Polymethyl methacrylate (PMMA) or poly(methyl 2-methylpropenoate) is the synthetic polymer of methyl methacrylate. This thermoplastic and transparent plastic is sold by the tradenames Plexiglas, Perspex, Acrylite, Acrylplast, and Lucite and is commonly called acrylic glass or simply acrylic. Properties The material is often used as an alternative to glass. Differences in the properties of the two materials include: PMMA is lighter: its density (1190 kg/m3) is about half that of glass. PMMA does not shatter. PMMA is softer and more easily scratched than glass. This can be overcome with scratch-resistant coatings. PMMA can be easily formed, by heating it to 100 degrees Celsius. PMMA transmits more light (92% of visible light) than glass. Unlike glass, PMMA does not filter UV (ultraviolet) light. PMMA transmits UV light, at best intensity, down to 300 nm. Some manufacturers coat their PMMA with UV films to add this property. PMMA allows infrared light of up to 2800 nm wavelength to pass. IR of longer wavelengths, up to 25,000 nm, are essentially blocked. Special formulations of colored PMMA exist to allow specific IR wavelengths to pass while blocking visible light (for remote control or heat sensor applications, for example). PMMA can be joined using cyanoacrylate cement (so-called \"Superglue\"), or by using liquid di- or trichloromethane to dissolve the plastic at the joint which then fuses and sets, forming an almost invisible weld. PMMA can also be easily polished to restore cut edges to full transparency. To produce 1 kg of PMMA, about 2 kg of petroleum is needed. In the presence of air, PMMA ignites at 460° C and burns completely to form only carbon dioxide and water. If hydrogen atoms are substituted for the methyl groups (CH3) attached to the C atoms, poly(methyl acrylate) is produced. This soft white rubbery material is softer than PMMA because its long polymer chains are thinner and smoother and can more easily slide past each other. Wiki:http://en.wikipedia.org/wiki/Plexiglass