Polyurethane
Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane is produced from ...
products have many uses. Over three quarters of the global consumption of polyurethane products is in the form of foams, with flexible and rigid types being roughly equal in market size. In both cases, the foam is usually behind other materials: flexible foams are behind upholstery fabrics in commercial and domestic furniture; rigid foams are between metal, or plastic walls/sheets of most
refrigerators and freezers, or other surface materials in the case of thermal
insulation panels in the construction sector. Its use in garments is growing: for example, in lining the cups of brassieres. Polyurethane is also used for moldings which include door frames, columns, balusters, window headers, pediments, medallions and rosettes.
Polyurethane formulations cover an extremely wide range of stiffness, hardness, and densities.
[ These materials include:
* Low-density flexible ]foam
Foams are materials formed by trapping pockets of gas in a liquid or solid.
A bath sponge and the head on a glass of beer are examples of foams. In most foams, the volume of gas is large, with thin films of liquid or solid separating the ...
used in upholstery
Upholstery is the work of providing furniture, especially seats, with padding, springs, webbing, and fabric or leather covers. The word also refers to the materials used to upholster something.
''Upholstery'' comes from the Middle English w ...
, bedding, automotive and truck seating, and novel inorganic plant substrates for roof or wall gardens
* Low density elastomers
An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials. The term, a portmanteau of ''elastic p ...
used in footwear
* Hard solid plastics used as electronic instrument bezels and structural parts
* Flexible plastics used as straps and bands
* Cast and injection molded components for various markets – i.e., agriculture, military, automotive, industrial, etc.
Polyurethane foam is widely used in high resiliency flexible foam seating, rigid foam insulation panels, microcellular foam seal
Seal may refer to any of the following:
Common uses
* Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly:
** Earless seal, or "true seal"
** Fur seal
* Seal (emblem), a device to imp ...
s and gasket
Some seals and gaskets
A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. It is a deformable material that is used to c ...
s, durable elastomeric wheels and tires, automotive suspension bushings, electrical potting compounds, seals, gaskets, carpet
A carpet is a textile floor covering typically consisting of an upper layer of pile attached to a backing. The pile was traditionally made from wool, but since the 20th century synthetic fibers such as polypropylene, nylon, or polyester hav ...
underlay, and hard plastic parts (such as for electronic instruments).
Usage per application
The following table shows an example how polyurethanes were used in one country over a dozen years ago (US data from 2004):
Cleaning products
Polyurethane foam is used to make many kitchen and bathroom sponges.
Furniture
Open cell flexible polyurethane foam (FPF) is made by mixing polyols
In organic chemistry, a polyol is an organic compound containing multiple hydroxyl groups (). The term "polyol" can have slightly different meanings depending on whether it is used in food science or polymer chemistry. Polyols containing two, thr ...
, diisocyanate
In organic chemistry, isocyanate is the functional group with the formula . Organic compounds that contain an isocyanate group are referred to as isocyanates. An organic compound with two isocyanate groups is known as a diisocyanate. Diisocyan ...
s, catalysts, auxiliary blowing agents and other additives and allowing the resulting foam to rise freely. Most FPF is manufactured using continuous processing technology and also can be produced in batches where relatively small blocks of foam are made in open-topped molds, boxes, or other suitable enclosurers. The foam is then cut to the desired shape and size for use in a variety of furniture and furnishings applications.
Applications for flexible polyurethane foam include upholstered
Upholstery is the work of providing furniture, especially seats, with padding, springs, webbing, and fabric or leather covers. The word also refers to the materials used to upholster something.
''Upholstery'' comes from the Middle English word ...
furniture cushions, automotive seat cushions and interior trim, carpet cushion
A carpet is a textile floor covering typically consisting of an upper layer of pile attached to a backing. The pile was traditionally made from wool, but since the 20th century synthetic fibers such as polypropylene, nylon, or polyester hav ...
, and mattress padding and solid-core mattress cores.
Flexible polyurethane foam is a recyclable product.
