Polymetylmetakrylat

Polymethyl methacrylate (PMMA), also known as acrylic glass, is a synthetic polymer derived from the methyl methacrylate monomer. It is a transparent, colorless thermoplastic with high optical clarity, good weather resistance, and a glass‑like feel. The repeating unit has the formula [-CH2-C(CH3)(COOCH3)-]n, and PMMA typically shows a glass transition temperature around 105 °C, a refractive index of about 1.49, and a density near 1.18 g/cm3.

PMMA is produced by addition polymerization of methyl methacrylate monomers using radical initiators. Polymerization can be carried out in bulk, solution, suspension, or emulsion processes, often with heat control due to the exothermic reaction. The material can be formulated with stabilizers and, in some cases, plasticizers to tailor properties for specific applications.

PMMA is noted for excellent optical properties, including high transmittance in the visible spectrum and low birefringence. It is relatively resistant to many chemicals and to weathering, though it can be attacked by certain solvents such as ketones and chlorinated hydrocarbons and may yellow under prolonged UV exposure unless stabilized. It tends to be more impact resistant than some glass types when modified with appropriate additives, though it can be brittle at low temperatures.

Common applications include glazing and architectural panels (skylights, display enclosures), automotive headlight lenses and instrument covers, signage, and lenses for optical devices. In dentistry, PMMA is used for denture bases and teeth; in medicine, for bone cements and intraocular lenses. It is also used in consumer electronics, display housings, and various engineering and hobbyist products.

PMMA is not biodegradable; recycling is possible by mechanical re-melting or chemical recycling. The polymer was developed in the early 20th century and became commercially important in the 1930s under brand names such as Plexiglas, Lucite, and Perspex.