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The heat distortion temperature is determined by the following test procedure outlined in ASTM D648. The test specimen is loaded in three-point bending in the edgewise direction. The outer fiber stress used for testing is either 0.455 MPa or 1.82 MPa, and the temperature is increased at 2 °C/min until the specimen deflects 0.25 mm.
HDPE is known for its high strength-to-density ratio. [4] The density of HDPE ranges from 930 to 970 kg/m 3. [5] Although the density of HDPE is only marginally higher than that of low-density polyethylene, HDPE has little branching, giving it stronger intermolecular forces and tensile strength (38 MPa versus 21 MPa) than LDPE. [6]
The high-temperature properties of the polymer are improved, its flow is reduced, and its chemical resistance is enhanced. PEX is used in some potable-water plumbing systems because tubes made of the material can be expanded to fit over a metal nipple and it will slowly return to its original shape, forming a permanent, water-tight connection.
The onset of thermal degradation dictates the maximum temperature at which a polymer can be used. It is an important limitation in how the polymer is manufactured and processed. For instance, polymers become less viscous at higher temperatures which makes injection moulding easier and faster, but thermal degradation places a ceiling temperature ...
HDPE pipe is a type of flexible plastic pipe used to transfer fluids and gases.It is often employed for replacing aging concrete or steel main pipelines.Constructed from the thermoplastic HDPE (high-density polyethylene), it has low permeability and robust molecular bonding, making it suitable for high-pressure pipelines.
Spurred by a low-pressure storm off Canada's Hudson Bay, the game-time temperature read -9 degrees, with incessant wind making it feel like -38 degrees (often cited as -59 degrees under the old ...
The Properties of Polyethylene Crystallized Under the Orientation and Pressure Effects of a Pressure Capillary Viscometer, Journal of Applied Polymer Science vol. 14, pp. 2305–2317 (1970). Kanamoto, On Ultra-High Tensile by Drawing Single Crystal Mats of High Molecular Weight Polyethylene, Polymer Journal vol. 15, No. 4, pp. 327–329 (1983).
With hot wedge welding, the speed of travel is an added parameter as the wedge unit is self-propelled by the rollers. The typical temperature range when welding high-density polyethylene (HDPE) is 220 to 400 °C (428 to 752 °F); the travel speed is typically 0.7 to 4 metres per second (2.3 to 13.1 ft/s). [5]