Colourless, thermoplastic polymer or copolymer of acrylic acid, methacrylic acid or acrylonitrile. Acrylic resins are a commercially important family of polymers that were first discovered in 1880 by the Swiss chemist Georg W.A. Kahlbaum. Otto Röhm of Germany thoroughly described their production in his doctoral thesis (1901) then later patented the process in 1915. Polymethyl methacrylate was first marketed by Rohm and Haas in Germany in 1927. Acrylics have been sold as glass substitutes and as adhesives, varnishes and paint media. Acrylic resins range from soft, tacky materials to hard solids. They are glossy, crystal clear with good shock and water resistance. They are stable to outdoor weathering and resistant to chemicals including by mild acids and bases. Acrylics are used as paints, coatings and adhesives. Synonyms : acrylics; acrylate; methacrylate; Plexigum® [Rohm & Haas]; Lucite® [DuPont]; Paraloid® [Rohm & Haas]; Elvacite® [DuPont]; Plexiglas® [Rohm & Haas]; Perspex®; Magna [Bocour]; Liquitex [Permanent Pigments]; Shiva [Shiva]; Hyplar [Grumbacher]; Aqua-tec [Bocour]. Museum of Fine Arts, Boston (2000). [J. Cassar, R. de Angelis]