8-Performance and characteristics of polymers

• Performance characteristics of polymers

  • Stock forms
  • Characteristics of polymers
• Granules


  Small particles of plastic
• Sheet


  Large flat sections of polymer in varying thicknesses
• Film


  Very thin sheet polymer
• Rods and other extruded forms, tubes, bars


  • Rods and extruded forms can be a specific designed shape such as a curtain rail
  • Bar is solid form, square or round
  • Tube is hollow in cross-section and can be square, rectangular or round
• Foams


  Solid form made by including air or other gases, such as styrofoam from expanded polystyrene
• Powder


  Very fine granule of polymer
• Synthetic polymers


  Made from crude oil, take hundreds of years to degrade
• Self-finishing


  Can be pigmented during the manufacturing process to give colour and therefore require no additional secondary finishing process
• Classifications of polymers


  • Thermoplastic
  • Thermoset polymer
  • Elastomer
• Thermoplastic


  A material that can be reheated and reshaped repeatedly, allowing it to be recycled after its initial use
• Thermoset polymer


  A material that, when heated, undergoes a chemical change whereby the molecules form rigid cross-links. They cannot be reheated and reshaped, even at very high temperatures
• Elastomer


  A material that, at room temperature, can be deformed under pressure and then, upon release of the pressure, will return to its original shape
• Low-density polyethylene (LDPE)


  • Very tough, good chemical resistance, weather proof, available in translucent, low level of rigidity
  • Safe working temperature 65°C
  • uses: food wrap film, toys, carrier bags, bin bags
• High-density polyethylene (HDPE)


  • Available in translucent, weather proof, tough, good chemical resistance
  • Safe working temperature 65°C
  • uses: toys, bowls, buckets, carrier bags
• Polypropylene (PP)


  • Available in translucent, good chemical resistance, tough, good fatigue resistance (hinge property)
  • Safe working temperature 100°C
  • uses: rope, folders, food containers
• High-impact polystyrene (HIPS)


  • Hard, rigid, available in translucent, tough
  • Safe working temperature 70°C
  • uses: yogurt pots, toilet seats
• Acrylonitrile butadiene styrene (ABS)


  • Tough, hard, available in opaque
  • Safe working temperature 80°C
  • uses: rigid luggage, remote control casings
• Polymethylmethacrylate (PMMA)


  • Tough, hard, good chemical resistance, available in translucent
  • Safe working temperature 75°C
  • uses: car light casings,baths
• Nylon


  • Tough, corrosion resistant, good temperature resistance, low coefficient of friction
  • Safe working temperature 150°C
  • uses: curtain rails, textiles, gears
• Rigid polyvinyl chloride (uPVC)


  • Rigid, opaque, tough, hard, good weathering resistance, good chemical resistance
  • Safe working temperature 95°C
  • uses: window frames, bank card
• Flexible polyvinyl chloride (PVC)

  • Available in translucent, tough, flexible, good weathering resistance, good chemical resistance
  • Safe working temperature 95°C
  • hose pipes, cable insulation
• Urea formaldehyde (UF)


  • Hard, heat resistant, good electrical insulator, brittle
  • Safe working temperature 80°C
  • uses: adhesives, electrical fittings
• Melamine formaldehyde (MF)


  • Hard, opaque, tough, heat resistant, food safe, chemical resistant
  • Safe working temperature 130°C
  • uses: buttons, picnic wear
• Polyester resin


  • Rigid, heat resistant, chemical resistant, brittle
  • Safe working temperature 95°C
  • uses: castings
• Epoxy resin


  • Rigid, clear, hard, tough, chemical resistant
  • Safe working temperature 80-200°C
  • uses: surfsce coatings, adhesive
• Natural rubber (polyisoprene)


  • High tensile strength, low elongation, good hardness, tough, electrical insulator, good cold resistance
  • uses: tyres,toys, footwear
• Butadiene rubber (BR)


  • Tough, excellent wear resistance against friction, good thermal resistance against friction, electrical insulator
  • uses: vehicle tyres,toys
• Neoprene (polychloroprene rubber)


  • Good thermal resistance, toughness, good oil and chemical resistance, excellent weather resistance, good abrasion resistance and electrical insulator
  • uses: wetsuits, laptop cases
• 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
  • uses: flexible ice cube trays,cooking utensiles