3F Condensation Polyimides-Review and Update
Abstract
The presence of the hexafluoroisopropylidene (6F) connecting group in aryl dianhydrides used to prepare aromatic polyimides provides high glass transition temperature (T sub g) polyimides that exhibit high thermo-oxidative stability (TOS) and good processability as matrix resins. The overall objective of this study was to determine if a phenyltrifluoroethylidene (1-phenyl-2,2,2- trifluoroethane, 3F) connecting group would have a similar effect as a 6F group on the processability, T sub g and TOS of aromatic polyimides. A new dianhydride containing the 3F connecting group was synthesized. This new 3F dianhydride (3FDA) and 3F diamine (3FDAM) were polymerized together and also with other diamines or dianhydrides to prepare new polyimides. The new 3F containing polyimides and analogous 6F polyimides were prepared by condensation polymerization via traditional amic-acid polymerizations in N,N- dimethylacetamide (DMAc). The amic-acid solutions, with two exceptions, had inherent viscosities greater than 0.45 dl/g, indicating that high molecular weight polymers had been formed. Structure-to-property relationships correlating inherent viscosity to the basicity of those diamine monomers which contained 3F and 6F connecting linkages were observed and explained in a prior report.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA217851
Entities
People
- Roy F. Gratz
- William B. Alston
Organizations
- National Aeronautics and Space Administration