Condensation Polymerisation

Active learning works for condensation polymerisation because students need to visualize the invisible—how functional groups link and how small molecules exit the reaction. Building models, handling materials, and comparing real polymers make abstract concepts concrete, helping students move from memorization to genuine understanding.

• Year 11
• Chemistry
• 4 activities
• 30 min–45 min

Learning Objectives

1. Differentiate between addition and condensation polymerisation mechanisms by identifying the presence or absence of a small molecule byproduct.
2. Explain the formation of a polyester from a diol and a dicarboxylic acid monomer, illustrating the ester linkage and the elimination of water.
3. Compare the properties and predict the uses of polyesters and polyamides based on their respective repeating units and functional groups.
4. Synthesize the repeating unit of a condensation polymer given its constituent monomers.

Jigsaw

⏱ 30 min·Pairs

Model Building: Polyester Linkages

Provide ball-and-stick kits for pairs to connect diol and dicarboxylic acid monomers, removing water 'beads' each step. Students draw the repeating unit and predict properties. Discuss differences from addition polymers as a class.

Prepare & details

Differentiate between addition and condensation polymerisation.

Facilitation Tip: During Model Building: Polyester Linkages, circulate with molecular model kits to ensure students correctly orient functional groups before snapping monomers together.

Setup: Flexible seating for regrouping

Materials: Expert group reading packets, Note-taking template, Summary graphic organizer

• Understand
• Analyze
• Evaluate
• Relationship Skills
• Self-Management

Jigsaw

⏱ 45 min·Small Groups

Microscale Synthesis: Nylon Rope Trick

Mix diamine solution with acid chloride at the interface of two beakers; students pull continuous nylon fibres. Test fibre strength by stretching. Groups record observations on amide formation and properties.

Prepare & details

Explain the formation of a polyester from its monomers.

Facilitation Tip: During Microscale Synthesis: Nylon Rope Trick, demonstrate the reagent addition technique slowly so students observe the film formation at the interface.

Setup: Flexible seating for regrouping

Materials: Expert group reading packets, Note-taking template, Summary graphic organizer

• Understand
• Analyze
• Evaluate
• Relationship Skills
• Self-Management

Jigsaw

⏱ 35 min·Small Groups

Card Sort: Monomers to Polymers

Distribute cards showing monomers, linkages, and uses. Small groups sequence them into polyester or polyamide chains, justifying choices. Whole class shares and corrects.

Prepare & details

Compare the properties and uses of different types of polymers.

Facilitation Tip: During Card Sort: Monomers to Polymers, have students justify their pairings aloud to uncover misunderstandings before moving to the next set.

Setup: Flexible seating for regrouping

Materials: Expert group reading packets, Note-taking template, Summary graphic organizer

• Understand
• Analyze
• Evaluate
• Relationship Skills
• Self-Management

Jigsaw

⏱ 40 min·Small Groups

Properties Station Rotation: Polymer Tests

Stations test polyester film flexibility, nylon thread strength, and PET bottle durability with weights and bends. Groups rotate, tabulating data to link structure to use.

Prepare & details

Differentiate between addition and condensation polymerisation.

Facilitation Tip: During Properties Station Rotation: Polymer Tests, assign roles so every student handles samples and records observations, not just one group member.

Setup: Flexible seating for regrouping

Materials: Expert group reading packets, Note-taking template, Summary graphic organizer

• Understand
• Analyze
• Evaluate
• Relationship Skills
• Self-Management

Teaching This Topic

Teach condensation polymerisation by starting with students’ prior knowledge of functional groups, then immediately connecting theory to physical models and observable reactions. Avoid long lectures on mechanisms—students learn better by doing and discussing errors in real time. Research shows that tactile model building and microscale experiments improve retention of polymer chemistry concepts over traditional chalk-and-talk methods.

What to Expect

Successful learning looks like students correctly predicting polymer structures from monomers, identifying by-products, and explaining how bond types determine polymer properties. They should confidently explain why condensation polymerisation produces water or HCl, and distinguish it from addition polymerisation without prompting.

Watch Out for These Misconceptions

Common Misconception

During Model Building: Polyester Linkages, watch for students who assume all monomers link without losing atoms.

What to Teach Instead

Have students count hydrogen and oxygen atoms in two monomers versus one repeat unit of the polyester. When they see two fewer hydrogen atoms and one fewer oxygen atom, prompt them to account for the missing atoms as water molecules.

Common Misconception

During Card Sort: Monomers to Polymers, watch for students pairing monomers incorrectly and assuming all polymers form the same way.

What to Teach Instead

Ask groups to explain their pairings using the terms ‘functional group’ and ‘by-product.’ If they can’t justify, have them re-sort with the rule that condensation requires two reactive ends and produces a small molecule.

Common Misconception

During Properties Station Rotation: Polymer Tests, watch for students attributing differences in flexibility solely to chain length rather than bond type.

What to Teach Instead

Guide students to compare the ester and amide bonds in their samples. Ask them to sketch the linkages and connect the polarity and hydrogen bonding in amides to the greater stiffness observed in nylon.

Assessment Ideas

Exit Ticket

After Model Building: Polyester Linkages, distribute the monomers for PET and ask students to draw the repeating unit and label the ester linkage formed, then submit before leaving.

Quick Check

After Properties Station Rotation: Polymer Tests, show images of a fleece jacket, water bottle, and fishing line. Students write whether each is polyester or polyamide and explain their choice referencing bond types and observed properties.

Discussion Prompt

During Microscale Synthesis: Nylon Rope Trick, pause after the film forms and ask students to discuss: ‘How does the formation of water affect the mass of the nylon compared to the combined mass of the monomers?’ Listen for mentions of conservation of mass and the state of water as a by-product.

Extensions & Scaffolding

• Challenge students who finish early to design a polymer from unfamiliar monomers (e.g., lactic acid) and predict its properties and uses.
• For students who struggle, provide pre-labeled monomer cutouts for the card sort to reduce cognitive load while they focus on functional group recognition.
• Use leftover nylon film from the Nylon Rope Trick to test tensile strength with a simple spring scale, extending the investigation into material science.

Key Vocabulary

Condensation Polymerisation	A process where monomers join together to form a polymer, with the elimination of a small molecule such as water for each new bond formed.
Monomer	A small molecule that can react with other identical or similar molecules to form a larger polymer chain.
Polyester	A polymer formed by condensation polymerisation between monomers containing hydroxyl (-OH) and carboxyl (-COOH) functional groups, creating ester linkages.
Polyamide	A polymer formed by condensation polymerisation between monomers containing amine (-NH2) and carboxyl (-COOH) functional groups, creating amide linkages.
Ester Linkage	The functional group (-COO-) formed during the condensation reaction between a carboxylic acid and an alcohol, characteristic of polyesters.
Amide Linkage	The functional group (-CONH-) formed during the condensation reaction between a carboxylic acid and an amine, characteristic of polyamides like nylon.