LDPE is defined by a density range of 0.910–0.940 g/cm3. It is not reactive at room temperatures, except by strong oxidizing agents, and some solvents cause swelling. It can withstand temperatures of 80 °C continuously and 95 °C for a short time. Made in translucent or opaque variations, it is quite flexible and tough.
LDPE has more branching than HDPE, so its intermolecular forces are weaker, its tensile strength is lower, and its resilience is higher. Also, because its molecules are less tightly packed and less crystalline due to the side branches, its density is lower.
PTFE is a thermoplastic polymer, which is a white solid at room temperature, with a density of about 2200 kg/m3. According to DuPont, its melting point is 600 K (327 °C; 620 °F).[19] It maintains high strength, toughness and self-lubrication at low temperatures down to 5 K (−268.15 °C; −450.67 °F), and good flexibility at temperatures above 194 K (−79 °C; −110 °F). PTFE gains its properties from the aggregate effect of carbon-fluorine bonds, as do all fluorocarbons. The only chemicals known to affect these carbon-fluorine bonds are highly reactive metals like the alkali metals, and at higher temperatures also such metals as aluminium and magnesium, and fluorinating agents such as xenon difluoride and cobalt(III) fluoride.
Material Applications:
PTFE:Cabling solutions;Non lubricated bearings;O-rings;Seals;Capacitors;Semiconductor manufacturing;High temperature electrical parts;Gaskets;Valve components.
LDPE:Trays and general purpose containers;Corrosion-resistant work surfaces;Parts of computer hardware, such as hard disk drives, screen cards, and optical disc drives.
Material Properties
PTFE:Excellent dielectric properties;Inertness to most chemicals;High heat and chemical resistance;Very low coeffiecient of friction;Excellent radiation resistance;Zero moisture absorption;Relatively insensitive to power frequency;Machinability.
LDPE:Non-reactive at room temperatures;Can withstand temperatures of 80 °C continuously;Machinability.
