Polyimides derived from nonaromatic monomers: synthesis, characterization and potential applications

• Published in: Reactive & functional polymers Vol. 30; no. 1; pp. 61 - 69
• Main Authors: Volksen, W., Cha, H.J., Sanchez, M.I., Yoon, D.Y.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.1996; Elsevier Science
• Subjects: Applied sciences; Cycloaliphatic; Dielectric constant; Exact sciences and technology; Mechanical properties; Organic polymers; Physicochemistry of polymers; Polycondensation; Polyimide; Preparation, kinetics, thermodynamics, mechanism and catalysts; Thermal stability; Mechanical properties; Polyimide; Cycloaliphatic; Dielectric constant; Thermal stability; Cyclobutane derivative polymer; Fluorine containing polymer; Dielectric properties; Optical properties; Preparation; Experimental study; Polyaddition
• ISSN: 1381-5148
• DOI: 10.1016/1381-5148(96)00024-7

A number of mixed aromatic/cycloaliphatic as well as fully nonaromatic polyimides have been prepared. Whereas all the poly(amic acids) derived from nonaromatic diamines involved salt-formation during the initial stages of the polymerization, the majority of these eventually formed homogeneous, highly viscous polymer solutions. Only in a few select cases involving all nonaromatic monomers traditional solution polymerization was unsuccessful. The polyimide derived from hexafluoroisopropylidene diphthalic anhydride (6FDA) and trans- 1,4-diaminocyclohexane (DACH) yielded films with tough mechanical properties, a glass transition temperature of ∼360°C, good solvent resistance, and a low dielectric constant of 2.6. Thermal stability of this polyimide as determined by thermal gravimetric analysis in both air and nitrogen was quite good, exhibiting a weight loss of only 0.07 wt%/h at 350°C under isothermal conditions in nitrogen. However, mechanical properties as a function of thermal aging in both air and nitrogen indicated a maximum use temperature of only 350°C under inert conditions and less than 300°C in the presence of oxygen.