8) Performance characteristics of polymers

Question 1

State the 6 stock forms of polymers

Answer 1

1) Granules: small particles of plastic
2) Sheet: Large, flat sections of polymer in varying thicknesses
3) Film: Very thin sheet polymer
4) Extruded forms (e.g. rods, tubes, bars…)
5) Foam: Solid including injected air or other gasses
6) Powder: Very fine granules of polymers

Question 2

Define synthetic polymers:

Answer 2

Made from crude oil, takes hundreds of years to degrade. Non-renewable

Question 3

Polymers are ‘self finishing’. Explain this term

Answer 3

Can be pigmented during the manufacturing process to give colour and therefore requires no additional secondary finishing process

Question 4

State the 7 categories of thermoforming polymers

Answer 4

1) PET (Polyethylene terephthalate)
2) HDPE (High-density polyethylene)
3) PVC/V (Polyvinyl chloride)
4) LDPE (Low-density polyethylene)
5) PP (Polypropylene)
6) PS (Polystyrene)
7) Others

Question 5

Give three thermosetting polymers, their properties and uses

Answer 5

UF = Hard, heat resistant, good electrical insulator, used for electrical fittings
MF = Hard, opaque, tough, heat&chemical resistant, used for laminates
Epoxy resin = Rigid, clear, hard, tough, chemical resistant, used for adhesives

Question 6

Give three elastomers, their properties and uses

Answer 6

Silicone = Good flexibility at low temperatures, electrical insulator and weather resistance. Used fr flexible ice trays and lubricant/sealants

Natural rubber (polyisoprene) = HIgh tensile strength, low elongation, good hardness. Used in tires, tubes, footwear, balloons

Neoprene = Good thermal resistance, tough, electrical insulator. Used for wetsuits, laptop cases, door seals