![Symbol Resin Code 2 HDPE](https://upload.wikimedia.org/wikipedia/commons/0/01/Symbol_Resin_Code_2_HDPE.svg)
High-density
polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including b ...
(HDPE) or polyethylene high-density (PEHD) is a
thermoplastic
A thermoplastic, or thermosoft plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.
Most thermoplastics have a high molecular weight. The polymer chains associate ...
polymer
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part")
is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...
produced from the monomer
ethylene. It is sometimes called "alkathene" or "polythene" when used for
HDPE pipe
HDPE pipe is a type of flexible plastic pipe used for fluid and gas transfer and is often used to replace ageing concrete or steel mains pipelines. Made from the thermoplastic HDPE (high-density polyethylene), its high level of impermeability and ...
s. With a high strength-to-density ratio, HDPE is used in the production of
plastic bottles
A plastic bottle is a bottle constructed from high-density or low density plastic. Plastic bottles are typically used to store liquids such as water, soft drinks, motor oil, cooking oil, medicine, shampoo, milk, and ink. The size ranges from v ...
, corrosion-resistant piping,
geomembrane
A geomembrane is very low permeability synthetic membrane liner or barrier used with any geotechnical engineering related material so as to control fluid (liquid or gas) migration in a human-made project, structure, or system. Geomembranes are ...
s and
plastic lumber
Plastic lumber is a plastic form of lumber made of virgin or recycled plastic (PL or RPL, respectively.) It is mostly made of plastic and binders such as fiberglass or rebar; not to be confused with wood-plastic composite lumber. Widely employe ...
. HDPE is commonly recycled, and has the number "2" as its
resin identification code
The ASTM International Resin Identification Coding System, often abbreviated RIC, is a set of symbols appearing on plastic products that identify the plastic resin out of which the product is made. It was developed in 1988 by the Society of t ...
.
In 2007, the global HDPE market reached a volume of more than 30 million tons.
Properties
HDPE is known for its high strength-to-density ratio. The density of HDPE ranges from 930 to 970 kg/m
3. The standard method to test plastic density is ISO 1183 part 2 (gradient columns), alternatively ISO 1183 part 1
MVS2PRO density analyzer. Although the density of HDPE is only marginally higher than that of
low-density polyethylene
Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its ...
, HDPE has little
branching, giving it stronger
intermolecular force
An intermolecular force (IMF) (or secondary force) is the force that mediates interaction between molecules, including the electromagnetic forces of attraction
or repulsion which act between atoms and other types of neighbouring particles, e.g. ...
s and
tensile strength
Ultimate tensile strength (UTS), often shortened to tensile strength (TS), ultimate strength, or F_\text within equations, is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials t ...
(38 MPa versus 21 MPa) than LDPE. The difference in strength exceeds the difference in density, giving HDPE a higher
specific strength
The specific strength is a material's (or muscle's) strength (force per unit area at failure) divided by its density. It is also known as the strength-to-weight ratio or strength/weight ratio or strength-to-mass ratio. In fiber or textile applic ...
. It is also harder and more opaque and can withstand somewhat higher
temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measurement, measured with a thermometer.
Thermometers are calibrated in various Conversion of units of temperature, temp ...
s (120 °C/248 °F for short periods). High-density polyethylene, unlike
polypropylene
Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene.
Polypropylene
belongs to the group of polyolefins a ...
, cannot withstand normally required
autoclaving
An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and/or temperature. Autoclaves are used before surgical procedures to perform steriliza ...
conditions. The lack of branching is ensured by an appropriate choice of
catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
(e.g.,
Ziegler–Natta catalyst A Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, is a catalyst used in the synthesis of polymers of 1-alkenes ( alpha-olefins). Two broad classes of Ziegler–Natta catalysts are employed, distinguished by their solubility:
* ...
s) and
reaction
Reaction may refer to a process or to a response to an action, event, or exposure:
Physics and chemistry
*Chemical reaction
*Nuclear reaction
* Reaction (physics), as defined by Newton's third law
*Chain reaction (disambiguation).
Biology and m ...
conditions.
High DPE is resistant to many different
solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
s, so it cannot be glued. Pipe joints must be made by welding.
The physical properties of HDPE can vary depending on the molding process that is used to manufacture a specific sample; to some degree, a determining factor is the international standardized testing methods employed to identify these properties for a specific process. 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.
Owing to these desirable properties, pipes constructed out of HDPE are ideally applicable for
drinking water
Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...
and waste water (storm and sewage).
Applications
File:HDPE Construction safety net.jpg, HDPE fibers can be spun into rope
File:Pulling on the hood of the Tyveck suit (5429334133).jpg, Disposable suits; nonwoven HDPE fabric
File:US Navy 100824-N-0858D-272 Sailors work on a new home for Habitat for Humanity during Boise Navy Week.jpg, Housewrap
Housewrap (or house wrap), also known by the genericized trademark homewrap (or home wrap), generally denotes a modern synthetic material used to protect buildings. Housewrap functions as a weather-resistant barrier, preventing rain or other fo ...
