Polymethylmethacrylate
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| Names | |
|---|---|
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IUPAC name
Poly(methyl 2-methylpropenoate)
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| Other names
Poly(methyl methacrylate) (PMMA)
methyl methacrylate resin |
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| Identifiers | |
9011-14-7 
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| 3D model (Jmol) | Interactive image |
| ECHA InfoCard | 100.112.313 |
| KEGG |
C19504 
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| Properties | |
| (C5O2H8)n | |
| Molar mass | varies |
| Density | 1.18 g/cm3 |
| Melting point | 160 °C (320 °F; 433 K) |
| −9.06×10−6 (SI, 22°C) | |
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Refractive index (nD)
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1.4905 at 589.3 nm |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is ?) |
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| Infobox references | |
Poly(methyl methacrylate) (PMMA), also known as acrylic or acrylic glass as well as by the trade names Plexiglas, Acrylite, Lucite, and Perspex among several others (see below), is a transparent thermoplastic often used in sheet form as a lightweight or shatter-resistant alternative to glass. The same material can be utilised as a casting resin, in inks and coatings, and has many other uses.
Although not a type of familiar silica-based glass, the substance, like many thermoplastics, 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. Chemically, it is the synthetic polymer of methyl methacrylate. The material was developed in 1928 in several different laboratories by many chemists, such as William Chalmers, Otto Röhm and Walter Bauer, and was first brought to market in 1933 by the Rohm and Haas Company under the trademark Plexiglas.
PMMA is an economical alternative to polycarbonate (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. Non-modified PMMA behaves in a brittle manner when under load, especially under an impact force, and is more prone to scratching than conventional inorganic glass, but modified PMMA is sometimes able to achieve high scratch and impact resistance.
The first acrylic acid was created in 1843. Methacrylic acid, derived from acrylic acid, was formulated in 1865. The reaction between methacrylic acid and methanol results in the ester methyl methacrylate. In 1877 the German chemist Wilhelm Rudolph Fittig discovered the polymerization process that turns methyl methacrylate into polymethyl methacrylate. In 1933, the brand name "Plexiglas" was patented and registered by another German chemist, Otto Röhm. In 1936 Imperial Chemical Industries (now Lucite International) began the first commercially viable production of acrylic safety glass. During World War II both Allied and Axis forces used acrylic glass for submarine periscopes and aircraft windshields, canopies, and gun turrets. Airplane pilots whose eyes were damaged by flying shards of PMMA fared much better than those injured by standard glass, demonstrating the much-increased compatibility between human tissue and PMMA as compared to glass.
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Wikipedia