Plastic Material Properties

Thermoplastics
1. Formed by chain-growth polymerisation
2. Solid at room temperature
3. Melted or softened by heating
4. placed in a mould or shaping device and are then cooled to give desired shape
5. High strength and stiffness
  1. Can be reinforced
6. Holds mechanical properties up to around 80 degrees
7. Good impact resistance
8. Dimensional stability within temperature range
9. Good water and chemical resistance
10. Easy to shape to desired forms
11. Extrusion - continuous 2D shaping process used for wires, films and pipes
12. Injection Moulding - discontinuous process capable of generating complex 3D shapes
13. Extrusion Blow Moulding - for small and medium sized containers and bottles
14. Rotational Moulding- used for hollow parts manufactured at low production size
Thermosets
1. Formed by step-growth polymerisation
2. Can be liquid or solid at room temperature
3. Cannot be reshaped by heating
4. Placed in a mould and then heated to harden (cure) then the chemical reaction occurs
5. Phenolics noted for high hardness and stiffness
  1. Can replace hard materials like Ivory
6. Amino plastics are hard and brittle
  1. Can be used as adhesives or countertops
7. Epoxides are stiff and strong
  1. Can be used as adhesives for composite materials
8. Polyurethanes can be designed with different strength vs flexibility
  1. Good abrasion resistance
9. As well as the forming operation this requires reactive processing of the polymer with a curing agent, this can be done as high or low pressure moulding
  1. Compression Moulding - polymer mixed with the curing agent is pressed at high pressure into a closed mould

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Plastic Material Properties

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	Created by joeawilson over 8 years ago