Composites, Smart Materials
& Biodegradable Materials
Explore materials whose performance comes from combination, environmental response or end-of-life behaviour.
By the end of class, you should be able to…
Explain composites
Show why combining materials can enhance performance.
Recognize smart responses
Connect stimulus → material response → design application.
Explain biodegradability
Connect end-of-life behaviour to design out waste.
Apply in context
Select when these material types are appropriate—not just novel.
Combine materials so the whole has a more useful property set.
A composite uses two or more constituent materials that retain distinct roles while working together.
Tailor strength / stiffness
Reinforcement can carry load efficiently.
Reduce mass
Performance can improve without simply adding more material.
Control durability
Matrix/coating can protect a vulnerable reinforcement.
Balance trade-offs
A composite can combine properties difficult to obtain from one material alone.
Carbon-fibre composite
Fibres provide reinforcement; polymer matrix binds/protects and transfers load.
Reinforced concrete
Concrete performs well in compression; steel reinforcement supports tensile loading.
Plywood
Layers with alternating grain directions create more stable, useful sheet behaviour than a single comparable layer of wood.
The environment becomes an input.
Eyewear becomes darker in bright sunlight and clears indoors. Which response best describes this?
Need
Does the responsive behaviour solve a real user/product need?
Conditions
Will the stimulus range and response be reliable in the real environment?
System trade-offs
Cost, recoverability, energy, repair, sourcing and complexity still matter.
End-of-life behaviour can be designed.
Biodegradable materials break down in the environment after disposal or at the end of useful life.
Context matters
A material may need specific biological/environmental conditions to break down effectively.
Function first
It must still meet safety/performance needs during its useful life.
System fit
Biodegradability is most useful when the collection/end-of-life pathway supports it.
Biomaterial describes origin; biodegradable describes end-of-life behaviour.
Biomaterials are created by, or derived from, biological organisms. Some biomaterials are biodegradable, but the terms are not synonyms.
Circular-economy link: suitable biomaterials can support biological recovery pathways when the wider end-of-life system is designed for them.
| Material strategy | Core idea | Typical design question |
|---|---|---|
| Composite | Combine constituents | Can combined properties outperform one material? |
| Smart material | Respond to stimulus | Can the material itself perform a useful response? |
| Biodegradable material | Break down through microorganisms in suitable conditions | Does the end-of-life pathway actually support biodegradation? |
Before you leave…
Material Selection
Keep the evidence chain moving: user → research → decision → test.
Explain today’s key ideas without notes, then apply one idea to a different product, user or design context.