Acrylic glass
Encyclopedia
Thermoplastic
Thermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
, often used as a light or shatter-resistant alternative to glass
Glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
. It is sometimes called acrylic glass. Chemically, it is the synthetic polymer of methyl methacrylate
Methyl methacrylate
Methyl methacrylate is an organic compound with the formula CH2=CCOOCH3. This colourless liquid, the methyl ester of methacrylic acid is a monomer produced on a large scale for the production of poly .-Production:...
. The material was developed in 1928 in various laboratories, and was first brought to market in 1933 by Rohm and Haas Company
Rohm and Haas
Rohm and Haas Company, a Philadelphia, Pennsylvania based company, manufactures miscellaneous materials. Formerly a Fortune 500 Company, Rohm and Haas employs more than 17,000 people in 27 countries, with its last sales revenue reported as an independent company at USD 8.9 billion. On July 10,...
, under the trademark Plexiglas. It has since been sold under many different names including Lucite and Perspex.
The often-seen spelling poly(methyl 2-methylpropanoate) with -an- is an error for poly(methyl 2-methylpropenoate), based on propenoic acid.
PMMA is an economical alternative to polycarbonate
Polycarbonate
PolycarbonatePhysical PropertiesDensity 1.20–1.22 g/cm3Abbe number 34.0Refractive index 1.584–1.586FlammabilityV0-V2Limiting oxygen index25–27%Water absorption – Equilibrium0.16–0.35%Water absorption – over 24 hours0.1%...
(PC) when extreme strength is not necessary. Additionally, PMMA does not contain the potentially harmful bisphenol-A subunits found in polycarbonate. It is often preferred because of its moderate properties, easy handling and processing, and low cost, but behaves in a brittle manner when loaded, especially under an impact force, and is more prone to scratching compared to conventional inorganic glass.
History
The first acrylic acid was created in 1843. Methacrylic acidMethacrylic acid
Methacrylic acid, abbreviated MAA, is an organic compound. This colourless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its...
, derived from acrylic acid
Acrylic acid
Acrylic acid is an organic compound with the formula CH2=CHCO2H. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols,...
, was formulated in 1865. The reaction between methacrylic acid and methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
results in the ester methyl methacrylate
Methyl methacrylate
Methyl methacrylate is an organic compound with the formula CH2=CCOOCH3. This colourless liquid, the methyl ester of methacrylic acid is a monomer produced on a large scale for the production of poly .-Production:...
. The German chemists Fittig
Wilhelm Rudolph Fittig
Wilhelm Rudolph Fittig was a German chemist. Fittig discovered the pinacol coupling reaction, mesitylene, diacetyl and biphenyl. He studied the action of sodium on ketones and hydrocarbons...
and Paul discovered in 1877 the polymerization process that turns methyl methacrylate into polymethyl methacrylate. In 1933 the German chemist Otto Röhm
Otto Röhm
Otto Karl Julius Röhm was one of the founders and a longtime president of the Röhm und Haas chemical company which became later in the USA the Rohm & Haas PLC and in Germany the Röhm GmbH .- Life :After completion of an apprenticeship as pharmacy assistant he started to study pharmacy at...
patented and registered the brand name PLEXIGLAS. In 1936 the first commercially viable production of acrylic safety glass began. During World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
acrylic glass was used for submarine periscopes, windshields, canopies, and gun turrets for airplanes.
Names
PMMA has been sold under a variety of brand names and generic names. It is often generically called acrylic glass, although it is chemically unrelated to glassGlass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
. It is sometimes called simply acrylic, although acrylic can also refer to other polymers or copolymers containing polyacrylonitrile
Polyacrylonitrile
Polyacrylonitrile is a synthetic, semicrystalline organic polymer resin, with the linear formula n. Though it is thermoplastic, it does not melt under normal conditions. It degrades before melting. It melts above 300 degrees Celsius only if the heating rates are 50 degrees per minute or above...
. Other notable trade names include:
- Lucite
- Plexiglas
- Optix (Plaskolite)
- Perspex
- Altuglas (ArkemaArkemaArkema is a French producer of chemicals headquartered in Colombes, near Paris, France.Created in 2004 when French oil major Total restructured its Chemicals business, Arkema has 14,000 employees in more than 40 countries, seven research centers worldwide, and a total of 80 production plants in...
)
Synthesis
PMMA is routinely produced by emulsion polymerizationEmulsion polymerization
Emulsion polymerization is a type of radical polymerization that usually starts with an emulsion incorporating water, monomer, and surfactant. The most common type of emulsion polymerization is an oil-in-water emulsion, in which droplets of monomer are emulsified in a continuous phase of water...
, solution polymerization
Solution polymerization
Solution polymerization is a method of industrial polymerization. In this procedure, a monomer is dissolved in a non-reactive solvent that contains a catalyst....
and bulk polymerization
Bulk polymerization
Bulk polymerization or mass polymerization is carried out by adding a soluble initiator to pure monomer into liquid state.Bulk polymerization has several advantages over other methods, these advantages are :...
