8. Performance characteristics of polymers Flashcards
What are the polymer stock forms?
- powder
- very fine granule
- granules
- small particle
- sheet
- large flat sections in varying thickness
- foam
- solid foam made by including air or other gases
- film
- very thin sheet
- rods and other extrusions
- rods and extruded forms can be specific designed shape
- bar
- solid form, square or round
- tube
- hollow in cross section, square, rectangular or round
What are synthetic polymers made from?
- crude oil
- take hundreds of years to degrade
What is self-finishing?
- can be pigmented during manufacturing process to give colour and therefore requires no additional secondary finishing process
What are the three classifications of polymer?
- thermoplastic
- thermoset polymer
- elastomer
What is a thermoplastic?
- a material that can be reheated and reshaped repeatedly
- can be recycled after initial use
What is a thermoset polymer?
- a material that when heated undergoes a chemical change where molecules form rigid cross-links
- cannot be reheated and reshaped
What is an elastomer?
- a material that at room temp can be deformed under pressure and then upon the release of the pressure will return to its original shape
What are thermoplastics?
(examples)
- low-density polyethylene (LDPE)
- high-density polyethylene (HDPE)
- polypropylene (PP)
- high-impact polystyrene (HIPS)
- acrylonitrile butadiene styrene (ABS)
- polymethylmethacrylate (PMMA)
- nylon
- rigid polyvinyl chloride (uPVC)
- flexible polyvinyl chloride (PVC)
What are the properties of LDPE?
- very tough
- good chemical resistance
- weather proof
- available in translucent
- low level of rigidity
- safe working temp 65
What are the uses of LDPE?
- squeezy detergent bottles
- toys
- carrier bags
- bin liners
- general packaging
- food wrap film
- food trays
What are the properties of HDPE?
- tough
- weather proof
- good chemical resistance
- available in translucent
- safe working temp 65
What are the uses of HDPE?
- chemical drums
- jerry cans
- toys
- household and kitchenware
- long-life carrier bags
- buckets
- bowls
What are the properties of PP?
- tough
- good fatigue resistance
- good chemical resistance
- available in translucent
- safe working temp 100
What are the uses of PP?
- rope
- folders
- folio cases
- food containers
- medical equipment
What are the properties of HIPS?
- hard
- rigid
- tough
- available in translucent
- safe working temp 70
What are the uses of HIPS?
- yoghurt pots
- refrigerator linings
- single-use drink cups
- toilet seats
- instrument control knobs
What are the properties of ABS?
- tough
- hard
- available in opaque
- safe working temp 80
What are the uses of ABS?
- telephone handsets
- rigid luggage
- domestic appliances
- handles
- computer housings
- remote control casings
- calculator casings
What are the properties of PMMA?
- tough
- hard
- good chemical resistance
- available in translucent
- safe working temp 95
What are the uses of PMMA?
- car light casings
- CNC laser cut items
- lighting units
- lighting covers
- baths
What are the properties of nylon?
- tough
- corrosion resistant
- good temperature resistance
- low coefficient of friction
- safe working temp 150
What are the uses of nylon?
- bearings
- gears
- curtain rails
- textiles
- boil-in-the-bag food packaging
- car engine manifolds
- cable ties
What are the properties of uPVC?
- rigid
- opaque
- tough
- hard
- good weathering resistance
- good chemical resistance
- safe working temp 95
What are the uses of uPVC?
- window frames
- external doors
- guttering and downpipes for buildings
- water service pipes
- bank cards
What are the properties of PVC?
- tough
- flexible
- good weathering resistance
- good chemical resistance
- available in translucent
- safe working temp 95
What are the uses of PVC?
- hose pipes
- cable insulation
- medical grade tubing
- inflatable products
- imitation leather
- seat coverings
What are thermoset polymers?
(examples)
- urea formaldehyde (UF)
- melamine formaldehyde (MF)
- polyester resin
- epoxy resin
What are the properties of UF?
- hard
- heat resistant
- good electrical insulator
- brittle
- safe working temp 80
What are the uses of UF?
- electrical fittings
- adhesives
What are the properties of MF?
- hard
- opaque
- tough
- heat resistant
- food safe
- chemical resistant
- safe working temp 130
What are the uses of MF?
- decorative laminates
- picnic ware
- buttons
What are the properties of polyester resin?
- rigid
- heat resistant
- chemical resistant
- brittle
- safe working temp 95
What are the uses of polyester resin?
- castings
- used in lay-up process for GRP for boat hulls
- car parts
- chair seats
What are the properties of epoxy resin?
- rigid
- clear
- hard
- tough
- chemical resistant
- safe working temp 80 - 200
What are the uses of epoxy resin?
- adhesives
- surface coatings
- encapsulation of electrical components
- cardiac pacemakers
- aerospace applications
What are elastomers?
(examples)
- natural rubber (polyisoprene)
- butadiene rubber (BR)
- neoprene (polychloroprene rubber)
- silicone
What are the properties of natural rubber?
- high tensile strength
- low elongation
- good hardness
- tough
- electrical insulator
- good cold resistance
What are the uses of natural rubber?
- automotive industry such as tyres, tubes, hoses, gaskets, belts
- balloons
- toys
- footwear
What are the properties of BR?
- tough
- excellent wear resistance against friction
- good thermal resistance against friction
- electrical insulator
What are the uses of BR?
- vehicle tyres
- shoe soles
- toys
- conveyor belts
- water and pneumatic hoses
What are the properties of neoprene?
- good thermal resistance
- good toughness
- good oil and chemical resistance
- excellent weather resistance
- good abrasion resistance
- electrical insulator
What are the uses of neoprene?
- wetsuits
- laptop cases
- industrial wire insulation
- automotive applications such as shock absorber seals, hose covers, transmission belts, gaskets, and door seals
What are the properties of silicone?
- good flexibility at low temperatures
- poor abrasion resistance
- good thermal resistance and resistance to temperature extremes
- good weather resistance
- good lubricating qualities
- electrical insulator
What are the uses of silicone?
- flexible ice cube trays
- bakeware
- cooking utensils
- seals for refrigerators
- machinery lubricant
- sealants
- mould making
- medical uses such as lubricants for prosthetics, tubing for drug delivery systems
