Characteristics and properties of materials Flashcards
What are common thermosetting polymers?
Epoxy resin (ER) - Casting
Melamine Formaldehyde (MF) - Plastic Table wear
Polyester resin (PR) - Hard hats
Urea Formaldehyde (UF) - Plug Sockets
What are thermosetting plastics?
Plastics that can only be formed once and cannot be reshaped or recycled (they do not have shape memory)
What are the general properties of a thermosetting polymer?
- Cannot be reshaped
- Resistance to heat
- Good insulators
- Single use and can’t be recycled
What are common thermoplastics?
Polyamide (nylon)
PTFE
Polyester
Acrylic
ABS
PLA
What are the uses of ABS and some properties?
Vacuum construction
Keyboard keys
Lego bricks
Impact, heat and chemical resistance resistant, easily coloured,
What are the uses of High Impact Polystyrene and some properties?
CD Cases
Food safe packaging (e.g. yogurt pots)
Plates
Available in many colours
Lightweight
Strong
Hard, stiff, transparent, brittle, water resistance
not very durable
What are the uses of PLA and some properties?
3D printer filament
Bottles
Biodegradable medical devices
Water resistant
High Strength
Very mailable and pliable
What is a hardwood?
They are woods that come from deciduous trees that shed leaves in autumn. These grow slower than softwoods, less plentiful and thus more expensive
What are softwoods?
Woods that come from coniferous trees, which usually remain evergreen. These grow faster than hardwoods and usually have needles and pines instead of leaves.
What are examples of hardwoods?
Oak
Ash
Beech
Mahogany
Balsa
What are the general properties of hardwood?
They are generally more tough and durable than softwoods with a closer grain and used in higher end furniture and furnishing.
Balsa is the exception as it is very lightweight and soft making it great for model making
What are examples of softwoods?
Pine
Cedar
Spruce
Larch
What are the general properties of softwoods?
Tend to be paler in colour with a darker grain and are generally more lightweight than hardwoods.
They are popular for household construction and fencing
What are natural timbers?
Woods that require seaoning to lower moisture content prior to use
What are regenerated materials?
Materials that use recycled material and combines them to make a strong and durable materials.
This is also a eco approach to sourcing materials and follows the ‘cradle to cradle’ cycle.
What are the uses and properties of PVC?
Pipes
electrical insulation
Chemical containers
High chemical resistance
High impact strength
Can be extruded
What are examples of regenerated materials?
Blockboard - Plywood with veneers on exterior
Cellulose-based boards- Fibres
Chipboard- Mixing wood particles with epoxy resin
Medium density fibreboard (MDF)- Wood chips with resin
Paper
What are alloys?
A mixture of metals with an element to improve its properties or aesthetics
What are common alloys?
Brass
Pewter
Bronze
Stainless Steel
What are the properties of ferrous metals?
Low corrosion resistance (rusts)
Durable
Great tensile strength
Usually magnetic
Silver like in colour
Recyclable
Good conductors of electricity
Properties of non-ferrous metals
- High corrosion resistance (doesn’t rust)
- Easy to fabricate – machinability, casting, welding etc.
- Great thermal conductivity.
- Great electrical conductivity.
- Low density (less mass)
- Colourful (Aesthetically pleasing)
- Non-magnetic.
What is the trend in properties for mild to high carbon steel?
Low Carbon Steel- Ductile, Malleable, tough and poor corrosion resistance
Medium Carbon Steel- Harder than carbon steel but less ductile, malleable and tough
High carbon Steel (Cast Iron) - Hard outer layer but brittle core, good under compression
The more carbon, the more hard and brittle and less malleable and ductile the metal gets.
What are ferrous metals and some examples
Metals that contain iron, are magnetic and corrode meaning they will need added protection
Mild steel
Carbon steel
Cast iron
Wrought iron
