General Properties
Short Name:
Name:
PE-HD
Polyethylene High Density
PE-HD has a structure with relatively little branching and therefore high density (typically between 0.94 g/cm3 and 0.96 g/cm3).
PE-HD is produced by a low-pressure polmyerization method.
Structural Formula
Properties
| Glass Transition Temperature | -130 to - 100°C |
|---|---|
| Melting Temperature | 125 to 135°C |
| Melting Enthalpy | 293 J/g |
| Decomposition Temperature | 480 to 498°C |
| Young's Modulus | 600 to 1400 MPa |
| Coefficient of Linear Thermal Expansion | 200 to 250 *10-6/K |
| Specific Heat Capacity | 1.8 to 2.7 J/(g*K) |
| Thermal Conductivity | 0.33 to 0.53 W/(m*K) |
| Density | 0.94 to 0.96 g/cm3 |
| Morphology | Semi-crystalline thermoplastic |
| General properties | Better chemical reistance compared to PE-LD, good electrical insulating properties. |
| Processing | Extrusion (foils, profiles), Blow moulding, extrusion (foils, profiles), deep-drawing, injection moulding. |
| Applications | Films (for different applications), packaging for household and industry (e.g. bottles, plastic bags, beverage bottles caps), gas and water pipes, cable lines. |
NETZSCH Measurement
| Instrument | DSC 204 F1 Phoenix® |
| Sample Mass | 10.49 mg |
| Isothermal Phases | 20 min/2 min/20 min |
| Heating/Colling Rates | 10 K/min |
| Crucible | Al, pierced lid |
| Atmosphere | N2 (40 ml/min) |
Evaluation
Although PE-HD belongs to the semi-crystalline thermoplastics, the measurement curves reflect only a melting effect with a peak temperature of approx. 133°C and a melting enthalpy of approx. 201 J/g (2nd heating, red). A glass transition range would have been expected between -130°C and -100°C; however, the specific heat changes are probably too small to be detected in this case. PE-LD and PE-HD differ significantly in their melting temperature. While the low density polyethylene (PE-LD) has a peak temperature of 112°C in the 2nd heating (red), the above example for high-density polyethylene (PE-HD) has a peak temperature of 133°C. Linear low-density polyethylene (PE-LLD) shows a melting effect with characteristic double peak structure , with a main peak temperature (approx. 124°C) that lies between the two previously mentioned values.