A facile solid-state synthesis of crystalline oxydianiline-based polypyromellitimides via salt monomers

A new direct preparation of electroconductive polyimide/carbon black composite via polycondensation of nylon-salt-type monomer/carbon black mixture

“…The carbon black composed of both aliphatic and aromatic diamines, and had a specific surface area of about 800 m 2 /g, primary aromatic tetracarboxylic acids or the corresponding diparticle diameter of about 30 nm, density of 1.8 g/cm 3 , acid diesters. [5][6][7][8][9][10] and electrical conductivity of around 10 2 S/cm. By the extension of this finding, we have developed a simple method for the preparation of an electroconductive polyimide/carbon black composite directly from Preparation of Composite the monomer.…”

High-pressure synthesis of aliphatic polypyromellitimides via nylon-salt-type monomers composed of aliphatic diamines and pyromellitic acid diesters

“…Although the endothermic peak temperatures of the salt monomers XPME, which correspond to the imideforming reaction temperatures as reported previously, [7][8][9][10][11][12] were some 50 -90°C lower than those of the parent salt monomers XPMA, the melting temperatures (T m ) of polyimides P-XPM from the salt monomers XPME agreed very closely with those of the polymers from the parent salts XPMA, as summarized in Table I. 11 Since both of the aliphatic polypyromellitimides prepared by the high-pressure polycondensation were inherently high crystalline nature, no glass transition temperatures were detected on the DSC traces.…”

“…The separation of the two isomers was achieved by fractional recrystallization from chlorobenzene. Melting points of mPME and PME were 178°C and 216 -218°C, 8 respectively.…”

“…Pyromellitic acid (PMA) was prepared by a usual hydrolysis of PMDA with water. 11,15 Pyromellitic acid m-and p-diethyl esters (mPME and PME, respectively) were synthesized according to the reported procedure 8,15 by the reaction of PMDA with absolute ethanol. The separation of the two isomers was achieved by fractional recrystallization from chlorobenzene.…”

“…1,5,6 Recently we reinvestigated this kind of salt monomer method and found that the nylon-salt-type monomers were extremely reactive, producing directly polyimides by the polycondensation even under high pressure in a very short reaction time at a temperature around 250°C . [7][8][9][10][11][12][13] The present study has two objectives. The one is to compare the polymer-forming reactivity of the two isomeric nylon-salt-type monomers derived from both pyromellitic acid m-and p-substituted diethyl esters with dodecamethylenediamine, and the properties of the two resultant polyimides with each other (Scheme 1).…”