AbstractThe structure and properties of an unusual new polyamide copolymer derived from 2,2‐bis‐(4‐aminoeyclohexyl)propane and a 60/40 molar mixture of azelaic and adipic acids are described. The alicyclic diamine structure, with its cyclohexyl rings and central gem‐dimethyl group, contribute to chain stiffness and amorphous character in the polyamide, and sets it apart from more common polyamides (e.g., nylon 6–6) with their relatively flexible polymer chains, low glass transition temperatures and high levels of crystallinity. The particular combination of dicarboxylic acids employed yields a resin with a high glass transition temperature (185°C). This amorphous, colorless material is exceptionally transparent, with a high luminous transmission (92 percent) and low haze (0.5 percent). The polymer is tough and resistant to scratching and abrasion and to attack by chemicals and solvents. Its high glass transition temperature leads to a high heat deflection temperature (160°C) and excellent retention of its mechanical properties at elevated temperatures. It is an atypical nylon in that its dimensions, mechanical properties and electrical properties are relatively unaffected by changing moist