POLYMETHYL METHACRYLATE

POLYMETHYL METHACRYLATE

Polymethyl methacrylate (PMMA) is the synthetic polymer derived from methyl methacrylate. 
Being an engineering plastic, Polymethyl methacrylate is a transparent thermoplastic. 
Polymethyl methacrylate is also known as acrylic, acrylic glass. 
Polymethyl methacrylate can also be used as a casting resin, in inks and coatings, and for many other purposes.

Polymethyl methacrylate is often technically classified as a type of glass, in that it is a non-crystalline vitreous substance—hence its occasional historic designation as acrylic glass.

CAS: 9011-14-7
European Community (EC) Number: 201-297-1

Density (lb/in³): 0.043
(g/cm³): 1.18

Specific Gravity (water=1): 1.18-1.2

Polymethyl methacrylate is a transparent material. 
Polymethyl methacrylate is also known as acrylic or acrylic glass. 
Polymethyl methacrylate is a rigid thermoplastic widely used as a shatterproof replacement for glass. 
Polymethyl methacrylate has many technical advantages over other transparent polymers (PC and PS) such as:

-High resistance to UV light and weathering
-Excellent light transmission
-Unlimited coloring options

Polymethyl methacrylate or poly (methyl 2‐methylpropenoate) is produced from the monomer methyl methacrylate.

Polymethyl methacrylate is a clear, colorless polymer available in pellet, small granules, and sheet forms. 
They are then formed with all thermoplastic methods including injection molding, compression molding, and extrusion. 
The highest quality PMMA sheets are produced by cell casting, but in this case, the polymerization and molding steps occur concurrently. 
Polymethyl methacrylate is commonly called acrylic glass.

The strength of the material is higher than molding grades owing to its extremely high molecular mass. 
Rubber toughening has been used to increase the toughness of PMMA owing to its brittle behavior in response to applied loads. 
PMMA is 100% recyclable.

Polymethyl methacrylate or PMMA is more popularly known as acrylic. 
Polymethyl methacrylate is a transparent and rigid thermoplastic. It is produced from the monomer methyl methacrylate. 
Polymethyl methacrylate shows high resistance to UV light and weathering. 
Due to its transparency, PMMA is used in car windows, smartphone screens to aquariums. 
Polymethyl methacrylate is a tough plastic, easy to shape, and a great alternative to the high-cost and less resilient glass. 
Polymethyl methacrylate is a cost-effective alternative to polycarbonate when desired properties are tensile strength, flexural strength, and transparency.

Polymethyl methacrylate, a synthetic resin produced from the polymerization of methyl methacrylate. 
A transparent and rigid plastic, PMMA is often used as a substitute for glass in products such as shatterproof windows, skylights, illuminated signs, and aircraft canopies. 

Polymethyl methacrylate, an ester of methacrylic acid (CH2=C[CH3]CO2H), belongs to the important acrylic family of resins. 
In modern production it is obtained principally from propylene, a compound refined from the lighter fractions of crude oil. 
Propylene and benzene are reacted together to form cumene, or isopropylbenzene; the cumene is oxidized to cumene hydroperoxide, which is treated with acid to form acetone; the acetone is in turn converted in a three-step process to methyl methacrylate (CH2=C[CH3]CO2CH3), a flammable liquid. 
Methyl methacrylate, in bulk liquid form or suspended as fine droplets in water, is polymerized (its molecules linked together in large numbers) under the influence of free-radical initiators to form solid PMMA. 

Common orthographic stylings include polymethyl methacrylate and polymethylmethacrylate. 
The full IUPAC chemical name is poly(methyl 2-methylpropenoate). 

The presence of the pendant methyl (CH3) groups prevents the polymer chains from packing closely in a crystalline fashion and from rotating freely around the carbon-carbon bonds. 
As a result, Polymethyl methacrylate is a tough and rigid plastic. 
In addition, it has almost perfect transmission of visible light, and, because it retains these properties over years of exposure to ultraviolet radiation and weather, it is an ideal substitute for glass. 
A most successful application is in internally lighted signs for advertising and directions. 
PMMA is also employed in domed skylights, swimming pool enclosures, aircraft canopies, instrument panels, and luminous ceilings. 
For these applications the plastic is drawn into sheets that are machined or thermoformed, but it is also injection-molded into automobile lenses and lighting-fixture covers.
Because Polymethyl methacrylate displays the unusual property of keeping a beam of light reflected within its surfaces, it is frequently made into optical fibres for telecommunication or endoscopy.

Synthesis

Polymethyl methacrylate is routinely produced by emulsion polymerization, solution polymerization, and bulk polymerization. 
Generally, radical initiation is used (including living polymerization methods), but anionic polymerization of PMMA can also be performed.

Processing

The glass transition temperature (Tg) of atactic Polymethyl methacrylate is 105 °C (221 °F). 
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 that are copolymers with co-monomers other than methyl methacrylate. PMMA is thus an organic glass at room temperature.
The forming temperature starts at the glass transition temperature and goes up from there.
All common molding processes may be used, including injection molding, compression molding, and extrusion. 
The highest quality PMMA sheets are produced by cell casting, 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. 
Rubber toughening has been used to increase the toughness of PMMA to overcome its brittle behavior in response to applied loads.