File:Registered Mail Royal Mail - Great Britain-Germany 2017 - envelope front side.jpg, Plastic mailing envelopes
File:Blue Striped Water Pipe.jpg, Flexible HDPE pipes
File:Hdpe pipe installation.jpg, Corrugated HDPE pipe installation in storm drain project in Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
File:Plastic outdoor chair 1 2017-06-14.jpg, The monobloc chair
File:Hanoi Vietnam The-omnipresent-plastic-chairs-01.jpg, Stools for outdoor use
File:Milk crate.jpg, Bottle crates
File:Cubocubo.png, Toys and playground equipment
File:2014. Уничтоженные гривны в Донецке 015.jpg, Clear plastic bags (shown) are made of LDPE; blown-film shopping bags with handles are now made of HDPE
File:250ml HDPE pump plastic bottle.jpg, HDPE is used to make sturdy bottles that resist oils. Transparent bottles are usually made of other plastics, such as polyethylene terephthalate
File:Bottle of milk.jpg, Milk jug
File:Diverse Kanisterformen.png, HDPE jerrycan
A jerrycan (also written as jerry can or jerrican) is a robust liquid container made from pressed steel (and more recently, high density polyethylene). It was designed in Germany in the 1930s for military use to hold of fuel, and saw wides ...
s resist softening and swelling from aromatic components of fuels
File:FODS Connect202 TC-1 TRACKOUT CONROL STABILIZED CONSTRUCTION ENTRANCE 2.jpg, Roller on HDPE construction entrance mat
HDPE has a wide variety of applications; for applications that fall within the properties of other polymers, the choice to use HDPE is usually economic:
*
3D printer
3D printing or additive manufacturing is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer co ...
filament
* Arena board (puck board)
* Backpacking frames
* Ballistic plates
* Banners
*
Bottle cap
A bottle cap or bottle top is a closure for the top opening of a bottle. A cap is sometimes colourfully decorated with the logo of the brand of contents. Plastic caps are used for plastic bottles, while metal with plastic backing is used for gl ...
s
* Boats
*
Chemical
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., w ...
containers
*
Chemical-resistant piping
*
Coax cable
Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a p ...
inner insulator
*
Conduit protector for electrical or communications cables
*
Corrosion
Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engi ...
protection for steel pipelines
* Electrical and plumbing boxes
* Far-IR
lenses
*
Fireworks
Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large number of devices ...
*
Folding chair
A folding chair is a type of folding furniture, a light, portable chair that folds flat or to a smaller size, and can be stored in a stack, in a row, or on a cart.
It can be combined with a folding table.
Uses
Folding chairs are generally used f ...
s and tables
*
Food storage container
Food storage containers are widespread in use throughout the world and have probably been in use since the first human civilizations.
Early civilizations
In early civilizations cereal grains such as maize, wheat, barley etc. were stored in large ...
s
*
Fuel tank
A fuel tank (also called a petrol tank or gas tank) is a safe container for flammable fluids. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelle ...
s for vehicles
*
Geomembrane
A geomembrane is very low permeability synthetic membrane liner or barrier used with any geotechnical engineering related material so as to control fluid (liquid or gas) migration in a human-made project, structure, or system. Geomembranes are ...
for hydraulic applications (such as canals and bank reinforcements)
*
Geothermal heat transfer piping systems
* Heat-resistant firework
mortars
Mortar may refer to:
* Mortar (weapon), an indirect-fire infantry weapon
* Mortar (masonry), a material used to fill the gaps between blocks and bind them together
* Mortar and pestle, a tool pair used to crush or grind
* Mortar, Bihar, a villag ...
*
Housewrap
Housewrap (or house wrap), also known by the genericized trademark homewrap (or home wrap), generally denotes a modern synthetic material used to protect buildings. Housewrap functions as a weather-resistant barrier, preventing rain or other fo ...
(
Tyvek
Tyvek () is a brand of synthetic flashspun high-density polyethylene fibers. The name "Tyvek" is a registered trademark of the American multinational chemical company DuPont, which discovered and commercialized Tyvek in the late 1950s and early ...
)
*
Hovercraft: The material is too heavy and dense for such craft but is still used occasionally
*
Ionizing radiation shield
*Laundry detergent jugs
*
Last
A last is a mechanical form shaped like a human foot. It is used by shoemakers and cordwainers in the manufacture and repair of shoes. Lasts typically come in pairs and have been made from various materials, including hardwoods, cast iron, an ...
s for shoes
* Microwave telescope windows
* Milk jugs
*
Natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
distribution pipe systems
*
Piping for fluid, slurry and gas purposes
*
Plastic bags
*
Plastic bottle
A plastic bottle is a bottle constructed from high-density or low density plastic. Plastic bottles are typically used to store liquids such as water, soft drinks, motor oil, cooking oil, medicine, shampoo, milk, and ink. The size ranges from v ...
s suitable both for recycling or re-use
*
Plastic surgery
Plastic surgery is a surgical specialty involving the restoration, reconstruction or alteration of the human body. It can be divided into two main categories: reconstructive surgery and cosmetic surgery. Reconstructive surgery includes cranio ...
