High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a polyethylene thermoplastic made from petroleum. This thermoplastic is available in a range of flexibilities depending on the production process. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. Our editors will review what you’ve submitted and determine whether to revise the article. However, not every polyethylene form looks like the above. . A procedure has been developed for the direct atomic force microscopic (AFM) examination of the native structure of high-density polyethylene (HDPE) deformed in an adsorption-active liquid medium (AALM) by the crazing mechanism. HDPE is a thermoplastic and is most often dealt with in the form of a sheet. The density of this polymer ranges from 930 kg/m 3 to 930 kg/m 3. The Florida Department of Transportation (FDOT) recently approved BLUE SEAL ® corrugated HDPE pipe, manufactured by Hancor, Inc., for 100-year service life applications. Products include blow-molded bottles for milk and household cleaners; blow-extruded grocery bags, construction film, and agricultural mulch; and injection-molded pails, caps, appliance housings, and toys. Moreover, HDPE is resistant to a broad range of chemicals. HDPE is now also very commonly used to make body armor, with both soft and hard plate styles being utilized. These processes yield a polymer structure with both long and short branches. High-density polyethylene or HDPE is a commonly used petroleum thermoplastic and the most used of the three polyethylenes for a wide range of applications. Please select which sections you would like to print: Corrections? High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. High-density polyethylene is currently recycled at most recycling centres around the globe, as polyethylene has an easy structure to break down and recycle and is given code #2 as shown in figure 3. It is well-known and liked for being strong, lightweight and easy to shape. High molecular weight high density polyethylene (HMW HDPE) can be defined as a linear homopolymer or copolymer having an average molecular weight in the range of 0.2–1.0 million g/mol. 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). Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... major industrial polymers: Polyethylene (PE). Because the branches prevent the polyethylene molecules from packing closely together in hard, stiff, crystalline arrangements, LDPE is a very flexible material. LLDPE is structurally similar to LDPE. [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 than LDPE. This results in a lower tensile strength and increased ductility. High density polyethylene is made using a low pressure process and Ziegler-Natta or Phillips initiators to control the chain formation, resulting in a highly linear (unbranched) structure. Polyethene, Polythene, PE, LDPE, HDPE, MDPE, LLDPE 1. 2. High-density polyethylene HDPE is manufactured at low temperatures and pressures, using Ziegler-Natta and metallocene catalysts or activated chromium oxide (known as a Phillips catalyst). As the name indicates, HDPE (High Density PolyEthylene) is the polyethylene with the higher density. The density of HDPE can range from 0.93 to 0.97 g, although the density of HDPE is only marginally higher than LDPE (low-density polyethylene). [6] It is also harder and more opaque and can withstand somewhat higher temperatures (120 °C/248 °F for short periods). Because of this, the use of HDPE sheeting has only increased as the years have gone by, again due to the benefits and efficiencies it can bring to nearly any product. Transparent bottles are usually made of other plastics, such as polyethylene terephthalate, HDPE jerrycans resist softening and swelling from aromatic components of fuels. It is sturdy and commonly used in jugs for milk or laundry detergent and bleach bottles. In part for this innovation, Ziegler was awarded the Nobel Prize for Chemistry in 1963. Hancor Pipe Receives 100-Year Service Life Appoval. This property data is a summary of similar materials in the MatWeb database for the category "High Density Polyethylene (HDPE), Ultra High Molecular Weight". The branched form of polyethylene, known as low-density polyethylene (LDPE). HDPE can be translucent or opaque, and the opaque varieties are stronger. The AFM investigation has been carried out in the presence of a liquid medium under conditions preventing deformed films from shrinkage. The polymer chains in HDPE, on the other hand, are more linear. It is an enormously versatile polymer which is suited to a wide range of applications from heavy-duty damp proof membranes for new buildings to light, flexible bags and films. LDPE and HDPE are thermoplastic materials under the family of polyolefins, which are petrochemical-based plastics that include polypropylene (PP) and polyethylene (PE). Linear polyethylene can be produced in ultrahigh-molecular-weight versions, with molecular weights of 3,000,000 to 6,000,000 atomic units, as opposed to 500,000 atomic units for HDPE. Eagle 1610MB Blue High Density Polyethylene Lab Pack Drum with Metal Lever-Lock Lid, 14 Gallon Capacity, 26.5" Height, 15" Diameter (Pack of 4) 5.0 out of 5 stars 1 $147.58 $ 147 . A set of up to 130 kits for distribution to students contains samples of high-density polyethylene (HDPE) and low density polyethylene (LDPE) so that students can compare properties such as tensile strength. Polyethylene (PE), light, versatile synthetic resin made from the polymerization of ethylene. Above all, China, where beverage bottles made from HDPE were first imported in 2005, is a growing market for rigid HDPE packaging, as a result of its improving standard of living. Each property range of values reported is minimum and maximum values of appropriate MatWeb entries. High density polyethylene is also called PEHD (polyethylene high density), alkathene or polythene. Polyethylene (High Density) HDPE Polyethylene (Polythene) is one of the world’s most popular plastics. For example, in Rotational Molding, to identify the environmental stress crack resistance of a sample, the Notched Constant Tensile Load Test (NCTL) is put to use. What is High-Density Polyethylene? Principal uses are in packaging film, adhesives, toys, tubing, gaskets, wire coatings, drum liners, and carpet backing. High Density Polyethylene (HDPE) fabric is a cost effective material designed for basic modular structures and suited to large commercial projects where specifications require fabric exposed to environmental conditions including wind, rain, hail, dust and UV exposure. Material and … UHMWPE can be made through any catalyst technology, although Ziegler catalysts are most common. The High-density Polyethylene (HDPE) and Low-density Polyethylene (LDPE) have different mechanical properties such as the crystal structure, the magnitude and nature of branching and the molecular weight. Ethylene molecules are essentially composed of two methylene units (CH2) linked together by a double bond between the carbon atoms—a structure represented by the formula CH2=CH2. A thermoplastic is a polymer that becomes plastic/flexible upon heating, and of course, hardens upon cooling. In 2007, the global HDPE market reached a volume of more than 30 million tons.[2]. In 1930 Carl Shipp Marvel, an American chemist working at E.I. du Pont de Nemours & Company (now DuPont Company), discovered a high-density material, but the company failed to recognize the potential of the product. High-density polyethylene is made up of a string of ethylene molecules, which gives it the ‘poly’ in polyethylene. HDPE has a comparatively high density compared to other polymers, with a specific gravity of 0.95. Ethylene, commonly produced by the cracking of ethane gas, forms the basis for the largest single class of plastics, the polyethylenes. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. High density polyethylene is a thermoplastic polymer whose monomer unit is ethylene. The use of thermoplastic pipe systems, i.e., high density polyethylene (HDPE), are becoming increasingly popular for many applications, such as transporting gas, water, and chemicals. Unable to complete action, likely due to connectivity to Dow's back end service. HDPE is more crystalline than LDPE, and hence is more opaque, more rigid and has a higher tensile strength. The night she dissapered was good book I didn’t like that much though. Les structures internes pour l'absorption des chocs sont faites … The rigid and somewhat hard character is useful for a wide range of applications. This simple structure, repeated thousands of times in a single molecule, is the key to the properties of polyethylene. Autoclaving conditions are used to sterilise pro… High-density polyethylene (HDPE)(0.941