Polythene is a polymer that is constructed out of long strands of ethylene. It is one of the most commonly used plastics in the world as it is used in packaging and plastic bags. Polythene is most commonly classified by density; the three most common varieties are high-density polythene (HDPE), medium density polythene (MDPE) and low-density polythene (LDPE). This results in separate sets of electrical properties.
HDPE has a very high resistivity. According to Plastics International, its volume resistivity is rated at greater than 10^15 ohm/square, and its surface resistivity is also greater than 10^15 ohm-cm. This makes it act as an insulator more than a conductor; in comparison, copper yields a surface resistivity of 1.68 x 10^-8 ohm-m. HDPE has a dielectric strength of 19.7 kV/mm.
MDPE is the least common of the three types of polythene. It has a dielectric strength of 27 MV/m, according to the AZoM website. Like HDPE, MDPE has a volume resistivity of 10^15 ohm-cm and a surface resistivity of 10^15 ohm/square, making it just as poor a conductor as HDPE.
LDPE is most commonly found in thin plastic sheeting used in packaging or plastic bags. When the polymer was first discovered, LDPE was what was created; it was a thin, waxy film. It has the same dielectric strength as MDPE at 27 MV/m, and resistivity of greater than 10^15 ohm-cm.