Cards (43)

  • Toughness is the ability to withstand a sudden impact
  • Hardness is the ability of a material to withstand scratching, cutting and abrasion (wear)
  • Polymers are produced industrially through a process known as polymerisation
  • Synthetic polymers are made from hydrocarbons
  • Composition of the polymers can be adjusted to create different properties for specific purposes
  • Two types of polymers: thermosetting and thermoforming
  • Thermosetting polymers cannot be recycled
  • Thermosetting polymers form cross-links between chains
  • (ER) Epoxy Resin
    • Good electrical insulator
    • hard
    • brittle unless reinforced
    • resists chemicals well
    USED FOR
    adhesives
    casting
    encapsulation (eg: laminating paper)
  • (PF) Phenol-Formaldehyde
    • Hard
    • Strong
    • heat and chemical resistant
    • good electrical insulator
    • limited colours available
    USED FOR
    Bowling balls
    Saucepan Handles
  • (MF) Melamine-Formaldehyde
    • Stiff
    • hard
    • strong
    • resists some chemicals and stains
    USED FOR
    Laminates for work surfaces
    Hawker Centre tableware
    Electrical insulation
  • (PR) Polyester Resin
    • Brittle but becomes tough when laminated with glass fibre
    • good compressive and tensile strength
    • hard
    • UV resistant
    USED FOR
    GRP boats
    Car Body Panels
  • (UF) Urea-Formaldehyde
    • Stiff
    • hard
    • strong
    • brittle
    • good electrical insulator
    USED FOR
    Adhesives (MDF)
    Electrical Fittings
  • ER = Epoxy Resin
  • PR = Polyester Resin
  • MF = Melamine Formaldehyde
  • PF = Phenol Formaldehyde
  • UF = Urea Formaldehyde
  • (7) = Acrylic
  • (6) = High Impact Polystyrene HIPS
  • (3) = Polyvinyl Chloride PVC
  • (1) = Polyethylene Terephthalate PET
  • (5) = Polypropylene PP
  • (4) = Low Density Polyethylene LDPE
  • Heating weakens the join and softens the polymer, which means it can be reshaped by heating. As the plastic cools, it hardens to a permanent shape
  • Polypropylene - Fatigue and moisture resistance
  • Polyethylene Terephthalate - High Tensile Strength, food safe
  • High-Density Polythene - Excellent Chemical Resistance, Able to be Sterilised
  • Polyvinyl Chloride - Can be rigid or flexible, Hard (resistant to scratching)
  • Polyvinyl Chloride - think of vinyl record
  • High Impact Polystyrene - Fusibility (easy to mould), Lightweight, resistance to moisture
  • Low Density Polythene - used for toothpaste container, ketchup bottles
  • PET used for food packaging, fibres for clothing and plastic waterbottles
  • PP (most common plastic) used for chairs, toys and bottle caps
  • HDPE used for buckets, tubing and washing up bowls
  • PVC used for Water pipes, raincoats and window frames
  • PPMA used for Signs, Aircraft canopies and baths
  • HIPS used for yogurt pots, refrigerator and vacuum-formed packaging
  • Combining polymers with other materials can reinforce them (make them stronger) by combining the properties of both materials
  • usually, thermosetting polymers (typically epoxy) are used because they come in a liquid state and can impregnate and form around the second material