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fn:Duc Minh Ngo
n:Ngo;Duc Minh
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CH2, mol.wt.=14

Cristalinity

        Low Linear: 60%

        High Density: up to 95%

Pyrolysis: melts and becomes transparent; in the absence of air is stable up to 300 deg. C.

                  Cross-linked types do not melt.

Specific gravity: Low density 0.915 to 0.94

                  High density 0.94 to 0.97

Refractive index: 1.51 to 1.52

Moisture relations: beying paraffins, polyethylenes are resistant to water; increase in weight

                    after 1 year less than 0.2%.

Thermal properties

Specific heat 0.55 at 20 deg. C, rising to 0.7 at 120 deg. C.

Coeficient of linear expansion: 0.00017 to 0.00022 for low density

                                0.00013 to 0.00020 for high density

Melting point(loss of cristalinity): 109 to 125 deg. C for low density

                                     130 to 135 deg. C for high density

Electrical properties

Resistivity 1017 to 1019  (ohm cm)

Dielectric strength 20 to 160 (kV/mm)

Dielectric constant 2.28

Mechanical properties

Elastic modulus 15.4 to 125.0 (daN/mm2)

Strain rate(mm/min)                          50           500

Yield strength(daN/mm2)                      2.28        2.36

Ultimate tensile strength(daN/mm2)           3.43        1.33

Hardness: low density, 50-60

          high density, 65-70

Impact:   low density, 0.92

          high density, 0.96