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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.
Polymer engineering is generally an engineering field that designs, analyses, and modifies polymer materials. Polymer engineering covers aspects of the petrochemical industry, polymerization, structure and characterization of polymers, properties of polymers, compounding and processing of polymers and description of major polymers, structure property relations and applications.
High-density polyethylene (HDPE) has a very low degree of branching, is relatively stiff, and is used in applications such as bullet-proof vests. 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 ...
Polyethylene (polyethene, polythene, PE) is a family of similar materials categorized according to their density and molecular structure. It is also known as poly and is obtained by the addition polymerisation of ethylene. It may be of low density or high density depending upon the process used in its manufacturing.
Most polyolefin are made by treating the monomer with metal-containing catalysts. The reaction is highly exothermic. Traditionally, Ziegler-Natta catalysts are used. Named after the Nobelists Karl Ziegler and Giulio Natta, these catalysts are prepared by treating titanium chlorides with organoaluminium compounds, such as triethylaluminium.
The density of such boundaries is lower in polymers with very low crystallinity (amorphous polymer) or very high degree of crystalline polymers, consequentially, the transparency is higher. [5] For example, atactic polypropylene is usually amorphous and transparent while syndiotactic polypropylene, which has crystallinity ~50%, is opaque. [ 30 ]
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.