. Generally radical initiation is used (including living polymerization
Living polymerization
In polymer chemistry, living polymerization is a form of addition polymerization where the ability of a growing polymer chain to terminate has been removed. This can be accomplished in a variety of ways. Chain termination and chain transfer reactions are absent and the rate of chain initiation is...
methods), but anionic polymerization of PMMA can also be performed. To produce 1 kg (2.2 lb) of PMMA, about 2 kg (4.4 lb) of petroleum
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
is needed. PMMA produced by radical polymerization
Radical polymerization
Free radical polymerization is a method of polymerization by which a polymer forms by the successive addition of free radical building blocks. Free radicals can be formed via a number of different mechanisms usually involving separate initiator molecules...
(all commercial PMMA) is atactic and completely amorphous.
Processing
The glass transition temperature (Tg) of atactic PMMA is 105 °C. The Tg values of commercial grades of PMMA range from 85 to 165 °C (185 to 329 F); the range is so wide because of the vast number of commercial compositions which are copolymers with co-monomers other than methyl methacrylate. PMMA is thus an organic glass at room temperature — i.e., it is below its Tg. The forming temperature starts at the glass transition temperature and goes up from there. All common molding processes may be used, including injection moldingInjection molding
Injection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the cavity...
, compression molding
Compression molding
Compression molding is a method of molding in which the molding material, generally preheated, is first placed in an open, heated mold cavity. The mold is closed with a top force or plug member, pressure is applied to force the material into contact with all mold areas, while heat and pressure are...
and extrusion
Extrusion
Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section...
. The highest quality PMMA sheets are produced by cell casting
Cell casting
Cell casting is a method used for creating poly sheets. Liquid monomer is poured between two flat sheets of toughened glass sealed with a rubber gasket and heated for polymerization...
, but in this case, the polymerization and molding steps occur concurrently. The strength of the material is higher than molding grades owing to its extremely high molecular mass
Molecular mass
The molecular mass of a substance is the mass of one molecule of that substance, in unified atomic mass unit u...
. Rubber toughening
Rubber toughening
Many thermoplastics such as polystyrene and PMMA are brittle when stressed, a property which limits applications. A good way of strengthening such polymers is to copolymerise elastomeric chains during manufacture...
has been used to increase the strength of PMMA owing to its brittle behavior in response to applied loads.
Handling, cutting, and joining
PMMA can be joined using cyanoacrylateCyanoacrylate
Cyanoacrylate is the generic name for cyanoacrylate based fast-acting adhesives such as methyl 2-cyanoacrylate, ethyl-2-cyanoacrylate , and n-butyl cyanoacrylate...
cement, more commonly known as superglue, with heat (welding), or by using solvents such as di-
Dichloromethane
Dichloromethane is an organic compound with the formula CH2Cl2. This colorless, volatile liquid with a moderately sweet aroma is widely used as a solvent. Although it is not miscible with water, it is miscible with many organic solvents...
or trichloromethane
Chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
to dissolve the plastic at the joint which then fuses and sets, forming an almost invisible weld. Scratches may easily be removed by polishing or by heating the surface of the material.
Laser cutting
Laser cutting
Laser cutting is a technology that uses a laser to cut materials, and is typically used for industrial manufacturing applications, but is also starting to be used by schools, small businesses and hobbyists. Laser cutting works by directing the output of a high-power laser, by computer, at the...
may be used to form intricate designs from PMMA sheets. PMMA vaporizes to gaseous compounds (including its monomers) upon laser cutting, so a very clean cut is made, and cutting is performed very easily. However, the pulsed lasercutting introduces a high internal stresses along the cut edge, which when exposed to solvents produces undesirable "stress-crazing" at the cut edge and several millimetres deep. Even ammonium-based glass-cleaner and almost everything short of soap-and-water produces similar undesirable crazing, sometimes over the entire surface of the cut parts, at great distances from the stressed edge. Annealing the PMMA sheet/parts is therefore an obligatory post-processing step when intending to chemically bond lasercut parts together. This involves heating the parts in an air circulating oven from room temperature up to 90°C (at a rate of no more than 18 degrees per hour) down to room temperature (at a rate of no more than 12 degrees per hour). Temperature should be maintained as follows: one hour for 3mm thickness, two hours for up to 6mm thickness, four hours for up to 12mm thickness, and six hours for up to 20mm thickness. A rapid annealing cycle is reliable for thin sheets and involves placing them in a pre-heated oven to 80°C for one hour, then removing parts from oven and allowing to cool to room temperature. This added time component should be factored into the whole fabrication process, and the alternative Zero-rake sawcutting technique may provide better cost-effectiveness, unless complex non-straight line edges are required. In this respect PMMA has an advantage over competing polymers such as polystyrene
Polystyrene
Polystyrene ) also known as Thermocole, abbreviated following ISO Standard PS, is an aromatic polymer made from the monomer styrene, a liquid hydrocarbon that is manufactured from petroleum by the chemical industry...
and polycarbonate, which require higher laser powers and give more messy and charred laser cuts.
In the majority of applications, it will not shatter. Rather, it breaks into large dull pieces. Since PMMA is softer and more easily scratched than glass, scratch-resistant coatings
Anti-scratch coating
An anti-scratch or scratch-resistant coating is a film or coating that can be applied to optical surfaces, such as the faces of a lens or photographic film. The coating does not interfere with how the lenses function and does not affect vision, but creates a permanent bond with the lens that...
are often added to PMMA sheets to protect it (as well as possible other functions).
Acrylate resin casting
Methyl methacrylate
Methyl methacrylate is an organic compound with the formula CH2=CCOOCH3. This colourless liquid, the methyl ester of methacrylic acid is a monomer produced on a large scale for the production of poly .-Production:...
