Polyethylene Plastics Testing

Polyethylene plastics (polyethene or polymethylene) is the most widely used plastic in the world, carrying an annual production rate of approximately 80 million metric tons. Its primary use is in various packaging products such as plastic shopping bags and plastic food containers. Polyethylene is a thermoplastic polymer consisting of long chains of the monomer ethylene and is abbreviated as PE. Polyethylene consists of the two chemical elements hydrogen and carbon. PE is created through the polymerization of ethene and is classified into several categories based primarily on its density and branching of its molecular structure and weight.

See typical properties of polyethylene listed below.

PROPERTIES ASTM TEST METHOD LOW DENSITY LINEAR LOW DENSITY HIGH DENSITY

Melt flow (g/10 min)

D1238

0.25-35

0.15-50

0.25-50

Melting temperature, °C

 

118-160

76-232

138

Processing temp. range, °C      Injection

 

149-232

176-260

176-260

Extrusion

 

121-300

249-293

149-300

Molding pressure range, 103 psi

 

5-15

5-15

 

Mold (linear) shrinkage, in/in

D955

0.002-0.05

0.015-0.02

 

Tensile strength at break, psi

D638

1080-2200

1100-5200

1400-5600

Elongation at break, %

D638

4-650

1-1000

1-1000

Tensile yield strength, psi

D638

1100-2700

800-3400

3200-5200

Compressive strength (rupture or yield) psi

D695

 

 

 

Flexural strength (rupture or yield) psi

D790

 

2600-72500

7000

Tensile modulus, 103 psi

D638

13-70

21-81

150-195

Compressive modulus, 103 psi

D695

 

 

 

Flexural modulus, 103 psi        23°C

D790

18-56

27-100

115-260

Izod Impact, ft·lb/in of notch

D256A

 

0.34-10

0.5-4

Hardness                         Rockwell

D785

R41

 

 

Shore/ Barcol

 

D2240

D2583

Shore A55-98

Shore D32-98

Shore A72

Shore D26-68

Shore D60-70

Coef. of linear thermal expansion, 10-6 in/in/°C

D696

120-200

65-360

150-155

Deflection temperature °C     264 psi

D648

38-49

32-43

42-50

66 psi

D648

38-71

22-76

65-115

Specific gravity

D792

0.4-2.04

0.9-2.1

0.96-0.97

Water Absorption, %          24 hrs.

D570

0.01-0.1

 

 

Dielectric strength short time, v/mil

D149

500-800

500-550

700

Polyhedron Laboratories specializes in performing the tests listed in the above table.