Synthesis and Characterization of Amorphous Partially Aliphatic Polyimide Copolymers Based on Bisphenol-A Dianhydride

• Published in: Macromolecules Vol. 35; no. 20; pp. 7561 - 7568
• Main Authors: Eichstadt, Amy E, Ward, Thomas C, Bagwell, Melanie D, Farr, Isaac V, Dunson, Debra L, McGrath, James E
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 24.09.2002
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polycondensation; Preparation, kinetics, thermodynamics, mechanism and catalysts; Refraction index; Head to head polymer; Experimental study; Polyaddition; Amorphous copolymer; Dielectric relaxation; Thermal properties; Etherimide copolymer; Optical properties; Preparation; Thermal expansion coefficient; Soluble compound; Activation energy
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma020835p

Partially aliphatic, high molecular weight polyimide copolymers were successfully synthesized using an ester−acid high-temperature solution imidization route by which noncrystalline, soluble materials were obtained. Variations in the aliphatic content produced a series of polyimides having different glass transition temperatures and processing characteristics. The ester−acid reaction pathway eliminated the need for anhydrous solvents and overcame the problem of salt formation commonly observed for nucleophilic, more basic, aliphatic amines prepared by the traditional poly(amic acid) synthesis route. Partially aliphatic polyimides containing either a cycloaliphatic diamine or aliphatic diamines with 6 or 12 methylene units were synthesized. Each copolymer was characterized by its molecular weight, glass transition temperature, thermal stability, coefficient of thermal expansion, refractive index, and dielectric constant. Structure−property relationships were established. The γ and β sub-T g viscoelastic relaxations were explored in order to understand their molecular origins.