"synthetic resin
Synthetic resin
Synthetic resins are materials with a property of interest that is similar to natural plant resins: they are viscous liquids that are capable of hardening permanently. Otherwise, chemically they are very different from the various resinous compounds secreted by plants .The synthetics are of several...
" for casting (simply the bulk liquid chemical) may be used in conjunction with a polymerization catalyst such as MEKP, to produce hardened transparent PMMA in any shape, from a mold. Objects like insects or coins, or even dangerous chemicals in breakable quartz ampules, may be embedded in such "cast" blocks, for display and safe handling.
Properties
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
of 1.17–1.20 g/cm3, which is less than half that of glass. It also has good impact strength, higher than both glass and polystyrene; however, PMMA's impact strength is still significantly lower than polycarbonate and some engineered polymers. PMMA ignites at 460 °C (860 °F) and burns
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
, forming carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
, water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
, carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
and low molecular weight compounds, including formaldehyde
Formaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...
.
PMMA transmits
Transmittance
In optics and spectroscopy, transmittance is the fraction of incident light at a specified wavelength that passes through a sample. A related term is absorptance, or absorption factor, which is the fraction of radiation absorbed by a sample at a specified wavelength...
up to 92% of visible light (3 mm thickness), and gives a reflection of about 4% from each of its surfaces on account of its refractive index
Refractive index
In optics the refractive index or index of refraction of a substance or medium is a measure of the speed of light in that medium. It is expressed as a ratio of the speed of light in vacuum relative to that in the considered medium....
(1.4914 at 587.6 nm). It filters ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
(UV) light at wavelengths below about 300 nm
Nanometre
A nanometre is a unit of length in the metric system, equal to one billionth of a metre. The name combines the SI prefix nano- with the parent unit name metre .The nanometre is often used to express dimensions on the atomic scale: the diameter...
(similar to ordinary window glass). Some manufacturers add coatings or additives to PMMA to improve absorption in the 300–400 nm range. PMMA passes infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
light of up to 2800 nm and blocks IR of longer wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s up to 25000 nm. Colored PMMA varieities allow specific IR wavelengths to pass while blocking visible light
Visible spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of...
(for remote control
Remote control
A remote control is a component of an electronics device, most commonly a television set, used for operating the television device wirelessly from a short line-of-sight distance.The remote control is usually contracted to remote...
or heat sensor applications, for example).
PMMA swells and dissolves in many organic solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
s; it also has poor resistance to many other chemicals on account of its easily hydrolyzed
Hydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
groups. Nevertheless, its environmental stability is superior to most other plastics such as polystyrene and polyethylene, and PMMA is therefore often the material of choice for outdoor applications.
PMMA has maximum water absorption ratio of 0.3–0.4% by weight. Tensile strength decreases with increased water absorption. Its coefficient of thermal expansion is relatively high as (5–10)×10−5 /K.
Modification of properties
Pure poly(methyl methacrylate) homopolymer is rarely sold as an end product, since it is not optimized for most applications. Rather, modified formulations with varying amounts of other comonomers, additives, and fillers are created for uses where specific properties are required. For example,- A small amount of acrylate comonomers are routinely used in PMMA grades destined for heat processing, since this stabilizes the polymer to depolymerizationDepolymerizationDepolymerization is the process of converting a polymer into a monomer or a mixture of monomers.Thioglycolysis, thiolysis and phloroglucinolysis are reactions used to study condensed tannins by means of their depolymerisation. Thioglycolysis is also used to study lignin....
("unzipping") during processing. - Comonomers such as butyl acrylate are often added to improve impact strength.
- Comonomers such as methacrylic acid can be added to increase the glass transition temperature of the polymer for higher temperature use such as in lighting applications.
- Plasticizers may be added to improve processing properties, lower the glass transition temperature, or improve impact properties.
- Dyes may be added to give color for decorative applications, or to protect against (or filter) UV light.
- Fillers may be added to improve cost-effectiveness.
Poly(methyl acrylate)
The polymer of methyl acrylate, PMA or poly(methyl acrylate), is similar to poly(methyl methacrylate), except for the lack of methyl groups on the backbone carbon chain. PMA is a soft white rubbery material that is softer than PMMA because its long polymer chains are thinner and smoother and can more easily slide past each other.Uses
PMMA is a versatile material and has been used in a wide range of fields and applications.Transparent glass substitute
- PMMA acrylic glass is commonly used for constructing residential and commercial aquariumAquariumAn aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
s. Designers started building big aquariums when poly(methyl methacrylate) could be used. The spectacular size of both flat panels and tunnels in aquariums such as Monterey BayMonterey Bay AquariumThe Monterey Bay Aquarium is located on the former site of a sardine cannery on Cannery Row of the Pacific Ocean shoreline in Monterey, California. It has an annual attendance of 1.8 million visitors. It holds thousands of plants and animals, representing 623 separate named species on display...
, Tokyo Sea Life Park, OsakaOsaka Aquarium KaiyukanThe is an aquarium located in the ward of Minato in Osaka, Japan, near Osaka Bay. It is one of the largest public aquariums in the world, and is a member of the Japanese Association of Zoos and Aquariums ....
