Polymers Flashcards
Acrylic properties a few uses
- hard
- can be transparent
- resistance to weathering
- scratches easily
- stiff
- brittle
- good electrical insulator
signs + covers for car lights
HIPs properties and a few uses
- tough
- impact resistant
- lightweight
- hard
kids toys, yoghurt pots, fridge liners
HDPE properties and a few uses
- hard
- stiff
- great chemical resister
plastic bottles, tubing pipes
Polypropylene properties and a few uses
- tough
- hard
- fatigue resistant
- good chemical resistant
- lightweight
- flexible
- scratches easily
Toys, DVDs, food packaging, bottle caps
What is epoxy resin and uses
- Mixed with a hardener and left to set
- Can be used to make adhesives and flooring
What is melamine formaldehyde (MF) and uses?
- Scratch, water and stain resistant and is harder
- used to laminate work surfaces children’s cups and dishes
What is phenol formaldehyde and uses
- Tough and heat resistant
- often in black in colour
- used for saucepan handles
What is polyester resin (PR) and uses?
- Combined with fibreglass
- produce GRP
- used for pipes
What is urea formaldehyde (UF) and uses?
- Hard
- brittle
- rigid
- excellent insulator
- used for plug, sockets, switches, and toilet seats
What are the four key stages/processes of polymers?
- Crude oil is extracted from the Earth to
- The oil is processed in a refinery factory to separate different component compounds (fractional distillation) which are cracked to make monomers then linked to make chains called polymers
- Plastic is initially made into millions of pellets (a stock form)
- The pellets are melted, then moulding into shapes by manufacturers.
What are the stock forms of polymers?
- Sheets
- rods
- powders
- granules
- foam
- films
They are sold by length, width, gauge and diameter
Injection moulding and some examples
- Most widespread and versatile process
- high set up costs, low production costs
- mass produced items
- Dimensions and shapes can be accurately controlled
- goes into the hopper, spun around on the screw and injected into the mold
kettles, toys and chairs.
Blow molding and some examples
- Short tube of extruded plastic is trapped in an mold
- air is blown so plastic takes the shape of the mould and cavity.
Typical products are bottles made from PET or PP
Extrusion and some examples
- A form of moulding that makes a continuous shape
- It goes into the ram and then gets chopped so all parts are equal
a straw or curtain rod or plastic sheet or pipe or garden hose 
Vacuum forming and some examples
- Produces simple shapes from the thermoplastic sheet
- sheet is heated until soft then vacuum drawers material over mold
- Commonly used materials include HDP and HIP and PVC
- mold must be produced with a draft angle at least 3°
toys and pill packaging 💊