This question is about condensation polymers.
State the names of two classes of organic molecules that can take part in condensation polymerisation.
Draw the structure of the dicarboxylic acid whose formula is C4H6O4. The functional groups should be displayed clearly.
State the IUPAC name of the dicarboxylic acid in part (b)
Draw one repeat unit of the polymer formed when C4H6O4 polymerises with diethylamine, H2NCH2CH2NH2.
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The structure of a synthetic polyester is shown below.
Deduce the structures of two monomers used to make this polyester.
One of the monomers is called benzene-1,4-dicarboxylic acid. State the name of the other one.
Name the other product of the reaction between the two monomers in part (b).
Benzene-1,4-dicarboxylic acid will also react to form a polyamide.
Which of the three molecules could react with benzene-1,4-dicarboxylic acid to form a polyamide?
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This question is about hydrolysis of polymers.
What is meant by a hydrolysis reaction?
Describe the reaction conditions and state what occurs to the polyester during acid hydrolysis.
Outline the difference in the product(s) between acid and base hydrolysis of a polyester.
Draw structures for the products of acid and base hydrolysis of the following polymer:
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Valylalanine shown in Fig. 1.1, is an example of a dipeptide composed of two amino acids, valine and alanine.
When this compound is placed in acidic conditions, two species are formed.
Draw one of these two species.
Fig. 1.1
A dipeptide made from the amino acids cysteine and tryptophan is shown in Fig.1.2 . Cysteine contains a sulphur molecule.
Fig. 1.2
Draw the structure of the amino acid tryptophan.
Amino acids such as serine shown in Fig. 1.3 will form polyamide links. Polyamides will contain the same type of links and these polymers can be used to form fibres suitable for weaving. Polymers formed from alkenes by additional polymerisation are usually took weak for this purpose.
Fig. 1.3
In terms of intermolecular forces between the polymer chains, explain why polyalkenes are not suitable to be used as fibres for weaving.
Explain why the molecule NH2CH2CH2COCl can form a condensation polymer with itself.
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Nylon is an example of a synthetic polyamide and contains the same links as polypeptides. Nylon is the general name for a family of polyamides. A section of a nylon polymer is shown in Fig. 2.1.
Fig 2.1
Draw the structures of two monomers that could be used to make this nylon.
[2]
State the type of polymerisation involved in the formation of this nylon.
[1]
Nylon can be used to make clothing. Suggest why nylon should be protected from spillages of strong acids and alkalis.
Nomex shown in Fig. 2.2 has a higher melting point than nylon and is used to make the flame resistant body suits worn by racing drivers.
Suggest a reason why the melting point of Nomex is higher than that of nylon.
Fig. 2.2
[2]
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Polyurethanes are polymers made by the reaction of a diisocyanate with a diol as shown in Fig. 3.1. R1 and R2 are hydrocarbon groups.
Fig. 3.1
Lycra® in Fig. 3.2 is a polyurethane formed from the diisocyanate P and HOCH2CH2OH.
Fibres of Lycra® are strong due to the intermolecular forces between the polymer chains. Complete the table to identify two intermolecular forces responsible for this property and the group(s) involved.
| Intermolecular force | Group(s) involved |
Name one example of each of the following types of polymer.
| Type of polymer | Example |
| Synthetic polyamide | |
| Synthetic polyester |
Fig. 3.3 shows the repeat unit of Nylon 66.
Draw the two products from the hydrolysis of Nylon 66.
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[2]
A section of polypeptide was hydrolysed and the following amino acids were identified.
| Amino Acid | Formula |
| T | CH3CH(NH2)CO2H |
| U | C6H5CH2CH(NH2)CO2H |
| V | H2N(CH2)4CH(NH2)CO2H |
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Polymers consist of monomers joined together by undergoing either addition or condensation polymerisation.
Fig. 1.1 shows a dicarboxylic acid and a diol that can be used in a general condensation polymerisation reaction.
Fig. 1.1
Draw one repeat unit for this polymerisation.
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In terms of n, state the number of molecules of water formed in the condensation polymerisation reaction of a general dicarboxylic acid and a general diol as shown in Fig. 1.1.
Using displayed formulae, write the balanced equation for the condensation polymerisation of the two monomers, propanedioyl dichloride and butane-1,4-diol.
Suggest an alternative pair of monomers that will produce the polymer from part (c).
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Lactic acid has the structural formula, CH3CHOHCOOH.
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Poly(lactic acid) is a thermoplastic polyester that can be prepared from lactic acid. It is a renewable material used widely in 3D printers.
Explain why lactic acid can be polymerised.
Polylactic acid contains methyl groups.
Poly(lactic) acid can be prepared using a different monomer.
Draw the skeletal formula of this monomer.
Give the systematic name of another monomer that could make poly(lactic acid).
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systematic name ................................................................................
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Kevlar ® has a variety of uses, including bulletproof vests and puncture resistant tyres, due to its strength and being lightweight. Nomex ® is most commonly used as a lining of the overalls worn by racing drivers and their pit crews as well as in the personal protective equipment of firefighters due to its flame resistant properties.
Nomex ® is made from 1,3-diaminobenzene and 1,3-benzenedicarboxylic acid.
Draw the skeletal structures of these monomers.
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Draw the structure of the Nomex ® polymer.
Kevlar ® is made from 1,4-diaminobenzene and 1,4-benzenedicarboxylic acid.
Draw two repeat units of the polymer to show the strongest intermolecular force in Kevlar ®.
State whether Kevlar ® or Nomex ® will have the higher melting point.
Explain your answer.
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