, Nagoya, GeorgiaGeorgia AquariumThe Georgia Aquarium, located in Atlanta, Georgia, United States, at Pemberton Place, is the world's largest aquarium with more than of marine and fresh water housing more than 120,000 animals of 500 different species...
and Dubai Aquariums were made possible with the introduction of acrylic. It is less-used in other building types due to incidents such as the Summerland disasterSummerland disasterThe Summerland disaster occurred when a fire spread through the Summerland leisure centre in Douglas on the Isle of Man on the night of 2 August 1973. 50 people were killed and 80 seriously injured.-Background:...
. - PMMA was used for the window of the bathyscaphe TriesteBathyscaphe TriesteThe Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe with a crew of two, which reached a record maximum depth of about , in the deepest known part of the Earth's oceans, the Challenger Deep, in the Mariana Trench near Guam, on January 23, 1960, crewed by Jacques Piccard ...
for all of its dives, including the record-setting dive to the bottom of the Challenger deepChallenger DeepThe Challenger Deep is the deepest known point in the oceans, with a depth of to by direct measurement from submersibles, and slightly more by sonar bathymetry . It is located at the southern end of the Mariana Trench near the Mariana Islands group...
in the Mariana TrenchMariana TrenchThe Mariana Trench or Marianas Trench is the deepest part of the world's oceans. It is located in the western Pacific Ocean, to the east of the Mariana Islands. The trench is about long but has a mean width of only...
in 1960. The conical window set into the 12.7 cm thick wall of the sphere (small end inward) was required to withstand ~ 1100 atmospheres of pressure at the bottom. - Acrylic is used for viewing ports and even complete pressure hulls of submersibles, such as the Alicia submarineAlicia (submarine)Alicia is a 6-seater submarine designed and built by Marlin Submarines of Plymouth, England. Designed for research and tourism to depths of up to , Alicia offers passengers unparalleled views by having a forward section constructed of transparent acrylic spherical sections made by Stanley...
's viewing sphere. - PMMA is used in the lenses of exterior lights of automobiles.
- The spectator protection in ice hockeyIce hockeyIce hockey, often referred to as hockey, is a team sport played on ice, in which skaters use wooden or composite sticks to shoot a hard rubber puck into their opponent's net. The game is played between two teams of six players each. Five members of each team skate up and down the ice trying to take...
rinks is made from PMMA. - It is used in motorcycle helmetMotorcycle helmetA motorcycle helmet is a type of protective headgear used by motorcycle riders. The primary goal of a motorcycle helmet is motorcycle safety - to protect the rider's head during impact, thus preventing or reducing head injury or saving the rider's life...
visors - Historically, PMMA was an important improvement in the design of aircraft windows, making possible such iconic designs as the bombadier's transparent nose compartment in the Boeing B-17 Flying Fortress.
- Polycast acrylic sheet is the most widely used material in aircraft transparencies (windows). In applications where the aircraft is pressurized, stretched acrylic is used. Only in the most advanced modern fighter jets, such as the F-22 RaptorF-22 RaptorThe Lockheed Martin/Boeing F-22 Raptor is a single-seat, twin-engine fifth-generation supermaneuverable fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack, electronic warfare, and signals...
, has traditional acrylic been replaced by polycarbonatePolycarbonatePolycarbonatePhysical PropertiesDensity 1.20–1.22 g/cm3Abbe number 34.0Refractive index 1.584–1.586FlammabilityV0-V2Limiting oxygen index25–27%Water absorption – Equilibrium0.16–0.35%Water absorption – over 24 hours0.1%...
(Lexan). - Police vehiclesPolice carA police car is a ground vehicle used by police, to assist with their duties in patrolling and responding to incidents. Typical uses of a police car include transportation for officers to reach the scene of an incident quickly, to transport criminal suspects, or to patrol an area, while providing a...
for riot controlRiot controlRiot control refers to the measures used by police, military, or other security forces to control, disperse, and arrest civilians who are involved in a riot, demonstration, or protest. Law enforcement officers or soldiers have long used non-lethal weapons such as batons and whips to disperse crowds...
often have the regular glass replaced with acrylic to protect the occupants from thrown objects. - Acrylic is an important material in the making of certain lighthouse lenses.
- Acrylic is also used to make infra-red receptors tamper-proof. Infra red radiation can travel through acrylic material, but its use prevents physical damage to the sensor.
- PMMA was used (called Oroglas in this instance) instead of glass in the fated SummerlandSummerland-Places:* Summerland, British Columbia, a Canadian town* Summerlands, Victoria, an Australian town* Summerland, California, USA, an unincorporated community near Santa Barbara* Summerland Key, an island in the Florida Keys in the United States...
built on the Isle Of Man in 1971, it was destroyed by fire in 1973 and the PMMA sheets used for the promenade wall was partially blamed for the rapid spread of the fire.
Daylight redirection
- Laser cut acrylic panels have been used to redirect sunlight into a light pipe or tubular skylight and, from there, to spread it into a room. Their developers Veronica Garcia Hansen, Ken YeangKen YeangDr. Ken Yeang [Chinese]: 杨经文/楊經文; [pinyin]: Yáng Jīngwén; born 1948) is a prolific Malaysian architect and writer best known for advancing green design and planning, differentiated from other green architects by his comprehensive ecological approach....
, and Ian Edmonds were awarded the Far East Economic Review Innovation Award in bronze for this technology in 2003. - Attenuation being quite strong for distances over one meter (more than 90% intensity loss for a 3000 K source), acrylic broadband light guides are then dedicated mostly to decorative uses.
