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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]
The high molecular weight makes it a very tough material, but results in less efficient packing of the chains into the crystal structure as evidenced by densities of less than high-density polyethylene (for example, 0.930–0.935 g/cm 3). UHMWPE can be made through any catalyst technology, although Ziegler catalysts are most common.
Low-density polyethylene (LDPE), on the other hand, has significant numbers of both long and short branches, is relatively flexible, and is used in applications such as plastic films. Dendrimer and dendron. Dendrimers are a special case of branched polymer where every monomer unit is also a branch point.
These molecules are several orders of magnitude longer than those of familiar high-density polyethylene (HDPE) due to a synthesis process based on metallocene catalysts, resulting in UHMWPE molecules typically having 100,000 to 250,000 monomer units per molecule each compared to HDPE's 700 to 1,800 monomers.
[17] Piping systems for the conveyance of water, chemicals or gases are commonly produced in Polypropylene, and to a much greater extent Polyethylene. Piping systems in high-density Polyethylene (HDPE, PE100, PE80) are fast becoming the most commonly used drinking water, waste water and natural gas distribution piping systems in the world.
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.
LDPE has SPI resin ID code 4 Schematic of LDPE branching structure. Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene.It was the first grade of polyethylene, produced in 1933 by John C. Swallow and M.W Perrin who were working for Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. [1]
Polyethylenimine (PEI) or polyaziridine is a polymer with repeating units composed of the amine group and two carbon aliphatic CH 2 CH 2 spacers. Linear polyethyleneimines contain all secondary amines, in contrast to branched PEIs which contain primary, secondary and tertiary amino groups.