CAIE A-Level Chemistry 35.1 Condensation Polymerisation

Practise constructing polyester and polyamide repeat units and recovering monomers from linkages.

Exam points

pair bifunctional monomers or use one AB monomer to form ester or amide links throughout a chain
draw the requested number of repeat units with displayed linkages and continuation bonds at both ends
recover monomers by cutting each linkage and restoring the original –COOH, –OH or –NH2 groups

Covered syllabus points

35.1.1—Formation of polyesters 35.1.2—Formation of polyamides 35.1.3—The repeat unit of a condensation polymer 35.1.4—Monomer(s) present

[Maximum number: 3]

Lactic acid, $\mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{COOH}$ , is the only monomer needed to form the polymer polylactic acid, PLA.

(a)

Draw a short length of the PLA polymer chain, including a minimum of two monomer residues. The methyl groups may be written as $-\mathrm{CH}_{3}$ but all other bonds should be shown fully displayed.

Label one repeat unit of polylactic acid on your diagram.

[ 2 ]

(b)

Give the name of the type of polymerisation involved in the formation of PLA and the name of the functional group that forms between the monomers.
type of polymerisation
functional group

[ 1 ]

[Maximum number: 3]

(a)

1,3-diaminopropane, $\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}$ , can be used to make polyamides.

[ 3 ]

(i)

Identify one compound that would react with 1,3-diaminopropane to form a polyamide.

[ 1 ]

(ii)

Draw a section of the polymer chain formed from 1,3-diaminopropane and the compound you chose in (e)(i).

Your answer should:
- include four monomer residues (two of each type of monomer)
- show the amide link fully displayed
- clearly identify one repeat unit of this polymer.

[ 2 ]

trailing bonds

- two of each monomer residue, consistent with ei [1]

- repeat unit identified

- amide link showing $\mathrm{C}=\mathrm{O}[1]$

[Maximum number: 2]

Copper is a transition element and has atomic number 29.

Under certain conditions, ethane-1,2-diamine reacts with ethanedioic acid, $\mathrm{HO}_{2} \mathrm{CCO}_{2} \mathrm{H}$ , to form the polymer Z.

Draw the structure of this polymer, Z, showing two repeat units.

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Covered syllabus points

35.1 Condensation polymerisation question 1

Question (a)

Question (b)

35.1 Condensation polymerisation question 2

Question (a)

Question (i)

Question (ii)

35.1 Condensation polymerisation question 3