- Pairs of acrylic sheets with a layer of microreplicated prisms between the sheets can have reflective and refractive properties that let them redirect part of incoming sunlight in dependence on its angle of incidenceAngle of incidenceAngle of incidence is a measure of deviation of something from "straight on", for example:* in the approach of a ray to a surface, or* the angle at which the wing or horizontal tail of an airplane is installed on the fuselage, measured relative to the axis of the fuselage.-Optics:In geometric...
. Such panels act as miniature light shelvesArchitectural light shelfA light shelf is an architectural element that allows daylight to penetrate deep into a building. This horizontal light-reflecting overhang is placed above eye-level and has a high-reflectance upper surface...
. Such panels have been commercialized for purposes of daylightingDaylightingDaylighting is the practice of placing windows or other openings and reflective surfaces so that during the day natural light provides effective internal lighting. Particular attention is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy...
, to be used as a windowWindowA window is a transparent or translucent opening in a wall or door that allows the passage of light and, if not closed or sealed, air and sound. Windows are usually glazed or covered in some other transparent or translucent material like float glass. Windows are held in place by frames, which...
or a canopyCanopy (building)A canopy is an overhead roof or else a structure over which a fabric or metal covering is attached, able to provide shade or shelter. A canopy can also be a tent, generally without a floor....
such that sunlight descending from the sky is directed to the ceiling or into the room rather than to the floor. This can lead to a higher illumination of the back part of a room, in particular when combined with a white ceiling, while having a slight impact on the view to the outside compared to normal glazing.
Medical technologies and implants
- PMMA has a good degree of compatibility with human tissueTissue (biology)Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
, and can be used for replacement intraocular lensIntraocular lensAn intraocular lens is an implanted lens in the eye, usually replacing the existing crystalline lens because it has been clouded over by a cataract, or as a form of refractive surgery to change the eye's optical power. It usually consists of a small plastic lens with plastic side struts, called...
es in the eyeHuman eyeThe human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
when the original lens has been removed in the treatment of cataractCataractA cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light...
s. This compatibility was discovered in WWII RAF pilots, whose eyes had been riddled with PMMA splinters coming from the side windows of their Supermarine Spitfire fighters – the plastic scarcely caused any rejection, compared to glass splinters coming from aircraft such as the Hawker HurricaneHawker HurricaneThe Hawker Hurricane is a British single-seat fighter aircraft that was designed and predominantly built by Hawker Aircraft Ltd for the Royal Air Force...
. Historically, hard contact lensContact lensA contact lens, or simply contact, is a lens placed on the eye. They are considered medical devices and can be worn to correct vision, for cosmetic or therapeutic reasons. In 2004, it was estimated that 125 million people use contact lenses worldwide, including 28 to 38 million in the United...
es were frequently made of this material. Soft contact lenses are often made of a related polymer, where acrylate monomers containing one or more hydroxyl groupHydroxylA hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...
s make them hydrophilicHydrophileA hydrophile, from the Greek "water" and φιλια "love," is a molecule or other molecular entity that is attracted to, and tends to be dissolved by water. A hydrophilic molecule or portion of a molecule is one that has a tendency to interact with or be dissolved by, water and other polar substances...
. - In orthopedic surgeryOrthopedic surgeryOrthopedic surgery or orthopedics is the branch of surgery concerned with conditions involving the musculoskeletal system...
, PMMA bone cementBone cementBone cements have been used very successfully to anchor artificial joints for more than half a century. Artificial joints are anchored with bone cement. The bone cement fills the free space between the prosthesis and the bone and plays the important role of an elastic zone...
is used to affix implants and to remodel lost bone. It is supplied as a powder with liquid methyl methacrylate (MMA). When mixed these yield a dough-like cement that gradually hardens. Surgeons can judge the curing of the PMMA bone cement by pressing their thumb on it. Although PMMA is biologically compatible, MMA is considered to be an irritant and a possible carcinogenCarcinogenA carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
. PMMA has also been linked to cardiopulmonaryCardiopulmonary resuscitationCardiopulmonary resuscitation is an emergency procedure which is performed in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest. It is indicated in those who are unresponsive...
events in the operating room due to hypotensionHypotensionIn physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
. Bone cement acts like a groutGroutGrout is a construction material used to embed rebars in masonry walls, connect sections of pre-cast concrete, fill voids, and seal joints . Grout is generally composed of a mixture of water, cement, sand, often color tint, and sometimes fine gravel...
and not so much like a glue in arthroplastyArthroplastyArthroplasty is an operative procedure of orthopedic surgery performed, in which the arthritic or dysfunctional joint surface is replaced with something better or by remodeling or realigning the joint by osteotomy or some other procedure.-Background:Previously, a popular form of arthroplasty was...
. Although sticky, it does not bond to either the bone or the implant, it primarily fills the spaces between the prosthesis and the bone preventing motion. A big disadvantage to this bone cement is that it heats to quite a high temperature while setting, potentially 82.5 deg C and because of this, thermal necrosis of neighboring tissue can potentially result. A careful balance of initiators and monomers is needed to reduce the rate of polymerisation, and thus the heat generated. A major consideration when using PMMA cement is the effect of stress shieldingStress shieldingStress shielding refers to the reduction in bone density as a result of removal of normal stress from the bone by an implant . This is because by Wolff's law, bone in a healthy person or animal will remodel in response to the loads it is placed under...
