Apr 11 2003
Background
Polycarbonate is a crystal clear and colourless, amorphous engineering thermoplastic notable for its high impact resistance (which remains high down to –40°C).
It has reasonably good temperature resistance, good dimensional stability and low creep but somewhat limited chemical resistance and is prone to environmental stress cracking. Polycarbonate also has poor fatigue and wear properties.
Applications
Applications of Polycarbonate include glazing, safety shields, lenses, casings and housings, light fittings, kitchenware (microwaveable), medical apparatus (sterilisable) and CD's (the discs).
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CD's are one of many applications that use Polycarbonate due to its crystal clear and colourless appearance. Image Credit: ShutterStock/ ALEXEY Filatov
Key Properties
The key properties of Polycarbonate are tabulated below.
Table 1. Key properties
| Chemical Resistance |
| Acids - concentrated |
Fair |
| Acids - dilute |
Good |
| Alcohols |
Good |
| Alkalis |
Poor |
| Aromatic hydrocarbons |
Poor |
| Greases and Oils |
Good |
| Halogens |
Poor |
| Ketones |
Poor |
| Electrical Properties |
| Dielectric constant @ 1 MHz |
2.9 |
| Dielectric strength ( kV.mm-1 ) |
15-67 |
| Dissipation factor @ 1 MHz |
0.01 |
| Surface resistivity ( ohm/sq ) |
1015 |
| Volume resistivity ( ohm.cm ) |
1014-1016 |
| Mechanical Properties |
Abrasive resistance - ASTM D1044
( mg/1000 cycles ) |
10-15 |
| Coefficient of friction |
0.31 |
| Compressive strength ( MPa ) |
>80 |
| Elongation at break ( % ) |
100-150 |
| Hardness - Rockwell |
M70 |
| Izod impact strength ( J.m-1 ) |
600-850 |
| Poisson's ratio |
0.37 |
| Tensile modulus ( GPa ) |
2.3-2.4 |
| Tensile strength ( MPa ) |
55-75 |
| Physical Properties |
| Abbe number |
34.0 |
| Density ( g.cm-3 ) |
1.2 |
| Flammability |
V0-V2 |
| Limiting oxygen index ( % ) |
25-27 |
| Refractive index |
1.584-6 |
| Resistance to Ultra-violet |
Fair |
| Water absorption - equilibrium ( % ) |
0.35 |
| Water absorption - over 24 hours ( % ) |
0.1 |
| Thermal Properties |
Coefficient of thermal expansion
( x10-6 K-1 ) |
66-70 |
| Heat-deflection temperature - 0.45 MPa (°C) |
140 |
| Heat-deflection temperature - 1.8 MPa (°C) |
128-138 |
| Lower working temperature (°C) |
-135 |
| Specific heat ( kJ.kg-1.K-1 ) |
ca.1.2 |
Thermal conductivity @ 23 °C
( W.m-1.K-1 ) |
0.19-0.22 |
| Upper working temperature (°C) |
115-130 |
| Properties Polycarbonate Film |
| Property |
|
Value |
| Dielectric Strength @ 25 µm thick |
kV mm-1 |
350 @ 40&m |
| Dissipation Factor @ 1 MHz |
|
0.010 |
| Extension to break - Longitudinal |
% |
~100 - grade N, DE1,
~40 - grade KG |
| Extension to break - Transverse |
% |
~100 - grade N, DE1,
>100 - grade KG |
| Heat-sealing Temperature |
C |
204-221 |
| Initial Tear Strength |
g.µm-1 |
12-29 |
| Permeability to Carbon Dioxide @ 25 °C |
x10-13 cm3. cm.cm-2.s-1.Pa-1 |
4.8 |
| Permeability to Hydrogen @ 25 °C |
x10-13.cm3.cm.cm-2.s-1.Pa-1 |
9.0 |
| Permeability to Nitrogen @ 25 °C |
x10-13 cm3.cm.cm-2.s-1.Pa-1 |
0.23 |
| Permeability to Oxygen @ 25 °C |
x10-13 cm3.cm.cm-2.s-1.Pa-1 |
1.05 |
| Permeability to Water @ 25 °C |
x10-13 cm3.cm.cm-2.s-1.Pa-1 |
1050 |
| Tensile strength - Longitudinal |
MPa |
>80 - grade N, DE1,
>220 - grade KG |
| Tensile strength - Transverse |
MPa |
>80 |
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