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A series of new oligoimides based on 4,4- and 3,4-oxydianiline and 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, possessing different average chain lengths, and containing terminal propargyl groups were synthesized according to an efficient single-step high-temperature polycyclocondensation method. Their molecular weight characteristics, solubility in organic solvents, thermal (DSC, TMA, and TGA), and rheological properties were studied. The synthesized oligoimides exhibited a significantly lower exothermic effect upon curing due to their elongated chain as compared to diimides. The oligoimides upon increasing the temperature enter into a viscous fluid state, in which they remain up to the curing onset temperature of 270–320 °C. The symmetry of structure of the diamine moiety (4,4-ODA or 3,4-ODA) and the molecular weight of oligoimides affect the temperature of transition to the viscous fluid state. [ABSTRACT FROM AUTHOR]

A series of new thermosetting diimides containing terminal propargyl groups was synthesized via one-step high-temperature catalytic condensation of dianhydrides of a tetracarboxylic acid with N-Boc-(4-propargyloxy)aniline (APR) in the so-called "active medium", viz. molten benzoic acid. Structures of the obtained compounds were confirmed by 1H NMR and IR spectroscopy. The effect of symmetrical and unsymmetrical structures of the middle bis-imide moiety obtained from dianhydrides of isomeric diphenyltetracarboxylic acid on physicochemical characteristics of the diimides was evaluated. A similar comparison of properties was also carried out for a pair of new propargyl-containing diimides synthesized from dianhydrides of symmetric and asymmetric structure: 4,4-biphenylenedioxydiphthalic and 3,4-biphenylenedioxydiphthalic dianhydrides, respectively. Thermal properties of thermosetting oligoimides were estimated using DSC and TMA methods. It was found that their thermal properties and solubility in organic solvents depend significantly on the structure of central bis-imide moiety. [ABSTRACT FROM AUTHOR]