(skeletal and facial reconstruction)
* Potable water mains
*
Root barrier
A root barrier is an underground wall placed to block plant roots. This is often for the purpose of protecting structures or other plants, but root barriers are also used to preserve soil moisture.
Development
Root barriers were developed to stop ...
* Shampoo bottles
* Sewage mains
*
Snowboard rails and boxes
*
Stone paper
*
Storage sheds
* Swimming pool installation
* Trackout control mats
* Telecom ducts
*
Water pipe
Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water delive ...
s for domestic water supply and agricultural processes
*
Wood plastic composite
Wood-plastic composites (WPCs)
are composite materials made of wood fiber/ wood flour and thermoplastic(s) such as polythene (PE), polypropylene (PP), polyvinyl chloride (PVC), or polylactic acid (PLA).
In addition to wood fiber and plastic, ...
s (utilizing
recycled polymers)
![T Joint cross section](https://upload.wikimedia.org/wikipedia/commons/8/8c/T_Joint_cross_section.jpg)
HDPE is also used for
cell liners in United States
subtitle D sanitary landfills, wherein large sheets of HDPE are either
extrusion welded or wedge welded to form a
homogeneous chemical-resistant barrier, with the intention of preventing the
pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...
of
soil
Soil, also commonly referred to as earth or dirt
Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty.
Common types of dirt include:
* Debri ...
and
groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated ...
by the liquid constituents of
solid waste.
HDPE is preferred by the
pyrotechnics trade for mortars over steel or
PVC tubes, being more durable and safer: HDPE tends to rip or tear in a malfunction instead of shattering and becoming shrapnel like the other materials.
Milk bottles, jugs, and other hollow goods manufactured through
blow molding
Blow molding (or moulding) is a manufacturing process for forming hollow plastic parts. It is also used for forming glass bottles or other hollow shapes.
In general, there are three main types of blow molding: extrusion blow molding, injectio ...
are the most important application area for HDPE, accounting for one-third of worldwide production, or more than 8 million tonnes.
Above all, China, where beverage bottles made from HDPE were first imported in 2005, is
growing marketfor rigid HDPE packaging, as a result of its improving
standard of living. In India and other highly populated, emerging nations, infrastructure expansion includes the deployment of pipes and cable insulation made from HDPE.
The material has benefited from discussions about possible health and environmental problems caused by PVC and
polycarbonate associated
bisphenol A (BPA), as well as its advantages over glass, metal, and cardboard.
See also
*
Cross-linked polyethylene
Cross-linked polyethylene, commonly abbreviated PEX, XPE or XLPE, is a form of polyethylene with cross-links. It is used predominantly in building services pipework systems, hydronic radiant heating and cooling systems, domestic water piping, ins ...
(PEX)
*
HDPE pipe
HDPE pipe is a type of flexible plastic pipe used for fluid and gas transfer and is often used to replace ageing concrete or steel mains pipelines. Made from the thermoplastic HDPE (high-density polyethylene), its high level of impermeability and ...
(HDPE)
*
Low-density polyethylene
Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its ...
(LDPE)
*
Linear low-density polyethylene
Linear low-density polyethylene (LLDPE) is a substantially linear polymer (polyethylene), with significant numbers of short branches, commonly made by copolymerization of ethylene with longer-chain olefins. Linear low-density polyethylene differs ...
(LLDPE)
*
Medium-density polyethylene
Medium-density polyethylene (MDPE) is a type of polyethylene defined by a density range of 0.926–0.940 g/cm3. It is less dense than HDPE, which is more common.
MDPE can be produced by chromium/silica catalysts, Ziegler-Natta catalysts or met ...
(MDPE)
*
Phillips Disaster
*
Plastic recycling
Plastic recycling is the reprocessing of plastic waste into new products. When performed correctly, this can reduce dependence on landfill, conserve resources and protect the environment from plastic pollution and greenhouse gas emissions.
A ...
*
Polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including b ...
(PE)
*
Resin identification code
The ASTM International Resin Identification Coding System, often abbreviated RIC, is a set of symbols appearing on plastic products that identify the plastic resin out of which the product is made. It was developed in 1988 by the Society of t ...
*
Stretch wrap
Stretch wrap or stretch film is a highly stretchable plastic film that is wrapped around items. The elastic recovery keeps the items tightly bound. In contrast, shrink wrap is applied loosely around an item and shrinks tightly with heat. While ...
*
Ultra-high-molecular-weight polyethylene
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. ...
(UHMWPE)
References
{{DEFAULTSORT:High-Density Polyethylene
Plastics
Polyolefins
de:Polyethylen