Automobile seats
Flexible and semi-flexible polyurethane foams are used extensively for interior components of automobile
A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods.
The year 1886 is regarde ...
s, in seats, headrests, armrests, roof liners, dashboard For business applications, see Dashboard (business).
A dashboard (also called dash, instrument panel (IP), or fascia) is a control panel set within the central console of a vehicle or small aircraft. Usually located directly ahead of the drive ...
s and instrument panels.
Polyurethanes are used to make automobile seats in a remarkable manner. The seat manufacturer has a mold
A mold () or mould () is one of the structures certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not ...
for each seat model. The mold is a closeable "clamshell" sort of structure that will allow quick casting of the seat cushion, so-called molded flexible foam, which is then upholstered after removal from the mold.
It is possible to combine these two steps, so-called ''in-situ'', foam-in-fabric or direct moulding. A complete, fully assembled seat cover is placed in the mold and held in place by vacuum drawn through small holes in the mold. Sometimes a thin pliable plastic film backing on the fabric is used to help the vacuum work more effectively. The metal seat frame is placed into the mold and the mold closed. At this point the mold contains what could be visualized as a "hollow seat", a seat fabric held in the correct position by the vacuum and containing a space with the metal frame in place.
Polyurethane chemicals are injected by a mixing head into the mold cavity. Then the mold is held at a preset reaction temperature until the chemical mixture has foamed, filled the mold, and formed a stable soft foam. The time required is two to three minutes, depending on the size of the seat and the precise formulation and operating conditions. Then the mold is usually opened slightly for a minute or two for an additional cure time, before the fully upholstered seat is removed.
Houses, sculptures, and decorations
The walls and ceiling (not just the insulation) of the futuristic Xanadu House
The Xanadu Houses were a series of experimental homes built to showcase examples of computers and automation in the home in the United States. The architectural project began in 1979, and during the early 1980s three houses were built in diffe ...
in Florida, USA, were built out of polyurethane foam. Domed ceilings and other odd shapes are easier to make with foam than with wood. Foam was used to build oddly shaped buildings, statues, and decorations in the Seuss Landing section of the Islands of Adventure
Universal's Islands of Adventure (also known as Islands of Adventure or IOA), originally called Universal Studios Islands of Adventure, is a theme park located in Orlando, Florida. It opened on May 28, 1999, along with CityWalk, as part of an ...
(USA) theme park. Rigid foam manufacturers sell foam that replace wood in carved sign and 3D-topography industries. PU foam is also used as a thermal insulator
Thermal insulation is the reduction of heat transfer (i.e., the transfer of thermal energy between objects of differing temperature) between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with s ...
in many houses.
Polyurethane resin is used as an aesthetic flooring material. Being seamless and water resistant, it is gaining interest for use in (modern) interiors, especially in Western Europe.
Image:Polyurethane insulator.jpg, Polyurethane being used as an insulator in house construction (yellow layer).
File:Polyurethane the new Wattle and Daub, Brookend, Welland. - geograph.org.uk - 5811.jpg, Polyurethane foam as a wall insulation
File:Xanadu - lily pads.jpg, Xanadu House
The Xanadu Houses were a series of experimental homes built to showcase examples of computers and automation in the home in the United States. The architectural project began in 1979, and during the early 1980s three houses were built in diffe ...
with polyurethane foam walls and ceiling
Image:Puf shrinkage over time 002.png, Polyurethane foam used as joist cavity insulation at a restaurant near Philadelphia
Philadelphia, often called Philly, is the List of municipalities in Pennsylvania#Municipalities, largest city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, the List of United States cities by population, sixth-largest city i ...
, not in direct sunlight, exhibiting shrinkage at the bond interface.
File:Flame Retardant Research - LDH materials (16241017250).jpg, Flame test. Top, untreated polyurethane foam burns vigorously. Bottom, with fire-retardant.
