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Polyethylene Specifications
GENERAL DESCRIPTION
Polyethylenes are semi-crystalline materials with excellent
chemical resistance, good fatigue and wear resistance, and a wide range of
properties (due to differences in length of the polymer chain.)
Polyethylenes are easy to distinguish from other plastics because they float
in water.
GENERAL PROPERTIES OF POLYETHYLENES
Polyethylenes provide good resistance to organic solvents,
degreasing agents and electrolytic attack. They have a higher impact
strength, but lower working temperatures and tensile strengths than
polypropylene. They are light in weight, resistant to staining, and have low
moisture absorption rates.
POLYETHYLENE GRADES
Low Density Polyethylene (LDPE)
This extruded material offers good corrosion resistance and low moisture
permeability. It can be used in applications where corrosion resistance is
important, but stiffness, high temperatures, and structural strength are
not. A highly flexible product, LDPE is used widely in orthopaedic products,
or where mobility without stress fatigue is desired. LDPE is also frequently
used in comsumer packaging, bags, bottles, and liners.
High Density Polyethylene (HDPE)
Representing the largest portion of the polyethylene applications, HDPE
offers excellent impact resistance, light weight, low moisture absorption,
and high tensile strength. HDPE is also non-toxic and non-staining and meets
FDA and USDA certification for food processing.
Ultra High Molecular Weight Polyethylene (UHMW PE)
Light weight (1/8 the weight of mild steel), high in tensile strength, and
as simple to machine as wood, UHMW PE is the ideal material for many wear
parts in machinery and equipment as well as a superb lining in material
handling systems and storage containers. UHMW PE is self-lubricating,
shatter resistant, long-wearing, abrasion and corrosion resistant. It meets
FDA and USDA acceptance for food and pharmaceutical equipment and is a good
performer in applications up to 180 °F (82 °C) or when periodically cleaned
with live steam or boiling water to sterilize.
( see also
Lennite® Conductive and
Tivar® 1000 AntiStatic UHMW Specifications )
( see also
QuickSilver® Liners )
| TYPICAL PROPERTIES of POLYETHYLENE |
| ASTM or UL test |
Property |
LDPE |
HDPE |
UHMW |
| PHYSICAL |
| D792 |
Density (lb/in³)
(g/cm³) |
0.033
0.92 |
0.035
0.95 |
0.034
0.93 |
| D570 |
Water Absorption, 24 hrs (%) |
<0.01 |
0 |
0 |
| MECHANICAL |
| D638 |
Tensile Strength (psi) |
1,800-2,200 |
4,600 |
3,100 |
| D638 |
Tensile Modulus (psi) |
- |
- |
125,000 |
| D638 |
Tensile Elongation at Yield (%) |
600 |
900 |
- |
| D790 |
Flexural Strength (psi) |
- |
- |
- |
| D790 |
Flexural Modulus (psi) |
- |
200,000 |
125,000 |
| D695 |
Compressive Strength (psi) |
- |
- |
2,000 |
| D695 |
Compressive Modulus (psi) |
- |
- |
- |
| D785 |
Hardness, Shore D |
D41-D50 |
D69 |
D62-D66 |
| D256 |
IZOD Notched Impact (ft-lb/in) |
No Break |
3 |
No Break |
| THERMAL |
| D696 |
Coefficient of Linear Thermal Expansion
(x 10 -5 in./in./°F) |
3 |
6 |
11 |
| D648 |
Heat Deflection Temp (°F / °C)
at 66 psi
at 264 psi |
120 / 48
105 / 36 |
170 / 76
150 / 40 |
203 / 95
180 / 82 |
| D3418 |
Approx. Melting Temperature (°F / °C) |
230 / 110 |
260 / 125 |
280 / 138 |
| - |
Max Operating Temp (°F / °C) |
160 / 71 |
180 / 82 |
180 / 82 |
| C177 |
Thermal Conductivity
(BTU-in/ft²-hr-°F)
(x 10 -4 cal/cm-sec-°C) |
-
-
|
-
-
|
2.92
10.06
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| UL94 |
Flammability Rating |
n.r. |
n.r. |
H-B |
| ELECTRICAL |
| D149 |
Dielectric Strength (V/mil) short time, 1/8" thick |
460-700 |
450-500 |
900 |
| D150 |
Dielectric Constant at 1 kHz |
2.25-2.30 |
2.30-2.35 |
2.30-2.35 |
| D150 |
Dissipation Factor at 1 kHz |
0.0002 |
0.0002 |
0.0002 |
| D257 |
Volume Resistivity (ohm-cm) at 50% RH |
10 15 |
10 15 |
10 18 |
| D495 |
Arc Resistance (sec) |
135-160 |
200-250 |
250-350 |
NOTE: The information contained herein are typical values intended
for reference and comparison purposes only. They should NOT be used as a
basis for design specifications or quality control. Contact us for
manufacturers' complete material property datasheets.
All values at 73°F (23°C) unless otherwise noted.
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