. Since PMMA has a Young's modulusYoung's modulusYoung's modulus is a measure of the stiffness of an elastic material and is a quantity used to characterize materials. It is defined as the ratio of the uniaxial stress over the uniaxial strain in the range of stress in which Hooke's Law holds. In solid mechanics, the slope of the stress-strain...
greater than that of natural bone, the stresses are loaded into the cement and so the bone no longer receives the mechanical signals to continue bone remodelingBone remodelingBone remodeling is a lifelong process where mature bone tissue is removed from the skeleton and new bone tissue is formed...
and so resorption will occur. - DenturesDenturesDentures are prosthetic devices constructed to replace missing teeth, and which are supported by surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable, however there are many different denture designs, some which rely on bonding or clasping onto teeth or dental...
are often made of PMMA, and can be color-matched to the patient's teeth & gum tissue. PMMA is also used in the production of ocular prostheses. - In cosmetic surgeryPlastic surgeryPlastic surgery is a medical specialty concerned with the correction or restoration of form and function. Though cosmetic or aesthetic surgery is the best-known kind of plastic surgery, most plastic surgery is not cosmetic: plastic surgery includes many types of reconstructive surgery, hand...
, tiny PMMA microspheres suspended in some biological fluid are injected under the skin to reduce wrinkles or scars permanently. - A large majority of white Dental filling materials (i.e. composites) have PMMA as their main organic component.
- Emerging biotechnology and Biomedical research uses PMMA to create microfluidicMicrofluidicsMicrofluidics deals with the behavior, precise control and manipulation of fluids that are geometrically constrained to a small, typically sub-millimeter, scale.Typically, micro means one of the following features:* small volumes...
lab-on-a-chipLab-on-a-chipA lab-on-a-chip is a device that integrates one or several laboratory functions on a single chip of only millimeters to a few square centimeters in size. LOCs deal with the handling of extremely small fluid volumes down to less than pico liters. Lab-on-a-chip devices are a subset of MEMS devices...
devices, which require 100 micrometre-wide geometries for routing liquids. These small geometries are amenable to using PMMA in a biochipBiochipThe development of biochips is a major thrust of the rapidly growing biotechnology industry, which encompasses a very diverse range ofresearch efforts including genomics, proteomics, and pharmaceuticals, among other activities...
fabrication process and offers moderate biocompatibilityBiocompatibilityBiocompatibility is related to the behavior of biomaterials in various contexts. The term may refer to specific properties of a material without specifying where or how the material is used , or to more empirical clinical success of a whole device in...
. - BioprocessBioprocessA bioprocess is any process that uses complete living cells or their components to obtain desired productsTransport of energy and mass is fundamental to many biological and environmental processes...
chromatographyChromatographyChromatography is the collective term for a set of laboratory techniques for the separation of mixtures....
columns use cast acrylic tubes as an alternative to glass and stainless steel. These are pressure rated and satisfy stringent requirements of materials for biocompatibilityBiocompatibilityBiocompatibility is related to the behavior of biomaterials in various contexts. The term may refer to specific properties of a material without specifying where or how the material is used , or to more empirical clinical success of a whole device in...
, toxicity and extractables.
Artistic and aesthetic uses
- Acrylic paintAcrylic paintAcrylic paint is fast drying paint containing pigment suspension in acrylic polymer emulsion. Acrylic paints can be diluted with water, but become water-resistant when dry...
essentially consists of PMMA suspended in water; however since PMMA is hydrophobicHydrophobeIn chemistry, hydrophobicity is the physical property of a molecule that is repelled from a mass of water....
, a substance with both hydrophobic and hydrophilic groups needs to be added to facilitate the suspensionSuspension (chemistry)In chemistry, a suspension is a heterogeneous fluid containing solid particles that are sufficiently large for sedimentation. Usually they must be larger than 1 micrometer. The internal phase is dispersed throughout the external phase through mechanical agitation, with the use of certain...
. - Modern furnitureFurnitureFurniture is the mass noun for the movable objects intended to support various human activities such as seating and sleeping in beds, to hold objects at a convenient height for work using horizontal surfaces above the ground, or to store things...
makers, especially in the 1960s and 1970s, seeking to give their products a space age aesthetic, incorporated Lucite and other PMMA products into their designs, especially office chairs. Many other products (for example, guitars) are sometimes made with acrylic glass to make the commonly opaque objects translucent. - Perspex has been used as a surface to paint on, for example by Salvador DalíSalvador DalíSalvador Domènec Felip Jacint Dalí i Domènech, Marquis de Púbol , commonly known as Salvador Dalí , was a prominent Spanish Catalan surrealist painter born in Figueres,Spain....
. - DiasecDiasecDiasec is a patented process used for facemounting prints like photographs on acrylic glass. The process was invented by Heinz Sovilla-Brulhart in 1969....
is a process which uses acrylic glass as a substitute for normal glass in picture framingPicture frameA picture frame is a decorative edging for a picture, such as a painting or photograph, intended to enhance it, make it easier to display, or protect it.-Construction:...
. This is done for its relatively low cost, light weight, shatter-resistance, aesthetics and because it can be ordered in larger sizes than standard picture framing glassPicture framing glassPicture framing glass usually refers to flat glass or acrylic used for framing artwork and for presenting art objects in a display box .-Purpose:...