Filling of spaces and cavities
Two binary liquid
Binary liquid is a type of chemical combination, which creates a special reaction or feature as a result of mixing two liquid chemicals, that are normally inert or have no function by themselves. A number of chemical products are produced as a res ...
s, one of which is a polyurethane (either T6 or 16), when mixed and aerated, expand into a hard, space-filling aerosolid.
Construction sealants and firestopping
Approved polyurethane sealants (which is different from foam) are available in one, two and three part systems, and in cartridges, buckets or drums. Polyurethane sealants (such as EZ-Poly) are used to fill gaps thereby preventing air and water leakage. They are also used in conjunction with inorganic insulation, such as rockwool
Mineral wool is any fibrous material formed by spinning or drawing molten mineral or rock materials such as slag and ceramics.
Applications of mineral wool include thermal insulation (as both structural insulation and pipe insulation), f ...
or ceramic fibres, for firestop
A firestop or fire-stopping is a form of passive fire protection that is used to seal around openings and between joints in a fire-resistance-rated wall or floor assembly. Firestops are designed to maintain the fire-resistance rating of a wall ...
ping. Firestops can thwart smoke
Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-produc ...
and hose-stream passage. The Browns Ferry Nuclear Power Plant
The Browns Ferry Nuclear Plant is located on the Tennessee River near Decatur and Athens, Alabama, on the north side (right bank) of Wheeler Lake. The site has three General Electric boiling water reactor (BWR) nuclear generating units and i ...
used flammable polyurethane foam as a firestop, which was accidentally ignited and caused a major fire.
Water vessels
Inflatable boats
Some raft manufacturers use urethane for the construction of inflatable boats. AIRE uses urethane membrane material as an air-retentive bladder inside a PVC shell, whereas SOTAR uses urethane membrane materials as a coating on some boats. Maravia uses a liquid urethane material which is spray-coated over PVC to enhance air retention and increase abrasion resistance.
Surfboards
Some surfboards are made with a rigid polyurethane core. A rigid foam blank is molded, shaped to specification, then covered with fiberglass cloth and polyester resin.
Rigid-hulled boats
Some boat hulls have a rigid polyurethane foam core sandwiched between fiberglass skins. The foam provides strength, buoyancy
Buoyancy (), or upthrust, is an upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the ...
, and sound deadening.
Boat decks and outdoor marine surface areas
Some boat decks including U.S Navy and Pakistani fishing vessels use specialized polyurethane sealants to protect from constant moisture and harsh oceanic elements. As an example, Durabak-M26 uses a custom single-part polyurethane to prevent water seepage to unwanted areas.
Water tanks
Some water tanks are insulated with polyurethane chemicals (polyol and isocyanates) to maintain water temperature for long periods of time.
Flexible plastics
Tennis grips
Polyurethane has been used to make several Tennis Overgrips such as Yonex Super Grap, Wilson Pro Overgrip and many other grips. These grips are highly stretchable to ensure the grip wraps neatly around the racquet's handle.
Watch-band wrapping
Polyurethane is used as a black wrapping for timepiece bracelets over the main material which is generally stainless steel. It is used for comfort, style, and durability.
Textiles
A thin film of polyurethane finish is added to a polyester weave to create polyurethane laminate
Polyurethane laminate (PUL, thermal stretch, fuzzy rubber) is a compound fabric made by laminating a cloth fabric to one or both sides of a thin film of polyurethane. Polyurethane laminated fabrics have a wide range of applications in medical, au ...
(PUL), which is used for its waterproof and windproof properties in outerwear, diapers, shower curtains, and so forth. PU is used in some cutting-edge swimsuits to provide buoyancy for competitive swimmers. There are restrictions as the buoyancy enhances swimming performance.
A still more popular use of polyurethane in textiles is in the form of spandex
Spandex, Lycra, or elastane is a synthetic fiber known for its exceptional elasticity. It is a polyether-polyurea copolymer that was invented in 1958 by chemist Joseph Shivers at DuPont's Benger Laboratory in Waynesboro, Virginia, US.
The g ...
