Novel soluble ethynyl-terminated ester-imide prepolymers: their syntheses and characteristics

Novel soluble ester-imide prepolymers consisting of bisphenol-A bis(trimellitate) dianhydride (ESDA). aromatic diamine, and 3-ethynylaniline(3-EA) as the thermosetting groups were synthesized. The prepolymers were quite soluble in DMAc. DME m-cresol, NMP, CHCl3. and THF. The T-g's of the various prepolymers were from 200 to 250 degreesC. The properties of the cured resins of the prepolymers were evaluated, and showed a range of cured T-g's from 262 to 285 degreesC and flexural strengths of 112-138 MPa. A low moisture absorption of 0.45% and a low dielectric constant of 3.1 were also observed. Properties of glass-cloth-reinforced composites using the ester-imide prepolymers as the matrix resin were evaluated, and excellent mechanical and thermal properties were observed. An SEM photograph of a cross section of either the cured resin or the glass-cloth-reinforced composite showed good resin Row. Synthesis and some molecular orbital energies of ESDA were also studied.