Polymers

• 4 main polymer categories

  • thermoplastic - can be reheated and reformed
  • thermosetting - cannot be reheated and recycled
  • elastomers - soft and flexible with elastic properties
  • biopolymers - biodegradable plastics
• polymers are made up of long chain of molecules containing carbon, hydrogen and oxygen
• synthetic polymers are gained through a process of thermal cracking as they are derived from fossil fuels
• properties of polymers


  • good electrical and thermal conductors
  • good strength to weight ratio
  • good chemical resistance
  • low melting temperatures
  • lightweight
  • self coloured, opaque or transparent and self-finishing
  • hygienic and water resistant
• thermoplastic polymers can be reheated and remoulded repeatedly meaning they can be recycled
• thermoplastics

  • polyethylene terephthalate (PET)
  • low density polyethylene (LDPE)
  • high density polyethylene (HDPE)
  • polypropylene (PP)
  • high impact polystyrene (HIPS)
  • polymethyl-methacrylate (PMMA)
  • polyamide (nylon)
  • acrylonitrile butadiene styrene (ABS)
  • rigid polyvinyl chloride (ABS)
  • flexible polyvinyl chloride (PVC)
• thermoplastics and their properties


  • PET - clear, flexible, tough, lightweight - water bottles
  • LDPE - tough, chemical resistant, weatherproof - carrier bags
  • HDPE - weatherproof, tough, chemical resistant - buckets
  • PP - chemical resistant, fatigue resistant - plastic chairs
  • HIPS - hard, rigid, tough - yoghurt pots
  • PMMA - tough, hard, transparent or translucent - car headlights
  • Nylon - low friction, tough, chemical resistant - hair brushes
  • ABS - extremely tough, hard, heat resistant - electrical casing
  • PVC - tough, flexible, chemical resistant - hose pipes
• thermosetting polymers are polymers that cannot be reheated or reshaped this means they cannot be recycled but at beneficial when they need to be a good effective thermal or electrical insulator
• thermosetting polymers and their properties


  • urea formaldehyde - hard, heat resistant, electrical insulator, brittle - electrical fittings
  • melamine formaldehyde - hard, opaque, heat and chemical resistant, food safe - buttons
  • polyester resin - rigid, heat and chemical resistant, brittle - castings
  • epoxy resin - rigid, clear, hard, tough, chemical resistant - adhesives
• elastomers are polymers that have elastic properties that have a quick production time where scraps can be recycled
• elastomers and their properties


  • natural rubber (polyisoprene) - tensile strength, hardness, cold resistance - tyres
  • butadiene rubber (BR) - tough, wear resistance, electrical insulator - shoe soles
  • neoprene (polychloroprene rubber) - thermal resistant, oil resistant, weather resistant - wetsuits
  • silicone - flexible, weather resistant - cooking utensils
• biopolymers are are biodegradable plastics which break down easily due to not being oil based. these plastics are designed to break down in the right conditions as they are derived from renewable sources
• biopolymers and their properties


  • PHAs - stable, break down in soil - film
  • PHBs - stable, break down in soil - packaging
  • oxo-degradable polymers - degrade in oxygen, heat and moisture - food waste bags
  • photo-degradable polymers - degrade in ultra violet light - plastic bags
  • water-soluble polymers - degradable in water, more expensive than oil-based polymers - washing machine and dishwasher tablets
• oil based polymers are not a sustainable or renewable source of materials. polymers that are made from renewable materials (biopolymers) are a better source as they can continuously be made naturally and recycled in an environmentally friendly way