, also known as elastane or by DuPont's brand name Lycra. Polyurethane fiber
Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorpora ...
s in the form of spandex can stretch up to 600% and still return to their original shape. Spandex is spun with other fibers, such as cotton, nylon, or polyester, to create stretchable fibers essential for clothing for both sports and fashion.
Varnish
Polyurethane materials are commonly formulated as paints and varnishes for finishing coats to protect or seal wood. This use results in a hard, abrasion-resistant, and durable coating that is popular for hardwood floors, but considered by some to be difficult or unsuitable for finishing furniture or other detailed pieces. Relative to oil or shellac varnishes, polyurethane varnish forms a harder film which tends to de-laminate if subjected to heat or shock, fracturing the film and leaving white patches. This tendency increases when it is applied over softer woods like pine
A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts ...
. This is also in part due to polyurethane's lesser penetration into the wood. Various priming techniques are employed to overcome this problem, including the use of certain oil varnishes, specified "dewaxed" shellac
Shellac () is a resin secreted by the female lac bug on trees in the forests of India and Thailand. It is processed and sold as dry flakes and dissolved in alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and ...
, clear penetrating epoxy, or "oil-modified" polyurethane designed for the purpose. Polyurethane varnish may also lack the "hand-rubbed" lustre of drying oil
A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components crosslink (and hence, polymerize) by the action of oxygen (no ...
s such as linseed
Flax, also known as common flax or linseed, is a flowering plant, ''Linum usitatissimum'', in the family Linaceae. It is cultivated as a food and fiber crop in regions of the world with temperate climates. Textiles made from flax are known in W ...
or tung oil
Tung oil or China wood oil is a drying oil obtained by pressing the seed from the nut of the tung tree (''Vernicia fordii''). The oil and its use are believed to have originated in ancient China and appear in the writings of Confucius from ab ...
; in contrast, however, it is capable of a much faster and higher "build" of film, accomplishing in two coats what may require many applications of oil. Polyurethane may also be applied over a straight oil finish, but because of the relatively slow curing time of oils, the presence of volatile byproducts of curing, and the need for extended exposure of the oil to oxygen, care must be taken that the oils are sufficiently cured to accept the polyurethane.
Unlike drying oil
A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components crosslink (and hence, polymerize) by the action of oxygen (no ...
s and alkyd
An alkyd is a polyester resin modified by the addition of fatty acids and other components. Alkyds are derived from polyols and organic acids including dicarboxylic acids or carboxylic acid anhydride and triglyceride oils. The term ''alkyd'' is a m ...
s which cure, after evaporation of the solvent, upon reaction with oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
from the air, polyurethane coatings cure after evaporation of the 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 ...
by a variety of reactions of 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 ...
s within the original mix, or by reaction with moisture
Moisture is the presence of a liquid, especially water, often in trace amounts. Small amounts of water may be found, for example, in the air (humidity), in foods, and in some commercial products. Moisture also refers to the amount of water vapo ...
from the air. Certain products are "hybrids" and combine different aspects of their parent components. "Oil-modified" polyurethanes, whether water-borne or solvent-borne, are currently the most widely used wood floor finishes.
Exterior use of polyurethane varnish may be problematic due to its susceptibility to deterioration through ultra-violet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiatio ...
(UV) light exposure. All clear or translucent varnishes, and indeed all film-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 ...
coatings (i.e., paint, stain, epoxy, synthetic plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
, etc.) are susceptible to this damage in varying degrees. Pigment
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...
s in paints and stains protect against UV damage, while UV-absorbers are added to polyurethane and other varnishes (in particular "spar
SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...
" varnish) to work against UV damage. Polyurethanes are typically the most resistant to water exposure, high humidity, temperature extremes, and fungus or mildew, which also adversely affect varnish and paint performance.
