2.1 Types of material

Comprehensive practice flashcards covering polymer types, timber properties, metal alloys, composites, smart materials, joining techniques, and safety regulations from the lecture transcript.

According to the transcript, what are polymers formed of?

Polymers are formed of molecules bonded together in long chains.

How do thermo polymers react when they are heated?

They soften and become malleable, allowing them to be deformed and moulded.

What is the molecular structure difference between a thermo polymer and a thermosetting polymer?

Thermo polymers have linear chains, while thermosetting polymers have a cross-linked structure.

Under what condition can thermo polymers be shaped via rotational moulding or injection moulding?

When they are in their plastic state.

What are the specific properties of Nylon (polyamide)?

Strong and tough.

Which polymer is described as chlorine-based and produces toxic by-products during production and disposal?

Polyvinyl chloride (PVC).

What is the source material for Polylactic acid (PLA)?

Renewable resources like corn starch or sugarcane.

How do thermosetting polymers set?

As a result of a chemical reaction between a resin and a hardener.

What volatile organic compounds (VOCs) do polyester resins release?

Styrene vapours.

What is the source of Polyhydroxy-alkanoates (PHA) biopolymers?

Microbial fermentation of sugars or lipids.

In terms of international recycling symbols, what do the numbers (resin indication codes) 1 and 2 represent?

$1$ is PET and $2$ is HDPE.

What is the classification difference between softwood and hardwood trees?

Softwood comes from coniferous trees (needles and cones), while hardwoods come from deciduous trees (shed leaves).

What is seasoning in the context of timber?

The process of drying out timber in a kiln or via air circulation so that it becomes strong and stable to use.

How are veneers defined in the notes?

Thin slices of wood, usually less than $3\,mm$ thick, glued onto core panels.

What are the properties and common uses of Oak?

Light brown color, strong and tough, open-grained; used for high-quality furniture and interior woodwork.

What is Chipboard made of?

Small chips of wood bonded together with resin and compressed to form sheets.

Describe the construction of Plywood.

Veneers of timber bonded together by resin and pressure, with the grain of each layer at right angles to the layers beside it.

What is a disadvantage of working with manufactured boards regarding recycling?

They are difficult to recycle due to the adhesives used during manufacture.

What are the two common methods for forming curved shapes in timber?

Steam bending and laminating.

What does the Forest Stewardship Council (FSC) logo indicate?

That the timber or paper comes from well-managed, sustainable forests.

From what ore is aluminium extracted?

Bauxite.

Define the property of 'Toughness' in metals.

Resistance to impact without breaking; the opposite of brittleness.

What are the typical melting points for Cast iron and Mild steel?

Cast iron is $1200^{\circ}C$ and Mild steel is $1600^{\circ}C$.

What is the composition of Stainless steel?

An alloy of iron typically with $18\%$ chromium, $8\%$ magnesium, and $8\%$ nickel.

What characterizes a Non-ferrous metal?

A metal or metal alloy that does not contain iron.

What is 'Verdigris'?

A green substance formed when copper corrodes.

What temperature and color signify the correct state for tempering a screwdriver blade?

$300^{\circ}C$ and a blue color.

What is the thickness of the hardened outer layer created during Case hardening?

$0.05\,mm$.

What is the composition of the alloy Duralumin?

Aluminium, copper ($3\%$), manganese ($1\%$), and magnesium ($1.5\%$).

What is 'Planishing' in metalworking?

A technique to smooth and refine sheet metal by lightly hammering it over a hard surface like an anvil.

What are the two components that make up a composite material?

A matrix (binder) and a reinforcement (strengthener).

What are the properties of Carbon-fibre reinforced polymers (CFRP)?

Extremely strong, lightweight, high stiffness, and corrosion-resistant.

Who is credited with revolutionizing prosthetic limbs using carbon fiber?

Van Phillips.

How is a 'Smart Material' defined?

A material whose properties change in response to external stimuli (heat, light, pressure, or electricity) and return to normal when the condition is removed.

At what temperature does Nitinol return to its original shape?

When heated beyond $90^{\circ}C$.

What are the pellets called that fuse at $62^{\circ}C$ and can be moulded into tough polymers?

Polymorph.

What are the properties of Graphene?

A single-atom-thick 2D material, stronger than steel with extreme electrical and thermal conductivity.

What was the cause of the Mars Climate Orbiter loss in 1999?

Engineers failed to convert British imperial measurements into metric units, causing the satellite to veer $60\,km$ off course.

Which hand tool is used for cutting curved lines in wood?

Coping saw.

What is the difference between a 'Through hole' and a 'Blind hole'?

A through hole goes all the way through the material; a blind hole only goes part way.

Define 'Tapping' in the drilling process.

Adding a screw-thread to the inside of a pilot hole using a tool called a 'tap'.

What are the two types of casting mentioned in the reforming processes?

Sand casting and Die casting.

What is the difference between temporary and permanent joining?

Temporary joining (like screws) can be taken apart; permanent joining (like welding) cannot be easily separated without damage.

At what temperature does soft solder typically melt?

Around $200^{\circ}C$.

What does 'M5 \times 45\,mm' signify on a bolt?

A metric bolt with a thread diameter of $5\,mm$ and a length of $45\,mm$.

What is 'Anodising' and why is it applied to aluminium?

A process using electrolysis to build protective layers to increase corrosion resistance and optionally add color.

Give an example of a self-finishing fabric.

Gortex (water-resistant) or Nomex (heat-resistant).

What does the COSHH acronym stand for?

Control of Substances Hazardous to Health.

Define 'Embodied energy'.

The total energy required to extract, process, manufacture, transport, and install a material or product.

Which machine tool melts and deposits plastic filament like PLA or ABS to build models?

3D Printing (Fused Deposition Modelling - FDM).