Handling, cutting, and joining

Polymethyl methacrylate can be joined using cyanoacrylate cement (commonly known as superglue), with heat (welding), or by using chlorinated solvents such as dichloromethane or trichloromethane (chloroform) 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 may be used to form intricate designs from PMMA sheets. 
Polymethyl methacrylate 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 high internal stresses, which on exposure to solvents produce 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.

In the majority of applications, it will not shatter. 
Rather, it breaks into large dull pieces. 
Since Polymethyl methacrylate is softer and more easily scratched than glass, scratch-resistant coatings are often added to PMMA sheets to protect it (as well as possible other functions).

Acrylate resin casting

Methyl methacrylate "synthetic resin" for casting (simply the bulk liquid chemical) may be used in conjunction with a polymerization catalyst such as methyl ethyl ketone peroxide (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

Polymethyl methacrylate is a strong, tough, and lightweight material. 
Polymethyl methacrylate has a density of 1.17–1.20 g/cm3, which is less than half that of glass.
Polymethyl methacrylate 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. 
Polymethyl methacrylate ignites at 460 °C (860 °F) and burns, forming carbon dioxide, water, carbon monoxide, and low-molecular-weight compounds, including formaldehyde.

Polymethyl methacrylate transmits up to 92% of visible light (3 mm thickness), and gives a reflection of about 4% from each of its surfaces due to its refractive index (1.4905 at 589.3 nm).
Polymethyl methacrylate filters ultraviolet (UV) light at wavelengths below about 300 nm (similar to ordinary window glass). 
Some manufacturers add coatings or additives to PMMA to improve absorption in the 300–400 nm range. 
Polymethyl methacrylate passes infrared light of up to 2,800 nm and blocks IR of longer wavelengths up to 25,000 nm. 
Colored Polymethyl methacrylate varieties allow specific IR wavelengths to pass while blocking visible light (for remote control or heat sensor applications, for example).

Polymethyl methacrylate swells and dissolves in many organic solvents; it also has poor resistance to many other chemicals due to its easily hydrolyzed ester groups. 
Nevertheless, its environmental stability is superior to most other plastics such as polystyrene and polyethylene, and therefore it is often the material of choice for outdoor applications.

Polymethyl methacrylate has a maximum water absorption ratio of 0.3–0.4% by weight.
Tensile strength decreases with increased water absorption.
Polymethyl methacrylate's coefficient of thermal expansion is relatively high at (5–10)×10−5 °C−1.

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 depolymerization ("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, improve impact properties, and improve mechanical properties such as elastic modulus

-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.

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.
Polymethyl methacrylate 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
Being transparent and durable, Polymethyl methacrylate is a versatile material and has been used in a wide range of fields and applications such as rear-lights and instrument clusters for vehicles, appliances, and lenses for glasses. 
Polymethyl methacrylate in the form of sheets affords to shatter resistant panels for building windows, skylights, bulletproof security barriers, signs & displays, sanitary ware (bathtubs), LCD screens, furniture and many other applications. 
Polymethyl methacrylate is also used for coating polymers based on MMA provides outstanding stability against environmental conditions with reduced emission of VOC. 
Methacrylate polymers are used extensively in medical and dental applications where purity and stability are critical to performance.

Transparent glass substitute

Polymethyl methacrylate is commonly used for constructing residential and commercial aquariums. 
Designers started building large aquariums when poly(methyl methacrylate) could be used. 

Polymethyl methacrylate is used for viewing ports and even complete pressure hulls of submersibles, such as the Alicia submarine's viewing sphere and the window of the bathyscaphe Trieste.

Polymethyl methacrylate is used in the lenses of exterior lights of automobiles.

Spectator protection in ice hockey rinks is made from Polymethyl methacrylate.

Historically, Polymethyl methacrylate was an important improvement in the design of aircraft windows, making possible such designs as the bombardier's transparent nose compartment in the Boeing B-17 Flying Fortress. 

Modern aircraft transparencies often use stretched acrylic plies.

Police vehicles for riot control often have the regular glass replaced with PMMA to protect the occupants from thrown objects.

Polymethyl methacrylate is an important material in the making of certain lighthouse lenses.

Polymethyl methacrylate was used for the roofing of the compound in the Olympic Park for the 1972 Summer Olympics in Munich. 
Polymethyl methacrylate enabled a light and translucent construction of the structure.

Polymethyl methacrylate was used for the ceiling of the Houston Astrodome.

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 Yeang, 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 incidence. 
Such panels act as miniature light shelves. 
Such panels have been commercialized for purposes of daylighting, to be used as a window or a canopy 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
Polymethyl methacrylate has a good degree of compatibility with human tissue, and it is used in the manufacture of rigid intraocular lenses which are implanted in the eye when the original lens has been removed in the treatment of cataracts. 
This compatibility was discovered by the English ophthalmologist Harold Ridley in WWII RAF pilots, whose eyes had been riddled with Polymethyl methacrylate 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 Hurricane.

