Computer graphics representation of the chemical structure of the bakelite monomer, the structural unit of a thermosetting plastic polymer. Thermosetting plastics or resins are condensation polymers composed of complex three-dimensional, cross-linked networks. Once polymerized, thermosetting plastics cannot be remoulded by heating - articles made in bakelite are hard and permanent. Bakelite, the first commercially- successful plastic, was discovered in the 1920's by the Belgian-born chemist Leo Baekeland whilst he was doing research on synthetic varnishes in the U.S. Image modelled using Chemical Design's Chem-X software.