. - From approximately the 1960s onward, sculptors and glass artists such as Leroy LamisLeroy LamisLeroy Lamis was an American sculptor, digital artist and art educator known for his work with Plexiglas. His works have been exhibited throughout the United States and Europe and are in the permanent collections of numerous institutions including the Whitney Museum of American Art and the...
began using acrylics, especially taking advantage of the material's flexibility, light weight, cost and its capacity to refract and filter light. - In the 1950s and 1960s, Lucite was an extremely popular material for jewelry, with several companies specialized in creating high-quality pieces from this material. Lucite beads and ornaments are still sold by jewelry suppliers.
Other uses
- Sheets of PMMA are commonly used in the sign industry to make flat cut out letters in thicknesses typically varying from 3 to 25 mm (0.118110236220472 to 0.984251968503937 in). These letters may be used alone to represent a company's name and/or logo, or they may be a component of channel letters which are neon or LEDLight-emitting diodeA light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...
illuminated. Acrylic's attractiveness, durability and resistance to warping make it an ideal interior and exterior sign material. Acrylic is also used extensively throughout the sign industry as a component of wall signs where it may be a backplate, painted on the surface or the backside, a faceplate with additional raised lettering or even photographic images printed directly to it, or a spacer to separate sign components. One of the most popular sheets is a non-glare, translucent which is sold in 1.6 millimetre (0.062992125984252 in) or 3 millimetre (0.118110236220472 in) in thicknesses. - PMMA was used in laserdiscLaserdiscLaserDisc was a home video format and the first commercial optical disc storage medium. Initially licensed, sold, and marketed as MCA DiscoVision in North America in 1978, the technology was previously referred to interally as Optical Videodisc System, Reflective Optical Videodisc, Laser Optical...
optical media. (CDCompact DiscThe Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...
s and DVDDVDA DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....
s use both acrylic and polycarbonate for higher impact resistance.) - It is used as a light guide for the backlights in TFT-LCDsTFT LCDThin film transistor liquid crystal display is a variant of liquid crystal display which uses thin-film transistor technology to improve image quality . TFT LCD is one type of Active matrix LCD, though all LCD-screens are based on TFT active matrix addressing...
. - Plastic optical fiberPlastic optical fiberPlastic optical fiber is an optical fiber which is made out of plastic. Traditionally PMMA is the core material, and fluorinated polymers are the cladding material...
used for short distance communication is made from PMMA, and perfluorinated PMMA, clad with fluorinated PMMA, in situations where its flexibility and cheaper installation costs outweigh its poor heat tolerance and higher attenuation over glass fiber. - PMMA, in a purified form, is used as the matrix in laser dyeLaser dyeLaser dyes are very large organic molecules with molecular weights of a few hundred mu. When one of these organic molecules is dissolved in a suitable liquid solvent it can be used as gain medium in a dye laser. Laser dye solutions absorb at shorter wavelengths end emit at longer wavelengths...
-doped solid-state gain media for solid state dye lasersSolid state dye lasersSolid state dye lasers were introduced in 1967 by Soffer and McFarland. In these solid state lasers, the gain medium is a laser dye-doped organic matrix such as poly , rather than a liquid solution of the dye...
. - In semiconductorSemiconductorA semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
research and industry, PMMA aids as a resistResistIn semiconductor fabrication, a resist is a thin layer used to transfer a circuit pattern to the semiconductor substrate which it is deposited upon. A resist can be patterned via lithography to form a micrometer-scale, temporary mask that protects selected areas of the underlying substrate during...
in the electron beam lithographyElectron beam lithographyElectron beam lithography is the practice of emitting a beam of electrons in a patterned fashion across a surface covered with a film , and of selectively removing either exposed or non-exposed regions of the resist...
process. A solution consisting of the polymer in a solvent is used to spin coatSpin coatingSpin coating is a procedure used to apply uniform thin films to flat substrates. In short, an excess amount of a solution is placed on the substrate, which is then rotated at high speed in order to spread the fluid by centrifugal force...
siliconSiliconSilicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...
and other semiconducting and semi-insulating wafers with a thin film. Patterns on this can be made by an electron beam (using an electron microscopeElectron microscopeAn electron microscope is a type of microscope that uses a beam of electrons to illuminate the specimen and produce a magnified image. Electron microscopes have a greater resolving power than a light-powered optical microscope, because electrons have wavelengths about 100,000 times shorter than...
), deep UV light (shorter wavelength than the standard photolithographyPhotolithographyPhotolithography is a process used in microfabrication to selectively remove parts of a thin film or the bulk of a substrate. It uses light to transfer a geometric pattern from a photomask to a light-sensitive chemical "photoresist", or simply "resist," on the substrate...
process), or X-rayX-rayX-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
s. Exposure to these creates chain scission or (de-cross-linkCross-linkCross-links are bonds that link one polymer chain to another. They can be covalent bonds or ionic bonds. "Polymer chains" can refer to synthetic polymers or natural polymers . When the term "cross-linking" is used in the synthetic polymer science field, it usually refers to the use of...
ing) within the PMMA, allowing for the selective removal of exposed areas by a chemical developer, making it a positive photoresist. PMMA's advantage is that it allows for extremely high resolution (nanoscale) patterns to be made. It is an invaluable tool in nanotechnologyNanotechnologyNanotechnology is the study of manipulating matter on an atomic and molecular scale. Generally, nanotechnology deals with developing materials, devices, or other structures possessing at least one dimension sized from 1 to 100 nanometres...