On 29 November 1949 at St Thomas' Hospital, London, Ridley implanted the first intraocular lens at St Thomas's Hospital in London.

SYNONYMS:

METHYL METHACRYLATE
80-62-6
methyl 2-methylprop-2-enoate
Methylmethacrylate
Methyl methylacrylate
Methyl 2-methylpropenoate
Methacrylic acid methyl ester
Pegalan
Methyl-methacrylat
Methyl 2-methyl-2-propenoate
Diakon
Acryester M
2-Propenoic acid, 2-methyl-, methyl ester
Methacrylate de methyle
Methyl 2-methylacrylate
2-Methyl-2-propenoic acid methyl ester
Methacrylsaeuremethyl ester
2-(Methoxycarbonyl)-1-propene
Metakrylan metylu
Methylmethacrylaat
Metil metacrilato
Rcra waste number U162
Methyl alpha-methylacrylate
Methyl methacrylate monomer
TEB 3K
NCI-C50680
2-Methylacrylic acid, methyl ester
Methacrylic acid, methyl ester
Acrylic acid, 2-methyl-, methyl ester
2-Methyl-acrylic acid methyl ester
NSC 4769
9011-14-7
Monocite methacrylate monomer
Methylester kyseliny methakrylove
CHEBI:34840
2-methylacrylic acid methyl ester
Methyl meth-d3-acrylate
Methyl .alpha.-methylacrylate
Cranioplast
DTXSID2020844
Metaplex
Kallocryl A
NSC-4769
Simplex P
Methyl methacrylate monomer, inhibited
143476-91-9
Methyl ester of 2-methyl-2-propenoic acid
196OC77688
114512-63-9
Plexiglass
Methylmethacrylaat [Dutch]
Metakrylan metylu [Polish]
Methyl-methacrylat [German]
Metil metacrilato [Italian]
51391-19-6
55063-97-3
CCRIS 1364
HSDB 195
Methacrylate de methyle [French]
Methacrylsaeuremethyl ester [German]
EINECS 201-297-1
UN1247
RCRA waste no. U162
BRN 0605459
Eudragit
Methylester kyseliny methakrylove [Czech]
AI3-24946
methoxymethacrolein
UNII-196OC77688
MMA (stabilized)
J69
Acrylic resins (PMMA)
METHYL METHACTRYLATE
Epitope ID:131321
Methyl 2-methylacrylate #
Methyl methacrylate (MMA)
EC 201-297-1
Methyl-.alpha.-methacrylate
SCHEMBL1849
CH2=C(CH3)COOCH3
Methacrylic acid-methyl ester
4-02-00-01519 (Beilstein Handbook Reference)
NA 1247 (Salt/Mix)
UN 1247 (Salt/Mix)
BIDD:ER0634
CHEMBL49996
DTXCID80844
Methyl methacrylate, 99.5%
WLN: 1UY1&VO1
Methyl methacrylate, stabilized
Methyl methacrylate, CP,98.0%
NSC4769
METHYL METHACRYLATE [HSDB]
METHYL METHACRYLATE [IARC]
METHYL METHACRYLATE [INCI]
METHYLMETHACRYLATE [MART.]
METHYL METHACRYLATE [VANDF]
METHYLMETHACRYLATE [WHO-DD]
Tox21_200367
MFCD00008587
STL283952
AKOS000120216
Methyl methacrylate, 99%, stabilized
CAS-80-62-6
NCGC00091089-01
NCGC00091089-02
NCGC00257921-01
9065-11-6
Methacrylic Acid Methyl Ester (stabilized
METHACRYLIC ACID METHYL ESTER [MI]
DB-013559
M0087
METHYL 2-METHYL-2-PROPENOATE [FHFI]
EN300-19210
C19504
Methyl methacrylate 1000 microg/mL in Methanol
Methyl methacrylate, SAJ first grade, >=99.0%
A839957
Q382897
J-522614
F0001-2087
Methacrylic acid-methyl ester 100 microg/mL in Cyclohexane
Methyl Methacrylate (stabilized with 6-tert-Butyl-2,4-xylenol)
Methyl Methacrylate, (stabilized with 6-tert-Butyl-2,4-xylenol)
Methyl methacrylate, contains <=30 ppm MEHQ as inhibitor, 99%
Methyl methacrylate, European Pharmacopoeia (EP) Reference Standard
Methyl methacrylate (MMA), 99.5%(GC), contains 30ppm MEHQ as stabilizer
Methyl methacrylate (MMA), AR, 99.0%, contains 30ppm MEHQ as stabilizer
Methyl methacrylate monomer, inhibited [UN1247] [Flammable liquid]
PROPENOIC ACID,2-METHYL,METHYLESTER (METHACRYLATE METHYLESTER)
97555-82-3