Wheels
Polyurethane is also used in making solid tires
A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which t ...
and wheels. Industrial applications include forklift drive and load wheels, grocery and industrial carts, and roller coaster wheels. Modern roller blading and skateboard
A skateboard is a type of sports equipment used for skateboarding. They are usually made of a specially designed 7-8 ply maple plywood deck and polyurethane wheels attached to the underside by a pair of skateboarding trucks.
The skateboarder ...
ing became economical only with the introduction of tough, abrasion-resistant polyurethane parts, helping to usher in the popularity of what had once been an obscure 1960s craze. The durability of polyurethane wheels allowed the range of tricks and stunts performed on skateboards
A skateboard is a type of sports equipment used for skateboarding. They are usually made of a specially designed 7-8 ply maple plywood deck and polyurethane wheels attached to the underside by a pair of skateboarding trucks.
The skateboarder ...
to expand considerably. Polyurethane is also used to make small equipment tires in the lawn and garden industry for wheelbarrows, hand trucks, lawn mowers, carts, etc. They provide the bounce and feel of an air-filled tire with the benefit of no punctures. They weigh about the same as air-filled tires as well, even though they are solid polyurethane all the way through. Other constructions have been developed for pneumatic tires, and microcellular foam variants are widely used in tires on wheelchairs, bicycles and other uses. These latter foam types are also widely encountered in car steering wheels and other interior and exterior automotive parts, including bumpers and fenders.
Automotive parts
Polyurethane usage has increased over the past twenty years in the automotive industry. It is being used to replace traditional rubber bushings which are known to fail or wear out on road surfaces prone to large amounts of salt and chemical debris.
Using polyurethane bushings can have many benefits like maintaining the right alignment of caster, camber and toe and thereby increasing the overall control and handling. It also increases the lifespan, provides more resistance to wear out and is less pervious to oil and similar road contaminants.
Polyurethane (PU) is popularized in the manufacturing of some of the highest quality aerodynamic components /body kits ( body kits) for varying automobiles (car, truck, and SUV) on the market. These components include bumpers, side skirts, roll pans, and wiper cowls. Polyurethane allows production of durable components unlike the conventional fiberglass (FRP) that can easily break upon impact. Polyurethane is highly flexible therefore more resistant to damage. Including durability, these body kits when produced by a reputable manufacturer, exhibits less imperfections, are easy to install and maintain, and are affordable.[
]
When fiberglass body kits begin to show cracks, chips from usual wear and tear, a well manufactured polyurethane components have similar durability to a factory installed bumper. As mentioned above, when produced by a reputable manufacturer, tend to have less pinholes and casting imperfections. Flexibility of polyurethane makes them easy to work with. Installation can be completed individually as a "do-it-yourself" project. Maintenance is extremely simple. Concerning pricing, it may vary depending on the manufacturer but are kept between an affordable range. As good as it sounds, polyurethane body kits too have its downfalls. Fiberglass or carbon fiber components are lighter in weight than most polyurethane kits. Polyurethane, again is flexible but more material and thickness is most often needed to keep adequate stiffness for road use. For drivers seeking speed for their higher performance vehicle, this can become a problem. Also, unlike fiberglass, polyurethane cannot be patched or repaired. Though it is much harder to damage, if damage did occur, the entire component must be removed and replaced. There are varying options when purchasing polyurethane kits.
Electronic components
Often electronic components are protected from environmental influence and mechanical shock by enclosing
Enclosure or Inclosure is a term, used in English landownership, that refers to the appropriation of "waste" or "common land" enclosing it and by doing so depriving commoners of their rights of access and privilege. Agreements to enclose land ...
them in polyurethane. Typically polyurethanes are selected for the excellent abrasion resistances, good electrical properties, excellent adhesion, impact strength, and low-temperature flexibility. The disadvantage of polyurethanes is the limited upper service temperature (typically 250 °F (121 °C)). In production the electronic manufacture would purchase a two-part urethane (resin and catalyst) that would be mixed and poured onto the circuit assembly (see Resin dispensing). In most cases, the final circuit board assembly would be unrepairable after the urethane has cured. Because of its physical properties and low cost, polyurethane encapsulation (potting) is a popular option in the automotive manufacturing sector for automotive circuits and sensors.
