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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]
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 .
Polyethylene was first synthesized by the German chemist Hans von Pechmann, who prepared it by accident in 1898 while investigating diazomethane. [12] [a] [13] [b] When his colleagues Eugen Bamberger and Friedrich Tschirner characterized the white, waxy substance that he had created, they recognized that it contained long −CH 2 − chains and termed it polymethylene.
Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) is a subset of the thermoplastic polyethylene.Also known as high-modulus polyethylene (HMPE), it has extremely long chains, with a molecular mass usually between 3.5 and 7.5 million amu. [1]
The glue squeezed out of the heated nozzle is initially hot enough to burn and even blister skin. The glue is sticky when hot, and solidifies in a few seconds to one minute. Hot-melt adhesives can also be applied by dipping or spraying, and are popular with hobbyists and crafters both for affixing and as an inexpensive alternative to resin casting.
Updated at 9:49 a.m. BOCA CHICA — Starship S28 and Super Heavy B10 lifted off from Boca Chica at 8:25 a.m. Thursday for SpaceX's third Starship orbital flight attempt, after being granted ...
The rocket took off from its launchpad in Boca Chica at about 9:25 a.m. ET, clearing several critical hurdles along its hourlong journey. "Starship reached orbital velocity!" SpaceX founder Elon ...
Boca Juniors vs Fluminense kicks off at 8pm GMT on Saturday 4 November 2023. Where can I watch it in the UK? The match will be broadcast live and free on BBC Three in the UK.