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Amorphous Polymer
 Polymer
chains with branches or irregular pendant groups cannot
pack together regularly enough to form crystals. These
polymers are said to be amorphous. A two-dimensional
schematic of an amorphous polymer is shown at the right.
Amorphous regions of a polymer are made up of a randomly
coiled and entangled chains. They have been compared to
a bucket containing a large number of entangled worms -
each one 20-feet long and of 1/4-inch thickness1. The
worms are so tangled that an entire worm cannot slide
past the others, but small portions of the worms can
twist around within the mass.
Amorphous polymers are softer, have lower melting
points, and are penetrated more by solvents than are
their crystalline counterparts.
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| Overview |
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| Pro's |
Cons |
- Good Clarity
- High Impact
- Good Low Temperature Performance
- Good Surface Appearance
- High Stiffness
- Little Shrinkage
- No Warpage
- Wide Processing Window
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- Poor Chemical Resistance
- Poor high Temperature Performance
- Flows Under its Own Weight Above Tg
- Poor Creep
- Little Memory (Not For Living Hinges)
- Solvent Bondable
- Easily Painted or Plated
- Good Cooling Needed
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Polymer |
Advantages |
Drawbacks |
Some Typical Applications |
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PAI |
High heat, High
wear |
Very hard to
process |
Bearings,
Aerospace |
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PEI |
Impact, Heat,
Sterilization, Microwave |
Benzene,
Gasoline |
Engine
internals |
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PSU |
Alcohol, Salt,
Hot water, Plumbing |
Benzene,
Gasoline |
Hot water pipes |
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PUR |
Gasoline,
Acids, Oil, Plating |
Boiling water |
Fuel bowls |
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PPO |
Hot water,
Solvent bondable, Easy FR |
Oil, Gasoline,
Grease |
Pump housings |
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PC |
Impact,
Stiffness, Optical |
Oil, Gasoline,
Grease, Chemicals |
Safety glass
lenses |
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ASA |
Weatherable,
Oil, Grease, Salt |
Benzene,
Alcohol |
Auto trim,
Signage |
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PMMA |
Weatherable,
Clarity, Lenses, Scratch resistance |
Low temperature
impact, Dishwater |
Signs,
Reflectors |
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COPOLYESTER |
Some oil, Gas,
Detergents, Scratch resistance |
Temperatures,
Inadequate cooling |
Shampoo
equipment |
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SMMA |
Practical
Toughness, Sterilization |
High impact
strength |
Medical, Vacuum
equipment |
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ABS |
Impact,
Stiffness, Economical |
Oil, Gasoline,
Grease, Esters |
Housings, Auto
interior |
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SAN |
Clarity,
Stiffness, Improved chemical resistance |
Many chemicals,
Impact |
Tumblers,
Cosmetics |
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PVC |
Weatherability,
Good impact, Water
resistance |
Environmental,
Corrosion |
Outdoor drains,
Pools |
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PS/HIPS |
Economical,
Impact, Stiffness |
Moderate
Chemicals |
Disposable
housings |
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