Performance characteristics of materials Performance characteristics of papers and boards - Elastomers — AQA A-Level Design and Technology: Product Design
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Performance characteristics of materials Performance characteristics of papers and boards - Elastomers explained
Elastomers are polymers with lightly cross-linked chains that stretch under load and recover their shape when the load is removed.
Read the full explanation
To explain suitability for a given application, name the application, identify the demand it places on the material, then link that demand to a specific property. For a car tyre, high elasticity and abrasion resistance allow repeated deformation on the road; for a seal or gasket, resilience and resistance to compression set keep the joint tight; for a shoe sole, grip and flexibility matter. Weakly cross-linked elastomers stretch more; more heavily cross-linked ones are harder and stiffer. Consider also environmental limits such as heat, oils or UV, and note that elastomers are generally not easily recycled.
Your focus
- Explain how cross-linking gives elastomers their elastic recovery.
- Relate named physical and mechanical properties to the demands of specific applications.
- Evaluate the suitability of an elastomer against service conditions and alternatives.
Performance characteristics of materials Performance characteristics of papers and boards - Elastomers exam tips
Marking Points
- Defines elastomers as polymers able to undergo large elastic deformation and recover their original shape.
- Explains that light cross-linking allows chain stretching and recovery, giving elasticity and resilience.
- Names a specific application and identifies the demand it places on the material, such as sealing, grip, cushioning or vibration isolation.
- Links that demand to a named physical or mechanical property, for example elasticity, resilience, abrasion resistance, hardness or compression-set resistance.
- Considers relevant environmental or service limitations such as heat, oil, UV or recyclability where they affect suitability.
- Compares elastomers with alternatives where the application could use a different material, justifying the choice.
Examiner Tips
- 💡Structure each paragraph as application, demand, property, justification to keep the explanation focused.
- 💡Use precise property terms such as resilience, elasticity, abrasion resistance and compression set rather than vague words.
- 💡Include at least one limitation or comparison to show balanced judgement of suitability.
Common Mistakes
- Describing elastomers as simply 'stretchy' without naming a property or linking it to an application; correct this by naming elasticity or resilience and the specific use.
- Confusing elastomers with thermosetting plastics; correct this by explaining the light cross-linking that permits recovery rather than a rigid network.
- Ignoring service conditions such as heat or oil; correct this by stating how these limit or support the choice for the application.