Physical Properties

Physical properties are measurable attributes of a material that can be observed without altering its fundamental chemical composition.

Density (ρ): Mass per unit volume. Critical when designing products where weight reduction is vital. 

Thermal Conductivity & Expansion: How well a material conducts heat, and how much it expands or contracts when temperature changes. 

Electrical Conductivity & Resistivity: The capacity to allow or resist the flow of an electric current. 

Melting Point: The temperature at which a solid transitions into a liquid, dictating suitable manufacturing processes like casting or thermoforming. 

In the structural frame of the LTA Pathfinder Airship, designers specified titanium hubs and carbon fibre composite tubes because of their extremely low density paired with high structural stiffness, maximizing flight and fuel efficiency. 

Similarly, the MOM Infant Incubator utilizes clear polycarbonate sheets for its canopy due to its high optical transparency and thermal insulation properties

Chemical Properties

Chemical properties describe how a material interacts, reacts, or degrades when exposed to other chemical substances or environmental elements.

• Corrosion Resistance: The ability to withstand chemical degradation caused by oxidation, moisture, or acids.

• Reactivity: Food Safety: Ensuring materials do not leach harmful chemicals or react when in contact with food, skin, or biological tissues.

• Hygroscopy: The degree to which a material absorbs moisture from its surrounding environment.

• Flammability: How easily a material ignites and sustains combustion.

Fast-food containers developed from mycelium (fungus root structures) must undergo testing for hygroscopic capabilities to ensure moisture from hot food does not compromise the container's structural stability or contaminate the meal

Mechanical Properties

Mechanical properties describe how a material behaves when subjected to external physical forces or loads.

Tensile & Compressive Strength: The maximum resistance to pulling (stretching) or pushing (crushing) forces before failure.

Stiffness & Young’s Modulus: The measure of a material's resistance to elastic deformation under stress.

Toughness: The capacity to absorb mechanical energy and deform plastically before fracturing.

Hardness & Malleability: Hardness resists surface indentation or scratching, while malleability allows a material to be hammered or rolled into thin sheets without cracking.

Ductility & Elasticity: Ductility allows a material to be drawn out into long wires, whereas elasticity enables it to return to its original shape after a load is removed

Beyond technical and visual parameters, real-world product design requires balancing financial viability, supply chain logistics, and environmental responsibility

A. Cost & Availability Constraints

• Raw Material & Processing Costs: High-performance materials (such as titanium or carbon fibre) incur substantial raw material and specialized tooling expenses, which must be offset by the product's retail value.

• Resource Availability & Supply Chains: Designers prioritize standardized, locally sourced components to minimize shipping lead times, transport emissions, and geopolitical supply risks.

B. Sustainability & Circular Economy Integration

• Biodegradable Materials & Biomaterials: Derived from biological sources (e.g., wood fibres, mycelium, bamboo), these materials naturally break down at the end of life without leaving toxic residues.

• Cradle-to-Cradle Philosophy: Selecting fully recyclable or compostable materials allows products to be safely re-absorbed into biological or industrial loops, effectively designing out waste.

• Take-Back Legislation & Recycling: Using highly recyclable metals (such as aluminium) or single-polymer structures makes end-of-life disassembly and material recovery economically viable.