Adhesives
Polyurethane can be used as an adhesive, especially as a woodworking glue. Its main advantage over more traditional wood glues is its water resistance. It was introduced to the general North American market in the 1990s as '' Gorilla Glue'' and ''Excel'', but had been available in Europe much earlier. Polyurethane is the basis for some construction adhesives in a caulking
Caulk or, less frequently, caulking is a material used to seal joints or seams against leakage in various structures and piping.
The oldest form of caulk consisted of fibrous materials driven into the wedge-shaped seams between boards on ...
tube format.
On the way to a new and better glue for bookbinder
Bookbinding is the process of physically assembling a book of codex format from an ordered stack of ''signatures'', sheets of paper folded together into sections that are bound, along one edge, with a thick needle and strong thread. Cheaper, ...
s, a new adhesive system was introduced for the first time in 1985. The base for this system is polyether or polyester, whereas polyurethane (PUR) is used as prepolymer. Its special features are coagulation at room temperature and resistance to moisture.
First generation (1988)
* Low starting solidity
* High viscosity
* Cure time >3 days
Second generation (1996)
* Low starting solidity
* High viscosity
* Cure time <3 days
Third generation (2000)
* Good starting solidity
* Low viscosity
* Cure time between 6 and 16 hours
Fourth generation (present)
* Good starting solidity
* Very low viscosity
* Cure reached within a few seconds due to dual-core systems
Advantages of polyurethane glue in the bookbinding industry:
* PUR is better than hotmelt or cold glue for most applications. Because of the lack of moisture in the glue, paper with contrary grain direction can be glued without problems. Even printed and supercalendered paper can be bound without problems. It is the most economical glue, with a theoretical application thickness of 0.01 mm. However, in actual use, it is not practical to apply less than 0.03 mm.
* PUR glue is weather-proof, and stable at temperatures from to .
Abrasion resistance
Thermoset polyurethanes are also used as a protective coating against abrasion. Cast polyurethane over materials such as steel will absorb particle impact more efficiently. Polyurethanes have been proven to last in excess of 25 years in abrasive environments where non-coated steel would erode in less than 8 years. Polyurethanes are used in industries such as:
* Mining and mineral processing
* Aggregate
* Transportation
* Concrete
* Paper processing
* Power
* Inflatable boat manufacture
Polyurethane is also used in the concrete construction industry to create formliners. Polyurethane formliners serves as a mold for concrete, creating a variety of textures and art.
Solid-fuel rockets
Polyurethane is used together with Ammonium perchlorate as solid fuel in the submarine launched Polaris missile
The UGM-27 Polaris missile was a two-stage solid-fueled nuclear-armed submarine-launched ballistic missile (SLBM). As the United States Navy's first SLBM, it served from 1961 to 1980.
In the mid-1950s the Navy was involved in the Jupiter missi ...
s.
Body armor
Polyurethane urea elastomers have been investigated by researchers from the U.S. Army Research Laboratory and the Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
for potential material for helmets, face shields, and ballistic vests for soldiers.
Inorganic plant substrates
Sheet and flaked semi-open cell hydrophilic polyurethane foams have found application in roof gardens and vertical green walls with commercial products now emerging on the market. Semi-open cell polyurethane foams substrates have much lower density and far greater water holding capacities than soil substrates. The semi-open cell structure facilitate the required plant root attachment for vertical wall gardens. Reductions in weight reduce building/wall supporting structure requirements, whilst increased water holding capacity reduces plant watering requirements.
Concrete raising
Closed cell polymers have been used to raise and support concrete roadways and bridge approaches since 1989. Originally developed in Europe an
patented
by Uretek, this method of concrete leveling is now widely used in residential, commercial and municipal applications. Common applications include repairing settled sidewalks, driveways, patios and garage floors.
References
{{DEFAULTSORT:List Of Polyurethane Applications
Polyurethanes
Science-related lists