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