Polypyromellitimide, aliphatic

Example 2.3 Polyimides have been prepared from aromatic anhydrides and aliphatic diamines by melt fusion of salt from the diamine and tetracid (dianhydride). Ahphatic polypyromellitimide derived from straight-chain aliphatic diamines containing more than nine carbon atoms gave thin, flexible films, whereas those from shorter chain aliphatic diamines allowed the preparation of only thick, brittle moldings. Explain this observation. 

Polypyromellitimides have been prepared by condensation in solution of NMP from aliphatic diamines and A, A -dialkyloxycarbonyl pyromellitimides. The reaction can be carried out by interfacial polycondensation, as illustrated in Scheme (19) [123,124]. 

Polyimide Synthesis from Nylon-Salt-Type Monomers. The microwave-assisted polycondensation was further applicable to the effective, rapid synthesis of aliphatic polypyromellitimides from the salt monomers XPMA and XPME composed of aliphatic diamines and both pyromellitic acid PMA and its diethyl ester PME (Eqs 3 and 4). 

Aliphatic polypyromellitimides were synthesized from the reaction of the salt monomers composed of ahphatic diamines (the length of the diamines chain was 6-12-CH2-moieties) and pyromelhtic acid or its diethyl ester in domestic micro-wave oven (Imai et al., 1996b). Polar oiganic media such as NMP, CHP, DMI and TMS were used. l,3-Dimethyl-2-imidazohdone was the best polymerization medium for this polycondensation. Polymers were obtained with inherent viscosities of about 0.70 dL/g or above only in 2 min. 

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