. Smooth PMMA surface can be easily nanostructured by treatment in oxygen radio-frequency plasma and nanostructured PMMA surface can be easily smoothed by vacuum ultraviolet (VUV) irradiation. - PMMA is used as a shield to stop beta radiation emitted from radioisotopes.
- Small strips of PMMA are used as dosimeterDosimeterDosimeters measure an individual's or an object'sexposure to something in the environment — particularly to a hazard inflicting cumulative impact over long periods of time, or over a lifetime...
devices during the GammaGammaGamma is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. It was derived from the Phoenician letter Gimel . Letters that arose from Gamma include the Roman C and G and the Cyrillic letters Ge Г and Ghe Ґ.-Greek:In Ancient Greek, gamma represented a...
Irradiation process. The optical density of PMMA changes as the Gamma dose increases and can be measured with a spectrophotometerSpectrophotometryIn chemistry, spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength...
. - Recently a blacklightBlack lightA black light, also referred to as a UV light, ultraviolet light, or Wood's lamp, is a lamp that emits ultraviolet radiation in the long-wave range, and little visible light...
-reactive tattooTattooA tattoo is made by inserting indelible ink into the dermis layer of the skin to change the pigment. Tattoos on humans are a type of body modification, and tattoos on other animals are most commonly used for identification purposes...
inkInkInk is a liquid or paste that contains pigments and/or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing and/or writing with a pen, brush, or quill...
using PMMA microcapsuleMicro-encapsulationMicro-encapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules many useful properties. In a relatively simplistic form, a microcapsule is a small sphere with a uniform wall around it...
s was developed. This ink is reportedly safe for use, and claims to be Food and Drug Administration (FDA) approved for use on wildlife that may enter the food supply. - PMMA can be used as a dispersantDispersantA dispersant or a dispersing agent or a plasticizer or a superplasticizer is either a non-surface active polymer or a surface-active substance added to a suspension, usually a colloid, to improve the separation of particles and to prevent settling or clumping...
for ceramic powders to stabilize colloidal suspensions in non-aqueous mediums. - PMMA has also been used extensively as a hybrid rocketHybrid rocketA hybrid rocket is a rocket with a rocket motor which uses propellants in two different states of matter - one solid and the other either gas or liquid. The Hybrid rocket concept can be traced back at least 75 years....
fuel. - In the 1960s, luthierLuthierA luthier is someone who makes or repairs lutes and other string instruments. In the United States, the term is used interchangeably with a term for the specialty of each maker, such as violinmaker, guitar maker, lute maker, etc...
Dan ArmstrongDan ArmstrongDan Armstrong was a guitarist, luthier, and session musician.-Biography:Dan Kent Armstrong was born on October 7, 1934 in Pittsburgh, Pennsylvania. He started playing the guitar at age 11, and moved to New York in the early 1960s in order to work as a studio musician and guitar repairman...
developed a line of electric guitars and basses whose bodies were made completely of acrylic. These instruments were marketed under the AmpegAmpegAmpeg is primarily a musical instrument amplifier manufacturer headquartered in Woodinville, Washington, though they also manufacture guitars to a small extent...
brand. IbanezIbanezis a Japanese guitar brand owned by Hoshino Gakki. Based in Nagoya, Aichi, Japan, Hoshino Gakki were one of the first Japanese musical instrument companies to gain a significant foothold in import guitar sales in the United States and Europe, as well as the first brand of guitars to mass produce...
and B.C. RichB.C. RichB.C. Rich is a manufacturer of guitars and bass guitars founded by the late Bernardo Chavez Rico in 1969. Currently, most B.C. Rich guitars are manufactured in Asia, but luthiers of the company's custom shop continue to hand-make instruments. The Hanser Music Group, based in Kentucky, operates B.C....
have also made acrylic guitars. - Ludwig-MusserLudwig-MusserLudwig-Musser is a drum and percussion instrument manufacturer that is part of the Conn-Selmer division of Steinway Musical Instruments.The first product made by the Ludwig brothers, William and Theobaldner , was a bass drum pedal capable of playing faster beats than was typical of products of the...
makes a line of acrylic drums called Vistalites, well known as being used by Led ZeppelinLed ZeppelinLed Zeppelin were an English rock band, active in the late 1960s and throughout the 1970s. Formed in 1968, they consisted of guitarist Jimmy Page, singer Robert Plant, bassist/keyboardist John Paul Jones, and drummer John Bonham...
drummer John BonhamJohn BonhamJohn Henry Bonham was an English musician and songwriter, best known as the drummer of Led Zeppelin. Bonham was esteemed for his speed, power, fast right foot, distinctive sound, and "feel" for the groove...
. - Artificial fingernails are sometimes made of acrylic.
- Some modern briar, and occasionally meerschaum, tobacco pipes sport stems made of Lucite, although the vast majority of stems for such pipes are still made with the traditional vulcanized rubber.
- PMMA technology is utilized in roofing and waterproofing applications. By incorporating a polyester fleece sandwiched between two layers of catalyst-activated PMMA resin, a fully reinforced liquid membrane is created in situ. Such a membrane construction is flexible while also being tear and puncture resistant.