the intermolecular forces and
therefore the solubility.
Poly ( ethyne)
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This is an addition polymer made from
ethyne.
It can be treated to enable it to conduct
electricity.
This is due to the delocalised electrons
along the chain.
Conducting polymers make the
membranes for loud speakers.
Poly ( vinyl carbazole)
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This is an addition polymer.
It is exhibits photoconductivity – it
conducts much better when light shines on
it.
It is used in photocopiers.
Biopol
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This is a natural polymer that is
biodegradable.
It is made by certain bacteria.
It can be broken down by bacteria in the
soil.
Low Density Poly (Ethene) LDPE
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This can be altered to be photo
degradable.
It breaks up in sunlight.
Carboxyl groups are added to the chain
that can absorb UV light. The trapped
energy causes bonds, around the COOH
group, to break and the polymer breaks
into smaller pieces.